Genetics, breeding and selection - Cattle

 

Inaba, Y.; Tsurifune, K.; Sasazaki, S.; Mannen, H. (2008) A New Tandem Repeat in Bovine Fibrinogen Aalfa Gene Animal Biotechnology, 19 (2):  122 - 126

 

KEYWORDS: Cattle; Connector; Fibrinogen Aalfa; Polymorphism; Tandem repeat

 

SUMMARY: In this study, intraspecies variation in the alfaC connector region of the bovine fibrinogen Aalfa gene was described. Sequencing and genotyping of six bovine breeds revealed 7 to 10 tandem repeats in the alfaC connector region. In addition, we observed length differences between B. indicus and B. taurus, with the B. indicus having longer fibrinogen alfaC connectors (10-repeat alleles) than B. taurus (7- and 9-repeats).

 

Buch, L. H.; Norberg, A. (2008) Genetic analysis of protein yield, udder health, and female fertility in first-parity Danish Holstein cows Acta Agriculturae Scandinavica, Section A - Animal Sciences, 58 (1): 5 - 9

 

KEYWORDS: Dairy cow; fertility; genetic correlation; udder health

 

SUMMARY: Genetic parameters for protein yield, clinical mastitis, SCS, number of inseminations (NI), and days from first to last insemination (FLI) were estimated for first-parity Danish Holstein cows. The objective was to estimate genetic correlations between the five traits mentioned above and to study whether NI and FLI are measures of the same trait. Records containing information on approximately 200 000 cows were analysed using tri-variate animal models. The genetic correlations between the udder health traits and the fertility traits were favourable and in the range from 0.17 to 0.42, whereas the genetic correlations between protein yield and the fertility traits were unfavourable and ranged from 0.43 to 0.52. These results highlight the importance of continuing to emphasize functional traits in future breeding programmes. The genetic correlation between the fertility traits was 0.82.

 

Sørensen, L. P.; Guldbrandtsen, B.; Thomasen, J. R.; Lund, M. S. (2008) Pathogen-Specific Effects of Quantitative Trait Loci Affecting Clinical Mastitis and Somatic Cell Count in Danish Holstein Cattle Journal of Dairy Science, 91:2493-2500

 

KEYWORDS: quantitative trait loci; mastitis; somatic cell score; pathogen specificity

 

SUMMARY: The aim of this study was to investigate whether quantitative trait loci (QTL) affecting the risk of clinical mastitis (CM) and QTL affecting somatic cell score (SCS) exhibit pathogen-specific effects on the incidence of mastitis. Bacteriological data on mastitis pathogens were used to investigate pathogen specificity of QTL affecting treatments of mastitis in first parity (CM1), second parity (CM2), and third parity (CM3), and QTL affecting SCS. The 5 most common mastitis pathogens in the Danish dairy population were analyzed: Streptococcus dysgalactiae, Escherichia coli, coagulase-negative staphylococci, Staphylococcus aureus, and Streptococcus uberis. Data were analyzed using 2 approaches: an independence test and a generalized linear mixed model. Three different data sets were used to investigate the effect of data sampling: all samples, only samples that were followed by antibiotic treatment, and samples from first-crop daughters only. The results showed with high certainty that 2 QTL affecting SCS exhibited pathogen specificity against Staph. aureus and E. coli, respectively. The latter result might be explained by a pleiotropic QTL that also affects CM2 and CM3. Less certain results were found for QTL affecting CM. A QTL affecting CM1 was found to be specific against Strep. dysgalactiae and Staph. aureus, a QTL affecting CM2 was found to be specific against E. coli, and finally a QTL affecting CM3 was found to be specific against Staph. aureus. None of the QTL analyzed was found to be specific against coagulase-negative staphylococci and Strep. uberis.

 

Lidauer, M.H.; Emmerling, R.; Mäntysaari, E.A. (2008) Multiplicative random regression model for heterogeneous variance adjustment in genetic evaluation for milk yield in Simmental Journal of Animal Breeding and Genetics, 125 (3): 147–159

 

KEYWORDS: across-country evaluation; dairy cattle; heterogeneous variance; test-day model

 

SUMMARY: A multiplicative random regression (M-RRM) test-day (TD) model was used to analyse daily milk yields from all available parities of German and Austrian Simmental dairy cattle. The method to account for heterogeneous variance (HV) was based on the multiplicative mixed model approach of Meuwissen. The variance model for the heterogeneity parameters included a fixed region × year × month × parity effect and a random herd × test-month effect with a within-herd first-order autocorrelation between test-months. Acceleration of variance model solutions after each multiplicative model cycle enabled fast convergence of adjustment factors and reduced total computing time significantly. Maximum Likelihood estimation of within-strata residual variances was enhanced by inclusion of approximated information on loss in degrees of freedom due to estimation of location parameters. This improved heterogeneity estimates for very small herds. The multiplicative model was compared with a model that assumed homogeneous variance. Re-estimated genetic variances, based on Mendelian sampling deviations, were homogeneous for the M-RRM TD model but heterogeneous for the homogeneous random regression TD model.

 

Ibi, T.; Kahi, A.K.; Hirooka, H. (2008) Genetic parameters for gestation length and the relationship with birth weight and carcass traits in Japanese Black cattle Animal Science Journal, 79 (3): 297–302

 

KEYWORDS: carcass trait; genetic parameter; gestation length; Japanese Black cattle

 

SUMMARY: The objectives of this study were to estimate genetic parameters for gestation length (GL), including estimation of maternal effects, and to investigate the genetic relationships of GL with birth weight and carcass traits in a Japanese Black cattle population. The original data comprised 34 775 records of animals born from October 1999 to August 2003. Two different models were used to analyze the data for GL. The first model (M1) included direct genetic effect of the calf and maternal genetic effect as random effects. The second model (M2) treated GL as a trait of the dam and included direct genetic effects only. M1 was used in bi-variate analysis. The direct and maternal heritabilities for GL estimated from M1 were 0.53 and 0.14, respectively. This result shows that GL is moderately inherited and can be controlled genetically. The direct × maternal genetic correlation for GL was −0.73. Direct genetic correlations of GL with carcass traits were close to zero. However, genetic correlation of maternal GL with carcass weight was moderate (0.25).

 

Okanishi, T.; Shojo, M.; Katsuta, T.; Oyama, K.; Mukai, F. (2008) Genetic analysis of residual feed intakes and other performance test traits of Japanese Black cattle from revised protocol Animal Science Journal, 79 (3): 291–296

 

KEYWORDS: genetic parameter; growth trait; Japanese Black cattle; performance test; residual feed intake

 

SUMMARY: The performance test protocol for Japanese Black cattle was revised in April 2002. This resulted in restriction of access to concentrate (based on body weight) and modification of the concentrate's ingredients. Genetic parameters of growth and feed utilization traits of the performance test were estimated using 1304 records using the revised protocol. Residual feed intakes (RFIs) as alternative indicators for feed utilization efficiency were included. (Co)variance components were estimated by EM-REML. Heritabilities for growth traits were between 0.26 and 0.47. Heritabilities for feed intakes and conversions ranged from 0.25 to 0.37 and from 0.03 to 0.29, respectively. Genetic variances and heritabilities were lower for the revised protocol. Highly positive genetic correlations of daily gain (DG) with feed intakes indicated selection on DG is expected to increase feed intake. Selection on feed conversion may lead to higher DG. The heritability estimates for RFIs ranged from 0.10 to 0.33 and were generally higher than corresponding estimates for feed conversion ratios. RFI of TDN showed positive genetic correlations with all feed intakes. The reduction of feed intakes could be expected through selection on the RFI without changing body size.

 

Helgeson, S. C.; Schmutz, S. M. (2008) Genetic variation in the pro-melanin-concentrating hormone gene affects carcass traits in Bos taurus cattle Animal Genetics, 39 (3): 310–315

 

KEYWORDS: average fat; BTA5; E4BP4; grade fat; MCH; NEI; NGE

 

SUMMARY: Mammalian pro-melanin-concentrating hormone (PMCH) has previously been shown to affect feed intake in rodent species. The objectives of this study were to sequence the Bos taurus PMCH gene in order to identify any existing genetic variants and to evaluate whether these affected carcass traits. An A-to-T SNP was identified at position −134 relative to the ATG start codon (g.-134A>T). The alleles at this SNP were significantly associated with average fat and grade fat in two crossbred populations of Bos taurus cattle. The g.-134T allele may introduce a binding site for the transcriptional repressor, adenovirus E4 promoter binding protein, which may contribute to this effect. The g.-134A allele occurred in 67% of cattle examined and was associated with higher fat levels.

 

DeVuyst, E. A.; Bauer, M. L.; Cheng, F.-C.; Mitchell, J.; Larson, D. (2008) The impact of a leptin gene SNP on beef calf weaning weights Animal Genetics, 39 (3): 284–286

 

KEYWORDS: calf weaning weight; leptin; single nucleotide polymorphism

 

SUMMARY: Prior research indicates that a SNP at position 305 of exon 2 in the leptin gene affects milk production in dairy cows. Dairy cows with at least one copy of the T allele have been shown to have higher milk production than CC cows. If that effect carries over to beef breeds, it is reasonable to expect that CT and TT beef cows will wean heavier calves than CC beef cows. This hypothesis was tested on a herd of mixed breed cows using anova. Results indicated that both crossbred CT and TT beef cows wean significantly heavier beef calves than CC crossbred beef cows. A lack of observations generally hinders detection of significance in other breeds. However, two other comparisons were found to be significant. The results suggest further investigation into the link between leptin genotype and calf weaning weights.

 

Sherman, E. L.; Nkrumah, J. D.; Murdoch, B. M.; Moore, S. S. (2008) Identification of polymorphisms influencing feed intake and efficiency in beef cattle Animal Genetics, 39 (3): 225–231

 

KEYWORDS: beef cattle; feed efficiency; feed intake; polymorphisms; residual feed intake

 

SUMMARY: SNPs that show associations with residual feed intake (RFI) may be useful quantitative trait nucleotides for marker-assisted selection. This study identified associations between SNPs underlying five RFI QTL on five bovine chromosomes (BTA2, 5, 10, 20 and 29) with measures of dry matter intake (DMI), RFI and feed conversion ratio (FCR) in beef cattle. Six SNPs were found to have effects on RFI (P < 0.05). The largest single SNP allele substitution effect for RFI was −0.25 kg/day located on BTA2. The combined effects of the SNPs found significant in this experiment explained 6.9% of the phenotypic variation of RFI. Not all the RFI SNPs showed associations with DMI and FCR even though these traits are highly correlated with RFI (r = 0.77 and r = 0.62 respectively). This shows that these SNPs may be affecting the underlying biological mechanisms of feed efficiency beyond feed intake control and weight gain efficiency.

 

Anton, I.; Kovács, K.; Fésüs, L.; Várhegyi, J.; Lehel, L.; Hajda, Z.; Polgár, J.P.; Szabó, F.; Zsolnai, A. (2008) Effect of DGAT1 AND TG gene polymorphisms on intramuscular fat and on milk production traits in different cattle breeds in Hungary Acta Veterinaria Hungarica, 56 (2): 181–186

 

KEYWORDS: Cattle, TG, DGAT1, PCR-RFLP, intramuscular fat, dairy traits

 

SUMMARY: The objective of this study was to estimate the effect of the thyroglobulin (TG) locus on beef quality traits in some beef cattle breeds and to investigate the effect of the DGAT1 locus on milk production traits in the Hungarian Holstein Friesian population. TG and DGAT1 genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. At the TG locus TT bulls showed the highest fat percentage values in the longissimus dorsi muscle (m. longissimus dorsi); the difference between CC and TT genotypes was significant. DGAT1 GC/GC cows had the highest milk, fat and protein yield values. Due to the relatively small number of GC/GC cows the difference proved to be significant only between AA/AA and AA/GC genotypes

 

Gutiérrez-Gil, B., Wiener, P., Nute, G.R., Burton, D., Gill, J.L., Wood, J.D. and Williams, J.L. (2008) Detection of quantitative trait loci for meat quality traits in cattle Animal Genetics, 39, 51–61

 

KEYWORDS: Beef, meat quality, quantitative trait loci, sensory panel

 

SUMMARY: The next challenge for the beef industry is to improve carcass consistency and eating quality of meat. Eating quality includes various taste-related traits such as tenderness, flavour and juiciness, appearance, nutrient content and safety. In order to detect quantitative trait loci (QTL) affecting sensory, organoleptic, physical and chemical properties of meat, a whole-genome scan was carried out. The study used phenotypic data from 235 second-generation cross-bred bull calves of a Charolais × Holstein experimental population. A linear regression analysis based on 165 markers revealed 35 QTL at the 5% chromosome-wide significance level (20 for sensory traits and 15 for physical and chemical traits), five of which were highly significant. At this level of significance and considering the level of multiple testing (29 chromosomes × 19 traits), one might expect 28 associations to be identified by chance alone. The most significant QTL was located on chromosome 6 and affected haem pigment concentration. However, five other new significant QTL were detected, on chromosomes 6, 22 and 29 when marker density was increased. These were moisture on chromosome 6, G-b-flavour on chromosome 12, R-b-flavour and R-ab-odour on chromosome 22 and R-ab-flavour on chromosome 29.

 

Dalvit, C., De Marchi, M., Dal Zotto, R., Zanetti, E., Meuwissen, T., Cassandro, M. (2008) Genetic characterization of the Burlina cattle breed using microsatellites markers Journal of Animal Breeding and Genetics, 125 (2): 137–144

 

KEYWORDS: Burlina, dairy cattle, genetic characterization, genetic diversity, microsatellite

 

SUMMARY: The present study was a contribution on the genetic characterization of the Burlina local cattle breed, and an approach to understanding the relationships between Burlina, Holstein Friesian and Brown Swiss which represent the majority of the dairy cattle reared nowadays in North-East Italy. The obtained results helped to clarify the genetic diversity and distinctiveness of Burlina population. In particular, the low genetic distance between Burlina and Holstein Friesian and the assignment of a moderate percentage of Burlina animals to Holstein Friesian suggested that crosses between them took place in the past, while crosses with Brown Swiss seemed to be less frequent. However, analyses of marker genotypes, showed a cluster with only Burlina individuals, which demonstrates the genetic distinctness of this breed. The Burlina breed showed the highest variability among the analysed breeds and its inbreeding coefficient was low.

 

Kűhn, C., Reinhardt, F., Schwerin, M. (2008) Marker assisted selection of heifers improved milk somatic cell count compared to selection on conventional pedigree breeding values Archives of Animal Breeding, 51: 23-32

 

KEYWORDS: Marker assisted selection, heifers, somatic cell count, conventional pedigree, breeding values

 

SUMMARY: Although mastitis in cattle is an important factor for dairy economy and animal welfare and although udder health parameters have a substantial genetic variability, in many countries there is little or no improvement of udder health in the conventional commercial breeding programs. Strategies implementing information about Quantitative trait loci (QTL) via genetic marker information seem to offer new prospects to improve this situation. In a proof-of-principle approach, it was shown that selection of German Holstein heifers prior to first calving based on marker information regarding a confirmed QTL affecting somatic cell score (SCS) on bovine chromosome 18 (BTA18) (MAS strategy) enabled prediction of halfsibs with a high (q) or a low (Q) number of somatic cells in milk early in the first lactation. Compared to a strategy relying on conventional breeding values only (CON strategy), selection including marker information resulted in a stronger discrimination between and a higher uniformity within the MAS-Q and -q groups compared to the CON-Q and -q groups selected by conventional selection strategies.

Guo, H., Liu, W-S., Takasuga, A., Eyer, K., Landrito, E., Xu, S-Z., Gao, X., Ren, H-Y. (2008) Mapping and association of GAD2 and GIP gene variants with feed intake and carcass traits in beef cattle (short communication) Archives of Animal Breeding, 51:33-41

 

KEYWORDS: Mapping, GAD2, GIP, feed intake, carcass traits, beef cattle

 

SUMMARY: Glutamate decarboxylase 2 (GAD2) is a major autoantigen in insulin-dependent diabetes, while glucose-dependent insulinotropic polypeptide (GIP) is a gastrointestinal hormone. Both genes are involved in insulin secretion and play a role in the regulation of feed intake and metabolic rate in animals. In the present study, the bovine GAD2 and GIP were assigned by RH mapping to BTA 13 and BTA 19, respectively. SNPs were discovered from these genes by a PCR-sequencing approach. One SNP (T/C transition) was identified from the 14 intron of the bovine GAD2 gene and another SNP (A/C transversion) from the 4 intron of the bovine GIP gene. Genotyping over 300 animals from five different beef populations revealed that the average allelic frequency for the GAD2 allele A was 0.48 and allele B 0.52, while for the GIP allele A 0.80 and allele B 0.20, respectively. There were significant associations observed between the GAD2 and GIP gene variants and Average Daily Feed Intake (ADFI) (p<0.05) in beef cattle. In addition, the GAD2 SNP was also associated with Meat Percent (MP) (p<0.05), whereas the GIP SNP was also significantly associated with Backfat Thickness (BF) (p<0.05) and Ratio of Feed-to-Meat (RFM) (p<0.05). There were no significant effects found for other traits.

 

Shirley, K. L., Beckman D. W., Garrick, D. J. (2008) Inheritance of pulmonary arterial pressure in Angus cattle and its correlation with growth Journal of Animal Science, 86: 815-819

 

KEYWORDS: Cattle, growth, heritability, maternal effect, pulmonary arterial pressure

 

SUMMARY: (Co)-variancecomponents for PAP, birth weight, and adjusted 205-d weaningweight were estimated from 2,305 spring-born, registered Anguscattle A singlemeasure of PAP was collected after weaning on animals born from1984 to 2003. Multitrait animal models with and without PAP maternaleffects were fitted. The interaction of year x sex was a significant fixed effectfor PAP, but age of dam was not. Age at PAP testingwas a significant linear covariate for PAP, andscores increased 0.012 ± 0.007 mmHg·dof age. Heritability of PAP direct was 0.34 ± 0.05. Maternalheritability converged to a boundary at 0.0, and the model withmaternal genetic effects for PAP was not significantly betterthan a model with only direct effects. Phenotypically, PAP wasuncorrelated with birth or weaning weights. Genetically, PAPappeared to have positive, unfavorable relationships with directeffects for birth (0.49 ± 0.12) and weaning weight (0.50± 0.18). Positive correlations imply sires whose offspringexhibited resistance to brisket disease had lower weights andgains. A model that evaluated PAP in females and males as differenttraits had heritability estimates for each sex of 0.38 ±0.07 and 0.46 ± 0.09, respectively, with a genetic correlationof 0.64 ± 0.12 between the sexes and was not significantlybetter than the model assuming homogeneity by sex and a unitgenetic correlation between sexes.

 

Bryant, Jeremy; Lopez-Villalobos, Nicolas; Holmes, Colin; Pryce, Jennie; Rossi, Jose; Macdonald, Kevin (2008)  Development and evaluation of a pastoral simulation model that predicts dairy cattle performance based on animal genotype and environmental sensitivity information Agricultural Systems, 97 (1-2), 13-25

 

KEYWORDS: Genotype; environment; dairy cattle; simulation; evaluation

 

SUMMARY: Most simulation models that are currently available for dairy production do not fully succeed in including genetic information, or in integrating the effect of G×E interactions in dairy cattle systems. Moreover, feed intake or potential milk yield needs to be specified for use in simulation models, which requires prior feed intake measurements or detailed knowledge of the animal genotype and how it responds to an environment. In this study, Bryant et al. describe a dairy cattle simulation model for pastoral systems that applies a modular approach to predict milk yields and live weight change in dairy cattle, with feed intake being an output determined by the cumulative effect of each animal module. According to the results from the study, the model simulated, to a high degree of accuracy, mean values for daily yields of milk, fat and protein, and concentrations of fat and protein of two modern Holstein-Friesian genotypes based on genetic and environmental information. On the other hand, feed intake and live weight change were simulated less reliably. Despite that model has been developed for New Zealand production systems, the aim is for the concepts and functions to be applied and transferred to all production systems and cows.

 

Kasai Kouji, Sano Fumihiko, Miyashita Norikazu, Watanabe Shinya, Nagai Takashi (2007) Comparison of the Growth Performances of Offspring Produced by a Pair of Cloned Cattle and Their Nuclear Donor Animals Journal of Reproduction and Development, Vol. 53, No. 1, 2007

 

KEYWORDS: Cattle, Calf of clones, Full siblings, Growth performance, Somatic cell cloning

 

SUMMARY: According to authors, there are a number of potential advantages that come from the use of cloned livestock such as making genetic copies of elite seed stock and preservation of endangered breeds. However, many studies that have investigated the link between errors in epigenetic modification shown that cloned embryos have epigenetic errors that cause loss of embryos and fetuses during differentiation and development in the uterus. Kasai et al. carried out this study in order to compare the growth performance of offspring obtained by mating a pair of cloned cattle with that of full siblings produced by mating the nuclear donors of the cloned animals. Results from this research show that the mating of a cloned dam and sire of the Japanese Black breed produced a calf whose birth weight was within the normal rage for Japanese Black breed cows. These observations would suggest that large offspring syndrome was not a problem among the progeny of pairs of clones in these studies. Also, the present study shows that the growth curves for body weight and shoulder height of the calf of clones were within the range of its full siblings produced by crossing the animals used as nuclear donors.

 

Crews D.H., Enns R.M., Rumph J.M., Pollak E.J. (2008) Genetic evaluation of retail product percentage in Simmental cattle Journal of Animal Breeding and Genetics, 125 (2008) 13–19

 

KEYWORDS: Beef cattle; carcass; genetic regression; retail product; Simmental

 

SUMMARY: Since that the many beef breed associations maintain carcass databases which are used in their cattle evaluation systems, it is necessary to estimate genetic parameters required for genetic evaluation. The objectives of this research were to develop an appropriate model and to estimate genetic parameters for component carcass traits and to derive parameters for retail product percentage in North American Simmental cattle. Obtained results suggest that for Simmental-sired beef calves increases in carcass weight were more closely related to increases in muscle size than with deposition of subcutaneous and (or) body cavity fat. Further, increased muscle size and fat deposition were either negatively correlated or not correlated, suggesting that when compared at age constant end points these cattle were partitioning more weight gain into muscle rather than fat. A heritability estimate was obtained for retail product percentage based on the fact that it is simply a linear combination of the component carcass traits suggesting that predicted retail product percentage has a moderate heritability, and therefore expected to respond to selection. However, the genetic parameter estimates obtained suggest that inclusion of kidney, pelvic and heart fat in prediction of retail product percentage is of marginal value.

 

Ndumu, D.B.; Baumung, R.; Wurzinger, M.; Drucker, A.G.; Okeyo, A.M.; Semambo, D.; Sölkner, J. (2008) Performance and fitness traits versus phenotypic appearance in the African Ankole Longhorn cattle: A novel approach to identify selection criteria for indigenous breeds Livestock Science, 113 (2-3): 234-242

 

KEYWORDS: Indigenous selection criteria; Phenotypic ranking; Ankole cattle; Multinomial logistic regression

 

SUMMARY: Two experiments with traditional cattle keepers were carried out at a governmental Ankole nucleus farm in south-western Uganda to identify phenotypic characteristics as well as production and fitness traits which are important indigenous selection criteria. Forty one body measurements each were taken from 15 bulls and 35 cows and phenotypic characteristics were described in detail. In the first experiment 12 groups of 6 to 8 cattle keepers were invited to rank several groups of 4–5 animals according to their preference for a breeding bull or cow based on phenotype alone. In the second experiment the ranking was based on phenotype and a hypothetical life history that was randomly assigned to each animal on each day of experiment. The history included milk yield, fertility of the animal and its sire and events of East Coast Fever. Generalized Multinomial Logit Models were fitted. To compare different models, the likelihood-based pseudo R square measure was used. The results indicate that, in the selection of cows, performance and fitness traits are emphasized by the cattle keepers while in the selection of bulls, the phenotypic appearance of the animal plays an important role. Individual fertility followed by milk performance are the main criteria for selecting cows, resistance to East Coast Fever was of highest importance in bulls.

 

Davis, G. P.; Moore, S. S.; Drinkwater, R. D.; Shorthose, W. R.; Loxton, I. D.; Barendse, W.; Hetzel, D. J. S. (2008) QTL for meat tenderness in the M. longissimus lumborum of cattle Animal Genetics, 39 (1): 40–45

 

KEYWORDS:  QTL, meat tenderness, M. longissimus lumborum, cattle

 

SUMMARY: Meat tenderness has been difficult to improve using standard genetic selection. Marker assisted selection holds great promise if markers for meat tenderness can be identified. Here, we report quantitative trait loci (QTL) for beef tenderness identified in 598 animals of three Charolais–Brahman × Belmont Red pedigrees after screening the whole genome using 183 DNA markers. In addition to the usual Warner–Bratzler peak force measurements, tenderness was also measured using compression, adhesion and pressure-heat-treated peak force. Three QTL for meat tenderness in the M. longissimus lumborum muscle were found, two of which have not been reported before. One is located in the HEL9-CSSM47 interval on bovine chromosome 8 with a LOD of 3.1 and an effect of 1.02 phenotypic standard deviations for tensile strength of cooked muscle as measured by adhesion. A second QTL is located near CSRM60 on bovine chromosome 10 with a LOD of 2.4 and an effect of 0.48 phenotypic standard deviations for compression. The third QTL is in a region of bovine chromosome 7 that has previously been reported to have a QTL affecting peak force. This region also shows effects on compression and a combined tenderness index. These QTL are all for the myofibrillar component of meat tenderness. No QTL were found for pressure-treated peak force, which is an estimate of the connective tissue component muscle of meat tenderness

 

Masoudi, A. A.; Uchida, K.; Yokouchi, K.; Ohwada, K.; Abbasi, A. R.; Tsuji, T.; Watanabe, T.; Hirano, T.; Sugimoto, Y.; Kunieda, T. (2008) Linkage mapping of the locus responsible for forelimb-girdle muscular anomaly of Japanese black cattle on bovine chromosome 26 Animal Genetics, 39 (1): 46–50

 

KEYWORDS: Linkage mapping, forelimb-girdle muscular anomaly, Japanese black cattle. bovine chromosome 26

 

SUMMARY: Forelimb-girdle muscular anomaly is an autosomal recessive disorder of Japanese black cattle characterized by tremor, astasia and abnormal shape of the shoulders. Pathological examination of affected animals reveals hypoplasia of forelimb-girdle muscles with reduced diameter of muscle fibres. To identify the gene responsible for this disorder, a linkage mapping of the disorder locus was performed using an inbred pedigree including a great-grand sire, a grand sire, a sire and 26 affected calves obtained from a herd of Japanese black cattle. Two hundred and fifty-eight microsatellite markers distributed across the genome were genotyped across the pedigree. Four markers on the middle region of bovine chromosome 26 showed significant linkage with the disorder locus. Haplotype analysis using additional markers in this region refined the critical region of the disorder locus to a 3.5-Mb interval on BTA26 between BM4505 and MOK2602.

 

Gutiérrez-Gil, B.; Wiener, P.; Nute, G. R.; Burton, D.; Gill, J. L.; Wood, J. D.; Williams, J. L. (2008) Detection of quantitative trait loci for meat quality traits in cattle Animal Genetics, 39 (1): 51–61

 

KEYWORDS: Quantitative trait loci, meat quality, cattle

 

SUMMARY: A whole-genome scan was carried out to detect quantitative trait loci (QTL) affecting sensory, organoleptic, physical and chemical properties of meat. The study used phenotypic data from 235 second-generation cross-bred bull calves of a Charolais × Holstein experimental population. Loin muscle samples were evaluated for yield force, intramuscular fat and nitrogen contents, myofibrillar fragmentation index, haem pigment concentration, moisture content and pH at 24 h postmortem. A sensory assessment was performed on grilled loin and roasted silverside joints by trained panellists. A linear regression analysis based on 165 markers revealed 35 QTL at the 5% chromosome-wide significance level (20 for sensory traits and 15 for physical and chemical traits), five of which were highly significant (F-value: ≥9). The most significant QTL was located on chromosome 6 (with the best likely position at 39 cM) and affected haem pigment concentration. The Holstein allele for this QTL was associated with an increase of 0.53 SD in the haem scores. A QTL for pH24h was identified on chromosome 14 (at 40 cM) and a QTL for moisture content was identified on chromosome 22 (at 21 cM).

 

Masoudi, A.A, Uchida, K., Yokouchi, K., Miyadera, K., Ogawa, H., Sugimoto, Y., Kunieda, T. (2007) Marker-assisted selection for forelimb-girdle muscular anomaly of Japanese Black cattle Animal Science Journal, 78 (6): 672–675

 

KEYWORDS: Marker-assisted selection, forelimb-girdle muscular anomaly, Japanese Black cattle

 

SUMMARY: Forelimb-girdle muscular anomaly is a hereditary disorder of Japanese Black cattle characterized by tremors and astasia caused by hypoplasia of the forelimb-girdle muscles. The locus responsible for this disorder has been mapped on a middle region of bovine chromosome 26. In this study, marker-assisted selection was applied to identify the carriers of this disorder. Four microsatellite markers, DIK4440, BM4505, MOK2602 and IDVGA-59, linked to the disorder locus were genotyped in 37 unaffected offspring of a carrier sire. Transmission of the mutant or wild-type allele of the disorder locus of the sire to the 37 offspring was determined by examining the haplotypes of these markers. The results showed that nine and 18 of the 37 animals possessed the paternally transmitted mutant and wild-type alleles, respectively, and therefore, the nine animals with the mutant allele were identified as carriers.

 

Nkrumah, J. D., Sherman, E. L., Li, C., Marques, E., Crews, Jr., D. H., Bartusiak, R., Murdoch, B., Wang, Z., Basarab, J. A., Moore, S. S. (2007) Primary genome scan to identify putative quantitative trait loci for feedlot growth rate, feed intake, and feed efficiency of beef cattle Journal of Animal Science, 85:3170-3181

 

SUMMARY: The study was conducted to identify QTL for feed intake and feed efficiency of beef cattle by using genotype information from 100 microsatellite markers and 355 SNP genotyped across 400 progeny of 20 Angus, Charolais, or Alberta Hybrid bulls. Traits analyzed include feedlot ADG, daily DMI, feed-to-gain ratio [F:G, which is the reciprocal of the efficiency of gain (G:F)], and residual feed intake (RFI). A mixed model with sire as random and QTL effects as fixed was used. Putative QTLs for ADG were detected across families on chromosomes 5. For DMI, putative QTLs were detected on chromosomes 1. Putative across-family QTLs influencing F:G were detected on chromosomes 3, 5, 7, 11, 16, 17, 22, 24, and 28. Putative QTLs influencing RFI were detected on chromosomes 1, 5, 7, 8, 12, 16, 17, and 26 in the across-family analyses. In addition, a total of 4, 6, 1, and 8 chromosomes showed suggestive evidence (chromosome-wise, P < 0.10) for putative ADG, DMI, F:G, and RFI QTL, respectively. Most of the QTL detected across families were also detected within families, although the locations across families were not necessarily the locations within families, which is likely because of differences among families in marker informativeness for the different linkage groups

 

Nakaoka, H., Narita, A., Ibi, T., Sasae, Y., Miyake, T., Yamada, T., Sasaki, Y. (2007) Effectiveness of adjusting for heterogeneity of variance in genetic evaluation of Japanese Black cattle Journal of Animal Science, 85:2429-2436

 

KEYWORDS: beef cattle, carcass weight, genetic evaluation, heterogeneity of variance, model selection, statistical validation

 

SUMMARY: Heterogeneity of variance among subclasses of an effect is a potential source of bias in genetic evaluation. The objectives of this study were to quantify the heterogeneity of variance in carcass weight in Japanese Black cattle, to develop an adjustment method to account for the heterogeneity, and to evaluate the effectiveness of the method. A total of 96,950 records were collected from steers and heifers slaughtered from 1997 to 2005. These records were grouped into 2,767 farm-market-year-sex subclasses. Fourteen log-linear models for the variances were set up to estimate the heterogeneous phenotypic variances within subclasses. Schwarz’s Bayesian information criterion was used for model selection. The preadjustment of records to a baseline variance was based on maximum likelihood estimates obtained from the selected model. As a result of adjustment, the SD, the CV, and the Gini coefficient for the phenotypic variance decreased by 68.6, 69.8, and 70.1%, respectively. When the top 5% of sires and top 1% of dams were selected, Spearman’s rank correlation coefficients between the adjusted and unadjusted data were 0.95 for the selected sires and 0.78 for the selected dams. The effectiveness of the adjustment was evaluated in terms of the ability to predict breeding values, using the results of the successive genetic evaluations. Mean squared error between the parent averages and actual predicted values of the genetic merit for the sires whose progeny had a carcass record only from 2003 to 2005 was significantly reduced by the adjustment (P < 0.05).

 

McParland, S., Kearney, J. F., Rath, M. Berry, D. P. (2007) Inbreeding Effects on Milk Production, Calving Performance, Fertility, and Conformation in Irish Holstein-Friesians Journal of Dairy Science, 90: 4411-4419

 

KEYWORDS: inbreeding depression, milk, dystocia, fertility

 

SUMMARY: The objective of this study was to determine the effect of inbreeding on milk production, somatic cell count, fertility, survival, calving performance, and cow conformation in Irish Holstein-Friesian pluriparous dairy cows. Inbreeding was included in a linear mixed model as either a class variable or a continuous variable, where higher order polynomials of the latter were also tested in the model as an indicator of nonlinear inbreeding depression. The effects of dam inbreeding and calf inbreeding on calving-related traits were analyzed separately. Inbreeding had a deleterious effect on most of the traits analyzed, although inbreeding depression was sometimes nonlinear or differed significantly across parities. A primiparous animal, 12.5% inbred (i.e., following the mating of noninbred half-sibs), had milk, fat, and protein yields reduced by 61.8, 5.3, and 1.2 kg, respectively; fat and protein concentrations reduced by 0.05 and 0.01%, respectively; and somatic cell scores (i.e., natural log of somatic cell count divided by 1,000) increased by 0.03. The 12.5% inbred animal was also expected to have a 2% greater incidence of dystocia, a 1% greater incidence of stillbirth, a 0.7% greater incidence of male calves, an increase in calving interval of 8.8 d, an increase in age at first calving of 2.5 d, and a reduced survival to second lactation of 4 percentage units. Inbred animals were also taller, narrower, and more angular. Although the effects of inbreeding were statistically significant, they were small and are unlikely to cause great financial loss on Irish dairy farms.

 

De Haas, Y., Janss, L. L. G., Kadarmideen, H. N. (2007) Genetic correlations between body condition scores and fertility in dairy cattle using bivariate random regression models Journal of Animal Breeding and Genetics, 124 (5): 277–285

 

KEYWORDS: Body condition score, dairy cattle, fertility, genetic correlation, random regression

 

SUMMARY: Genetic correlations between body condition score (BCS) and fertility traits in dairy cattle were estimated using bivariate random regression models. BCS was recorded by the Swiss Holstein Association on 22 075 lactating heifers (primiparous cows) from 856 sires. Fertility data during first lactation were extracted for 40 736 cows. The fertility traits were days to first service (DFS), days between first and last insemination (DFLI), calving interval (CI), number of services per conception (NSPC) and conception rate to first insemination (CRFI). A bivariate model was used to estimate genetic correlations between BCS as a longitudinal trait by random regression components, and daughter's fertility at the sire level as a single lactation measurement. Heritability of BCS was 0.17, and heritabilities for fertility traits were low (0.01–0.08). Genetic correlations between BCS and fertility over the lactation varied from: −0.45 to −0.14 for DFS; −0.75 to 0.03 for DFLI; from −0.59 to −0.02 for CI; from −0.47 to 0.33 for NSPC and from 0.08 to 0.82 for CRFI. These results show (genetic) interactions between fat reserves and reproduction along the lactation trajectory of modern dairy cows, which can be useful in genetic selection as well as in management.

 

Sellick, G. S., Pitchford, W. S., Morris, C. A., Cullen, N. G., Crawford, A. M., Raadsma, H. W., Bottema, C. D. K. (2007) Effect of myostatin F94L on carcass yield in cattle Animal Genetics, 38 (5): 440–446.

 

KEYWORDS: Myostatin, F94L, carcass yield, cattle

 

SUMMARY: In this study, a highly significant quantitative trait locus (QTL) for meat percentage, eye muscle area (EMA) and silverside percentage was found on cattle chromosome 2 at 0–15 cM, a region containing the positional candidate gene growth differentiation factor 8 (GDF8), which has the common alias myostatin (MSTN). Loss-of-function mutations in the MSTN gene are known to cause an extreme ‘double muscling’ phenotype in cattle. In this study, highly significant associations of MSTN with cattle carcass traits were found using maternally inherited MSTN haplotypes from outbred Limousin and Jersey cattle in a linkage disequilibrium analysis. A previously reported transversion in MSTN (AF320998.1:g.433C>A), resulting in the amino acid substitution of phenylalanine by leucine at position 94 of the protein sequence (F94L), was the only polymorphism consistently related to increased muscling. Overall, the size of the g.433C>A additive effect on carcass traits was moderately large, with the g.433A allele found to be associated with a 5.5% increase in silverside percentage and EMA and a 2.3% increase in total meat percentage relative to the g.433C allele. The phenotypic effects of the g.433A allele were partially recessive.

 

Ron, M., Weller, J.I. (2007) From QTL to QTN identification in livestock - winning by points rather than knock-out: a review Animal Genetics, 38 (5): 429–439

 

KEYWORDS: QTL, QTN, livestock, review

 

SUMMARY: Many quantitative trait loci (QTL) affecting economic traits in livestock have now been identified. However, the confidence interval (CI) of individual QTL as determined by linkage analysis often spans tens of map units, containing hundreds of genes. Linkage disequilibrium (LD) mapping can reduce the CI to individual map units, but this reduced interval will still contain tens of genes. Methods suitable for model animals to find and validate specific quantitative trait nucleotides (QTN) underlying the QTL cannot be easily applied to livestock species because of their long generation intervals, the cost of maintaining each animal and the difficulty of producing transgenics or ‘knock-outs’. Considering these limitations, successful approaches for identifying QTN in livestock were reviewed and a schematic strategy for QTN determination and verification was outlined. In addition to linkage and LD mapping, the methods include positional cloning, selection of candidate genes, DNA sequencing and statistical analyses. Concordance determination and functional assays are the critical tests for validation of a QTN. A generalized formula for the probability of concordance by chance was provided. Three genes that meet the burden of proof for QTN identification –DGAT1 in cattle, IGF2 in swine and GDF8 in sheep – are discussed in detail.

 

Gernand, E., Waßmuth, R., von Borstel, U.U., König, S. (2007) Heterogeneity of variance components for production traits in large-scale dairy farms Livestock Science, 112 (1-2): 78-89

 

KEYWORDS: Heterogeneous variances; Test day models; Cluster analysis

 

SUMMARY: The aim of this study was to estimate genetic parameters applying fixed regression and random regression test day models for protein yield using subsets stratified by herd size, average production level of herds in test day protein yield, and average age at first calving within herds. The data consisted of 64,394 Holstein cows located in one region in Eastern Germany including 690,553 first lactation test day production records. Estimates of variance components revealed heterogeneity of genetic variances across subsets and the highest additive genetic variances and heritabilities were found in larger herds with high production level and low age at first calving. Special cooperator herds for dairy cattle progeny testing programs will be a common practice in the near future. Suitable selection criteria for cooperator herds should consider genetic parameters, e.g. genetic variances and heritabilities within herds or subsets, to identify genetically superior sires as accurately as possible. As shown in the present study, the two-step cluster analysis is an appropriate method to combine all desirable effects of herd parameters for a final selection of cooperator herds. One cluster included 44 large-scale dairy farms with an average of 638 cows per farm and was also characterised by the highest protein yield, the lowest age at first calving, the highest heritability, and the highest additive genetic variance for test day protein yield within herds

 

Zerabruk, M., Bennewitz, J., Kantanen, J., Olsaker, I., Vangen, O. (2007) Analysis of genetic diversity and conservation priorities for six north Ethiopian cattle breeds Journal of Animal Breeding and Genetics, 124 (4):236–241

 

KEYWORDS: Conservation potential, core set, expected future diversity, extinction probability, marginal diversity

 

SUMMARY: Genetic diversity and conservation potential of six indigenous cattle breeds of north Ethiopia was analysed based on 20 microsatellite markers using core set methods. Expected future diversity (assuming assigned extinction probabilities are valid for the next 20–50 years) were 0.988 ± 0.011 and 0.980 ± 0.010 with expected loss of diversity estimated at 0.02% and 0.74% of current level for the Maximum Variance Total (MVT) and Maximum Variance Offspring (MVO) core sets, respectively. Even though all breeds have contributed to current diversity levels, the Afar and Abergelle breeds only contributed 51% and 62% to the MVT and MVO core sets, respectively, while the Raya breed contributed only 6% and 1.5% to the MVT and MVO core set diversities, respectively. Moreover, prioritizing the six north Ethiopian cattle breeds using the conservation potential obtained from the MVT core set method seems reasonable considering the origin and migration histories of the breeds.

 

Fahey, A. G., Schutz, M. M., Lofgren, D. L., Schinckel, A. P., Stewart, T. S. (2007) Genotype by Environment Interaction for Production Traits While Accounting for Heteroscedasticity Journal of Dairy Science, 90::3889-3899

 

KEYWORDS: heteroscedasticity, heritability, variance quartile

 

SUMMARY: The objective of this study was to investigate the effect of heteroscedasticity (HV) on estimates of heritabilities and genetic correlations for mature-equivalent milk, protein, and fat yield, and lactation-average somatic cell scores of daughters, and to determine if HV affects the ability of sire’s predicted transmitting ability (PTA) to predict daughter production in G and confinement (C) herds. Data consisted of 72,489 records from 35,674 cows in 366 G herds from 11 states, and 117,629 records from 50,963 cows in 373 C herds from the same 11 states plus 1 geographically contiguous state. Herds were divided into variance quartiles (QV1–QV4) based on milk yield. A transformation was used to reduce HV by standardizing the within-herd standard deviation to the average across-herd standard deviation of a base year for each parity, and was similar to the method used in current USDA-DHIA genetic evaluations. Regression of daughter yield on sire PTA showed that PTA overestimated production of all traits in QV1–QV3 and of milk in QV4 of G herds. For C herds, yields of milk in QV1 and QV2, and of protein and fat in QV1 were overestimated, and protein was underestimated in QV4. Reducing HV had little effect on G herds, but for C herds, regression did not differ from unity for milk and protein in QV1 and QV2. For milk, protein, and fat in G, heritabilities were approximately 0.17, 0.17, and 0.19, respectively. The heritabilities for milk, protein, and fat in C herds were approximately 0.16, 0.17, and 0.21, respectively. Genetic correlations between C and G did not suggest a GxE in 3 upper quartiles, but a possible GxE (correlation = 0.21, estimated standard error = 0.22) for the lowest quartile. Reducing HV did not affect estimates of heritabilities or genetic correlations.

 

Lusk, J. L. (2007) Association of single nucleotide polymorphisms in the leptin gene with body weight and backfat growth curve parameters for beef cattle Journal of Animal Science, 85:1865-1872

 

KEYWORDS: Backfat, beef cattle, growth curve, leptin gene, single nucleotide polymorphism

 

SUMMARY: The objective of this study was to investigate the effect of 2 leptin SNP on growth curve parameters for BW and backfat. Two SNP (UASMS2 and R25C) were genotyped on 1,653 cross-bred steers and heifers in a commercial feedlot. Up to 4 serial measures of BW and ultrasound estimates of backfat thickness were taken for each animal from the time of placement on feed to slaughter. The measures were used to estimate growth models that describe changes in BW and backfat thickness as a function of days on feed. Data analysis was carried out by estimating nonlinear mixed models to determine the individual and joint effect of each SNP on growth curve parameters. Brody growth curves were fit to the BW data. Variations in the R25C SNP did not significantly affect growth parameters individually or in combination with the UASMS2 SNP. Variations in the UASMS2 SNP were significant in Brody growth curve parameters for BW growth (P < 0.001). The genotype UASMS2-CC was the heaviest at the beginning of the feeding period and exhibited the largest asymptotic mature BW, but UASMS2-TT cattle exhibited the fastest rate of BW growth. A modified power function was fit to the serial ultrasound backfat measures. Models that included the combined effect of the R25C and UASMS2 SNP provided the best fit to the data. Genotypes differed significantly in power function parameters for backfat growth (P < 0.001). The R25C-CC/UASMS2-TT cattle had the smallest backfat thickness at placement. The genotype R25C-CC/UASMS2-TT exhibited the fastest backfat growth rate, whereas backfat in R25C-CC/UASMS2-CC cattle grew at the slowest rate.

 

Nkrumah, J. D., Keisler, D. H., Crews, Jr., D. H., Basarab, J. A., Wang, Z., Li, C., Price, M. A., Okine, E. K., Moore, S. S. (2007) Genetic and phenotypic relationships of serum leptin concentration with performance, efficiency of gain, and carcass merit of feedlot cattle Journal of Animal Science, 85:2147-2155

 

KEYWORDS: beef cattle, carcass merit, feed efficiency, performance, serum leptin

 

SUMMARY: This study estimated the genetic variation in serum leptin concentration and evaluated the genetic and phenotypic relationships of serum leptin concentration with performance, efficiency of gain, and carcass merit. Serum leptin concentration was moderately heritable (h2 = 0.34 ± 0.13) and averaged 13.91 (SD = 5.74) ng/mL. Sire breed differences in serum leptin concentration correlated well with breed differences in body composition. Consequently, ultrasound backfat (27%), carcass 12th-rib fat (31%), ultrasound marbling (14%), and carcass marbling (15%) were less in Charolais- than Angus-sired steers (P < 0.001). Conversely, carcass LM area (P = 0.05) and carcass lean meat yield (P < 0.001) were greater in Charolais- compared with Angus-sired steers. Steers with greater serum leptin concentration also had greater DMI (P < 0.001), greater residual feed intake (P = 0.04), and partial efficiency of growth (P = 0.01), but did not differ in feed conversion ratio (P > 0.10). Serum leptin concentration was correlated phenotypically with ultrasound backfat (r = 0.41; P < 0.001), carcass 12th-rib fat (r = 0.42; P < 0.001), ultrasound marbling (r = 0.25; P < 0.01), carcass marbling (r = 0.28; P < 0.01), ultrasound LM area (r = –0.19; P < 0.01), carcass LM area (r = –0.17; P < 0.05), lean meat yield (r = –0.38; P < 0.001), and yield grade (r = 0.32; P < 0.001). The corresponding genetic correlations were generally greater than the phenotypic correlations and included ultrasound backfat (r = 0.76 ± 0.19), carcass 12th-rib fat (r = 0.54 ± 0.23), ultrasound marbling (r = 0.27 ± 0.22), carcass marbling (r = 0.76 ± 0.21), ultrasound LM area (r = –0.71 ± 0.19), carcass LM area (r = –0.75 ± 0.20), lean meat yield (r = –0.59 ± 0.22), and yield grade (r = 0.39 ± 0.26).

 

Tellam, R.L. (2007) Capturing benefits from the bovine genome sequence Australian Journal of Experimental Agriculture, 47(9):1039–1050

 

KEYWORDS: cow, ruminant

 

SUMMARY: The bovine genome sequence in ‘draft’ form will be complete in 2007. The availability of the sequence and very large numbers of single nucleotide polymorphisms will have profound effects on livestock production. The dairy industry is well positioned to capture the benefits of this enormous and enabling resource because of its comprehensive databases containing phenotypic and pedigree data for large numbers of animals, intense utilisation of genetics in breeding programs and efficient management of reproductive performance. The bovine genome sequence will assist in the development of novel products, especially value-added products, and markedly enhance the rate of genetic gain in the Australian dairy population

 

Svensson, E. M., Anderung, C., Baubliene, J., Persson, P., Malmström, H., Smith, C., Vretemark, M., Daugnora, L., Götherström, A. (2007) Tracing genetic change over time using nuclear SNPs in ancient and modern cattle Animal Genetics, 38 (4):378–383

 

KEYWORDS: ancient DNA, Bos taurus, genetic diversity, pyrosequencing, selection, single nucleotide polymorphism

 

SUMMARY: Ancient DNA has the potential of adding the dimension of time to genetic studies. With a suitable sample set it should be possible to follow genetic changes over time as they occur. To date, only a limited number of ancient DNA studies that cover a large time span have been published, and all of these studies have used mitochondrial DNA. Here, SNP typing was explored as a way to access ancient coding nuclear genes. By targeting fragments of minimal size, three polymorphic sites were typed in 111 ancient cattle remains spanning some 4000 years. It was shown that there has been a decrease in heterozygosity over time, especially since the late Middle Ages.

 

Alexander, L. J., Geary, T. W., Snelling, W. M., MacNeil M. D. (2007) Quantitative trait loci with additive effects on growth and carcass traits in a Wagyu-Limousin F2 population Animal Genetics, 38 (4):413–416

 

KEYWORDS: Quantitative trait loci with additive effects on growth and carcass traits in a Wagyu-Limousin F2 population

 

SUMMARY: A whole-genome scan for carcass traits [average daily gain during the pre-weaning, growth and finishing periods; birth weight; hot carcass weight and longissimus muscle area (LMA)] was performed on 328 F2 progeny produced from Wagyu × Limousin-cross parents derived from eight founder Wagyu bulls. Nine significant (P ≤ 0.05) and four suggestive (P ≤ 0.1) QTL affecting seven growth and carcass traits were identified. Significant QTL were located on bovine chromosomes 2, 4, 7, 9, 12, 16, 17 and 29. A QTL previously reported on chromosome 2 for LMA was also detected in this study.

 

Cheong, H.S., Yoon, D., Kim, L.H., Park, B.L., Lee, H.W., Han, C.S., Kim, E.M., Cho, H., Chung, E.R., Cheong, I., Shin H.D. (2007) Titin-cap (TCAP) polymorphisms associated with marbling score of beef Meat Science, 77 (2):257-263

 

KEYWORDS: TCAP; Marbling score; Cold carcass weight; Polymorphism

 

SUMMARY: Marbling score (MS) is the major qualitative trait that affects carcass quality in beef cattle. In this study, the association between genetic polymorphisms of the titin-cap gene (TCAP) and carcass traits in Korean native cattle was examined. By direct DNA sequencing in 24 unrelated Korean cattle, five sequence variants were identified in 1.2 kb of TCAP. Among them, four common polymorphic sites were selected for genotyping in the beef cattle (n = 437). Pair-wise linkage analysis with four polymorphisms showed strong linkage disequilibrium (LD), and three major haplotypes (freq. > 0.1) were constructed. Statistical analysis revealed that polymorphisms in intron1 (g.346G > A) and exon2 (g.592-597CTGCAG[Leu-Gln]insdel) showed significant association with marbling score (Pcor. = 0.003 and 0.02, respectively). One haplotype, ht2[C-G-G-del], also showed significant association with MS (Pcor. = 0.0004).

 

Gautier, M., Capitan, A., Fritz, S., Eggen, A., Boichard, D., Druet, T. (2007) Characterization of the DGAT1 K232A and Variable Number of Tandem Repeat Polymorphisms in French Dairy Cattle Journal of Dairy Science, 90:2980-2988.

 

KEYWORDS: quantitative trait locus, dairy trait, acyl-CoA:diacylglycerol acyltransferase gene (DGAT1), variable number of tandem repeats

 

SUMMARY: A quantitative trait locus (QTL) underlying different milk production traits has been identified with a high significance threshold value in the genomic region containing the acylCoA:diacylglycerol acyltransferase (DGAT1) gene, in the 3 main French dairy cattle breeds: French Holstein, Normande, and Montbéliarde. Previous studies have confirmed that the K232A polymorphism in DGAT1 is responsible for a major QTL underlying several milk production traits in Holstein dairy cattle and several other bovine breeds. In this study, the frequency of the 2 alternative alleles, K and A, of the K232A polymorphism was estimated. Although the K allele segregates in French Holstein and Normande breeds with a similar effect on production traits, the existence of additional mutations contributing to the observed QTL effect is strongly suggested in both breeds by the existence of sires heterozygous at the QTL but homozygous at the K232A polymorphism. One allele at a variable number of tandem repeats (VNTR) locus in the 5' noncoding region of DGAT1 has been recently proposed as a putative causative variant. This marker was found to present a high mutation rate of 0.8% per gamete and per generation.

 

Smith, T., Domingue, J. D., Paschal, J. C., Franke, D. E., Bidner, T. D., Whipple, G. (2007) Genetic parameters for growth and carcass traits of Brahman steers Journal Animal Science, 85:1377-1384

 

KEYWORDS: Brahman steer, carcass trait, genetic parameter

 

SUMMARY: Spring-born purebred Brahman bull calves (n = 467) with known pedigrees, sired by 68 bulls in 17 private herds in Louisiana, were purchased at weaning from 1996 through 2000 to study variation in growth, carcass, and tenderness traits. An animal model was used to estimate heritability, genetic correlations, and sire EPD. Relatively high heritability estimates were found for BW at slaughter (0.59 ± 0.16), HCW (0.57 ± 0.15), LM area (0.50 ± 0.16), yield grade (0.46 ± 0.17), calpastatin enzyme activity (0.45 ± 0.17), and carcass quality grade (0.42 ± 0.16); moderate heritability estimates were found for hump height (0.38 ± 0.16), marbling score (0.37 ± 0.16), backfat thickness (0.36 ± 0.17), feedlot ADG (0.33 ± 0.14), 7-d shear force (0.29 ± 0.14), and 14-d shear force (0.20 ± 0.11); relatively low heritability estimates were found for skeletal maturity (0.10 ± 0.10), lean maturity (0.00 ± 0.07), and percent KPH (0.00 ± 0.07). Most genetic correlations were between –0.50 and +0.50. Other genetic correlations were 0.74 ± 0.27 between calpastatin activity and 7-d shear force, 0.72 ± 0.25 between calpastatin activity and 14-d shear force, (0.90 ± 0.30 between yield grade and 7-d shear force, and –0.82 ± 0.27 between backfat thickness and 7-d shear force.

 

Oyama, K., Nojima, M., Shojo, M., Fukushima, M., Anada, K., Mukai, F. (2007) Effect of sire mating patterns on future genetic merit and inbreeding in a closed beef cattle population Journal of Animal Breeding and Genetics, 124 (2): 73–80

 

KEYWORDS: Landrace, Large White, meat production, MYOD, Pig

 

SUMMARY: Alternative breeding strategies were simulated based on the population structure of the Tajima strain of Japanese Black cattle. An analysis of the population structure revealed that some sires up to 20 years of age have been used in Tajima. In addition, 95% of newborn calves were the progeny of only 20 sires, and their mating frequencies were significantly skewed. The current average inbreeding coefficient and founder genome equivalents of the strain were estimated to be 0.199 and 2.25, respectively. Average inbreeding coefficient is expected to reach 0.394 within 27 years. Thus, different breeding strategies were assessed for their effect on the level of inbreeding and average genetic merit. Strategies were compared that (1) halve the sire service period, (2) double the number of mating sires and (3) lower the skewed sire mating frequency and optimize the frequency for weighted genetic merit and diversity. Reducing the service period yielded a 7.0–12.0% reduction in the rate of inbreeding while maintaining almost the same genetic gain. Increasing the number of sires resulted in a 19.3–21.3% reduction in inbreeding with a corresponding 1.6–8.4% reduction in gain. The rates of inbreeding from the optimized strategies decreased as the weight on genetic diversity increased. However, a strategy that emphasized only genetic gain yielded lower gain than other strategies because the strategy allowed only one sire to mate, resulting in reduced genetic variance and low accuracy of genetic evaluation. In contrast, a strategy with no emphasis on genetic gain when determining mating frequency resulted in reductions of 16.0% and 63.2% in genetic gain and inbreeding, respectively.

 

Meyer, K. (2007) Multivariate analyses of carcass traits for Angus cattle fitting reduced rank and factor analytic models Journal of Animal Breeding and Genetics, 124 (2): 50–64

 

KEYWORDS: Beef cattle, carcass traits, genetic parameters, principal components, reduced rank

 

SUMMARY: Multivariate analyses of carcass traits for Angus cattle, consisting of six traits recorded on the carcass and eight auxiliary traits measured by ultrasound scanning of live animals, are reported. Analyses were carried out by restricted maximum likelihood, fitting a number of reduced rank and factor analytic models for the genetic covariance matrix. Estimates of eigenvalues and eigenvectors for different orders of fit are contrasted and implications for the estimates of genetic variances and correlations are examined. Results indicate that at most eight principal components (PCs) are required to model the genetic covariance structure among the 14 traits. Selection index calculations suggest that the first seven of these PCs are sufficient to obtain estimates of breeding values for the carcass traits without loss in the expected accuracy of evaluation.

 

Cole, J. B., Wiggans,  G. R.,  VanRaden, P. M., Miller, R.H. (2007) Stillbirth (Co)Variance Components for a Sire-Maternal Grandsire Threshold Model and Development of a Calving Ability Index for Sire Selection Journal of Dairy Science, 90: 2489-2496

 

KEYWORDS: calving ability index, stillbirth, threshold model, variance component

 

SUMMARY: (Co)variance components for stillbirth in US Holsteins were estimated under a sire-maternal grandsire threshold model using subsets of data from the national calving ease database. Stillbirth was coded as a binomial trait indicating whether the calf was alive 48 h postpartum. Records were selected for calves whose sire and maternal grandsire (MGS) were among the 2,600 most frequently appearing bulls. Herd-years were required to contain at least 20 records and only single births were used. Six sample datasets of approximately 250,000 records each were created by randomly selecting herd codes. Quasi-REML and Bayesian approaches were used to estimate (co)variance components from each sample. The model included fixed year-season, parity-sex, birth year group of sire, and birth year group of MGS effects and random herd-year, sire, MGS, and residual effects. Quasi-REML and Bayesian analyses produced similar results, although the Bayesian estimates were slightly larger. Marginal posterior means (and standard deviations) from the Bayesian analysis averaged 0.0085 (0.0015), 0.0181 (0.0020), 0.0872 (0.0538), and 0.00410 (0.0001) for sire, MGS, and herd-year variances and the sire-MGS covariance, respectively. Mean direct and maternal heritabilities were 0.030 (0.003) and 0.058 (0.005), respectively, and the mean genetic correlation between the 2 effects was –0.02 (0.16).

 

Cole, J. B., Wiggans,  G. R.,  VanRaden, P. M. (2007) Genetic Evaluation of Stillbirth in United States Holsteins Using a Sire-Maternal Grandsire Threshold Model Journal of Dairy Science, 90: 2480-2488

 

KEYWORDS: sire-maternal grandsire model, stillbirth, threshold model

 

SUMMARY: A sire-maternal grandsire threshold model was used for genetic evaluation of stillbirth in US Holsteins. Calving ease and stillbirth records for herds reporting at least 10 dead calves were extracted from the Animal Improvement Programs Laboratory database. About half of the 14 million calving ease records in the database had a known livability score. Calf livability scores of 2 and 3, representing calves born dead and calves that died within 48 h of parturition, respectively, were combined into a single category. The model included effects of herd-year, year-season, parity-sex, sire, birth year group of sire, maternal grandsire (MGS), and birth year group of MGS. Herd-year, sire, and MGS were random effects. Mean predicted transmitting abilities, expressed as the expected percentage of stillbirths, were 7.9 and 8.6 for direct and maternal stillbirths, respectively. Mean reliabilities for both the direct and maternal effects were 45%. Correlations among domestic and Interbull stillbirth solutions on the underlying scale for bulls with at least 90% reliability ranged from 0.63 to 0.90 across countries for direct stillbirths and from 0.69 to 0.96 for maternal stillbirths, indicating that results were generally consistent with those from other countries

 

VanRaden, P. M., Tooker, M. E., Cole, J. B., Wiggans,  G. R.,  Megonigal, J. H.  Jr. (2007) Genetic Evaluations for Mixed-Breed Populations Journal of Dairy Science, 90:2434-2441

 

KEYWORDS: genetic evaluation, multibreed, cross-breeding

 

SUMMARY: An all-breed animal model was developed for routine genetic evaluations of US dairy cattle. Data sets from individual breeds were combined, and records from crossbred cows were included. Six traits were analyzed, which were milk, fat, protein, somatic cell score, productive life, and daughter pregnancy rate. Programs were modified to account for general heterosis, to group unknown parents separately by breed, to adjust variances separately by breed, and to adjust data to a 36-mo age equivalent instead of a mature equivalent. Convergence rate of the all-breed model was similar to that of the previous within-breed animal model. Estimated breed differences were similar to those obtained previously from phenotypic breed means or from studies of crossbred cows and their herd-mates. Genetic evaluations from the all-breed and within-breed systems had high correlations: >0.99 for recent Holsteins and slightly <0.99 for other breeds. Predicted transmitting abilities will be converted back to the within-breed bases for purebred animals and to the breed of sire base for crossbred animals so that most purebred breeders will not be affected by the change to a multibreed model. Evaluations of crossbred animals from the multibreed model can include accurate information for both parents.

 

B. Heringstad, B., Klemetsdal, G., Steine, T. (2007) Selection Responses for Disease Resistance in Two Selection Experiments with Norwegian Red Cows Journal of Dairy Science, 90:2419-2426

 

KEYWORDS: clinical mastitis, correlated selection response, dairy cattle, disease resistance

 

SUMMARY: Genetic trends for clinical mastitis (CM), ketosis (KET), retained placenta (RP), and 305-d protein yield (PY305) were calculated for 2 Norwegian dairy cattle selection experiments. The first experiment, accomplished from 1978 to 1989, included groups selected for high (HMP) and low milk production (LMP). The second experiment started in 1989 and included selection for high protein yield (HPY) and low mastitis frequency (LCM). In both experiments proven sires from the active breeding program of Norwegian Red were used as sires. To take into account that selection of sires was external to the experiment, all available data from the Norwegian Red population, including disease records for 2.7 million first-lactation cows, were analyzed with a multivariate animal model. Estimated breeding values for cows in the experiments were extracted from this analysis to calculate genetic trends in the selection groups. Genetic trends for PY305 were positive for the HMP and HPY groups, and negative for LMP and LCM. The HMP group showed increasing genetic trends for all 3 diseases, arguably a correlated response after selection for increased milk production, whereas the LCM group showed decreasing genetic trends for CM, KET, and RP. After 5 cow-generations the genetic difference between HPY and LCM was 10 percentage units CM, 1.5 percentage units KET, and 0.5 percentage units RP

 

López de Maturana, E., Legarra, A., Varona, L., Ugarte, E. (2007) Analysis of Fertility and Dystocia in Holsteins Using Recursive Models to Handle Censored and Categorical Data Journal of Dairy Science, 90:2012-2024

 

KEYWORDS:  recursive model, genetic parameter, fertility, dystocia

 

SUMMARY: A method based on the analysis of recursive multiple-trait models was used to estimate genetic and phenotypic relationships of calving ease (CE) with fertility traits and to analyze whether dystocia negatively affects reproductive performance in the next reproductive cycle. Data were collected from 1995 through 2002, and contained 33,532 records of CE and reproductive data of 17,558 Holstein cows distributed across 560 herds. Fertility traits considered were days open (DO), days to first service, number of services per pregnancy (NINS), and outcome of first insemination (OFI). Four bivariate sire and sire-maternal grandsire models were used for the analyses. Threshold models were used for CE and OFI. To consider that CE affects fertility and the genetic determination of CE and fertility traits, recursive models were applied, which simultaneously considered CE as a fixed effect on fertility performance and the existence of a genetic correlation between CE and fertility traits. The effects of CE score 3 (difficult birth) with respect to score 1 (no problem) for days to first service, DO, NINS, and OFI were 8 d, 31 d, 0.5 services, and – 12% success at first insemination, respectively. These results showed poorer fertility after dystocia. Genetic correlations between genetic effects of fertility traits and CE were close to zero, except for the genetic correlations between direct effects of DO and CE, which were positive, moderate, and statistically different from 0 (0.47 ± 0.24)

 

Stoop, W. M., Bovenhuis, H., van Arendonk, J. A. M. (2007) Genetic Parameters for Milk Urea Nitrogen in Relation to Milk Production Traits Journal of Dairy Science, 90:1981-1986

 

KEYWORDS: dairy cattle, genetic parameter, milk yield, urea

 

SUMMARY: The aim of this study was to estimate genetic parameters for test-day milk urea nitrogen (MUN) and its relationships with milk production traits. Three test-day morning milk samples were collected from 1,953 Holstein-Friesian heifers located on 398 commercial herds in the Netherlands. Each sample was analyzed for somatic cell count, net energy concentration, MUN, and the percentage of fat, protein, and lactose. Genetic parameters were estimated using an animal model with covariates for days in milk and age at first calving, fixed effects for season of calving and effect of test or proven bull, and random effects for herd-test day, animal, permanent environment, and error. Coefficient of variation for MUN was 33%. Estimated heritability for MUN was 0.14. Phenotypic correlation of MUN with each of the milk production traits was low. The genetic correlation was close to zero for MUN and lactose percentage (–0.09); was moderately positive for MUN and net energy concentration of milk (0.19), fat yield (0.41), protein yield (0.38), lactose yield (0.22), and milk yield (0.24), and percentage of fat (0.18), and percentage of protein (0.27); and was high for MUN and somatic cell score (0.85). Herd-test day explained 58% of the variation in MUN, which suggests that management adjustments at herd-level can reduce MUN

 

König, S., Lessner, S., Simianer, H. (2007) Application of Controlling Instruments for Improvements in Cow Sire Selection Journal of Dairy Science, 90:1967-1980

 

KEYWORDS: breeding program, selection intensity, controlling cow sire selection

 

SUMMARY: National estimated breeding values of bulls from 1998 through 2006 from 12 different German artificial insemination (AI) organizations were used to determine the differences in expected and realized selection intensities for cow sire selection, considering the total merit index as well as subindexes for production, conformation, somatic cell count, fertility, and functional herd life. The expected selection intensity was derived from a Gaussian distribution and from the replacement rate describing the percentage of bulls graduated as cow sires from the total amount of progeny-tested young bulls within the AI organization and by birth year. A low replacement rate of cow sires was associated with relatively high realized selection intensities for the total merit, production, and conformation indexes, but was not related to the somatic cell count, fertility, and functional herd life indexes. The controlling value, defined as the ratio of realized to expected selection intensities, indicates the effectiveness of cow sire selection for different traits. Low controlling values suggest improvements in the step of cow sire selection. Significant differences were detected in expected selection intensities, realized selection intensities, and controlling values for the total merit, production, and conformation indexes between AI organizations and birth years of bulls. Artificial insemination organizations applying well-defined breeding policies were successful in the national competition when evaluated according to the national top lists for the respective indexes, regardless of the active population size.

 

Cardoso, F. F., Rosa, G. J. M., Tempelman, R. J. (2007) Accounting for outliers and heteroskedasticity in multibreed genetic evaluations of postweaning gain of Nelore-Hereford cattle Journal of Animal Science, 85:909-918

 

KEYWORDS: Bayesian inference, beef cattle, genetic evaluation, heteroskedasticity, multibreed, robust model

 

SUMMARY: The objectives of this study were to demonstrate the utility of hierarchical Bayesian models combining residual heteroskedasticity with robustness for outlier detection and muting and to evaluate the effects of such joint modeling in multibreed genetic evaluations. A 3 x 2 factorial specification of 6 residual variance models based on several distributional (Gaussian, Student’s t, or Slash) and variability (homoskedastic or heteroskedastic) assumptions were used. To illustrate the utility of the 2 robust distributional specifications (Student’s t and Slash) for outlier detection and muting, 3 records from the same contemporary group (an extreme residual outlier, a mild residual outlier, and a near-zero residual) were chosen for further study. The posterior densities of the corresponding weighting variables of these records were used to assess their degree of Gaussian outlyingness and the ability of the robust models to mute the effects of deviant records. The Student’s t heteroskedastic provided the best-fit model among the 6 specifications and was preferred for genetic merit inference. Kendall rank correlations of the posterior means of the additive genetic effects of the animals, used to compare the selection order of the Student’s t and Gaussian models, were reasonably high, ranging from 0.83 to 0.91 and from 0.89 to 0.95 for the homoskedastic and the heteroskedastic versions, respectively. When considering only animals ranked in the top 10% by the customary Gaussian homoskedastic model, these rank correlations were reduced considerably, ranging from 0.29 to 0.57 and from 0.72 to 0.85 between the 2 residual densities within the homoskedastic and heteroskedastic versions, respectively. Rank correlations between the homoskedastic and heteroskedastic versions within each of the Gaussian and Student’s t error models tended to be smaller, with a range from 0.68 to 0.90 across all animals and from 0.28 to 0.67 for animals ranked in the top 10%.

 

A. L. Van Eenennaam, A.L., Li, J., Thallman, R. M., Quaas, R. L., Dikeman, M. E., Gill, C. A., Franke, D. E., Thomas, M. G. (2007) Validation of commercial DNA tests for quantitative beef quality traits Journal of  Animal Science, 85:891-900

 

KEYWORDS: beef quality, commercial DNA test, genetic marker, validation

 

SUMMARY: Validation of the quality grade test (GeneSTAR Quality Grade) was carried out on 400 Charolais x Angus crossbred cattle, and validation of the tenderness tests (GeneSTAR Tenderness and Igenity Tender-GENE) was carried out on over 1,000 Bos taurus and Bos indicus cattle. The GeneSTAR Quality Grade marker panel is composed of 2 markers (TG5, a SNP upstream from the start of the first exon of thyroglobulin, and QG2, an anonymous SNP) and is being marketed as a test associated with marbling and quality grade. In this validation study, the genotype results from this test were not associated with marbling score; however, the association of substituting favorable alleles of the marker panel with increased quality grade (percentage of cattle grading Choice or Prime) approached significance (P 0.06), mainly due to the effect of 1 of the 2 markers. The GeneSTAR Tenderness and Igenity TenderGENE marker panels are being marketed as tests associated with meat tenderness, as assessed by Warner-Bratzler shear force. These marker panels share 2 common µ-calpain SNP, but each has a different calpastatin SNP. In both panels, there were highly significant (P < 0.001) associations of the calpastatin marker and the µ-calpain haplotype with tenderness. The genotypic effects of the 2 tenderness panels were similar to each other, with a 1 kg difference in Warner-Bratzler shear force being observed between the most and least tender genotypes

 

Kühn, Ch., Weikard, R. (2007) An investigation into the genetic background of coat colour dilution in a Charolais × German Holstein F2 resource population Animal Genetics, 38 (2): 109–113

 

KEYWORDS:  Cattle, coat colour, dilution, SILV

 

SUMMARY: The molecular background of many loci affecting coat colour inheritance in cattle is still incompletely characterized, although it is known that coat colour results from the joint effects of several loci, e.g. agouti, extension and dilution. Dilution alleles are responsible for a dilution effect on the original coat colour of an individual, which is determined by the agouti and extension loci. Different loci affecting dilution of pigment are suggested in Charolais (Dc) and Simmental (Ds). In this study, 133 animals from an F2 full-sib resource population generated from a cross of Charolais and German Holstein were scored for the coat colour dilution phenotype to enable chromosomal mapping of the Dc mutation. Linkage analysis covering all autosomes revealed a significant linkage of the dilution phenotype with microsatellite markers on bovine chromosome 5. No recombination was observed between marker ETH10 and the Dc locus. Positional and functional information identified the bovine silver homolog (SILV) gene as a candidate for the Dc mutation. Results from comparative sequencing of the SILV gene in individuals with different dilution coat colour phenotypes confirmed the presence of a c.64G>A non-synonymous mutation, which had previously been identified in the Charolais breed.

 

Steinbock Lena, Kjell Johansson, Anna Näsholm, Britt Berglund, Jan Philipsson. 2006. "Genetic effects on stillbirth and calving difficulty in Swedish Red dairy cattle at first and second calving". Acta Agriculturae Scandinavica, Section A-Animal Science, 56 (2): 65 – 72

 

KEYWORDS: Dairy cattle, direct and maternal genetic effects, genetic evaluation

 

SUMMARY: In Swedish Red (SRB) dairy cattle, genetic effects on stillbirth and calving difficulty were studied in 804,268 first- and 673,150 second-calvers. Uni- and bivariate linear sire-maternal grandsire models were used to analyse calving data gathered between 1985 and 2000. Mean incidences of stillbirth were low and differed little between first and second parity, 3.6% vs. 2.5%. At first calving, the heritability of stillbirth on the visible scale was 0.7–1.3% for the direct effect and 0.5–0.9% for the maternal effect. For calving difficulty, the heritabilities were around 2.5% and 1.8–2.1% for direct and maternal effects, respectively. At second calving the corresponding heritabilities for the two traits were of the same order as at first parity, albeit somewhat lower for stillbirth. The genetic correlations between first and second calving results were around 0.8 for direct and maternal effects in stillbirth and around 0.7 for calving difficulty. Univariate models for first and second calvings, analysed separately and together in a repeatability model, were compared with a bivariate model which was assumed to be the most correct. The correlations between bulls’ transmitting abilities for stillbirth were 0.94–0.96 between results for first calving analysed with a bivariate model and results from the repeatability model. It was concluded that calving traits at first and second parities could be treated approximately as the same trait. Bivariate analyses, or a repeatability model, including calving results for both heifers and cows should be preferred in genetic evaluations of SRB bulls as sires and maternal grandsires

 

Negussie Enyew, Minna Koivula, Esa A. Mäntysaari. 2006. "Genetic parameters and single versus multi-trait evaluation of udder health traits". Acta Agriculturae Scandinavica, Section A-Animal Science, 56 (2): 73 – 82

 

KEYWORDS: Dairy cattle, clinical mastitis, genetic parameters, genetic evaluation, somatic cell score

 

SUMMARY: Genetic parameters were estimated for lactation average somatic cell score (SCS) and clinical mastitis (CM) for the first three lactations of multiparous Finnish Ayrshire cows. A multi-trait linear sire model was used for estimation of covariance components, and the efficiencies of single- versus multi-trait multi-lactation (MT) sire evaluations were compared. Heritability of SCS and CM in the first three lactations ranged from 0.11 to 0.13 and 0.02 to 0.03, respectively. Within lactation, genetic correlations between SCS and CM ranged from 0.68 to 0.72. Within both traits, across-lactation genetic correlations were lowest between 1 and 3, and highest between 2 and 3, with estimates ranging from 0.75 to 0.86 and from 0.81 to 0.98 for CM and SCS, respectively. Residual and phenotypic correlations were low and ranged from 0.09 to 0.13 and from 0.10 to 0.13, respectively. The absolute difference between genetic and residual correlations was from 0.5 to 0.6. Within-lactation genetic correlations between traits that are much less than unity suggest a multi-trait model for genetic evaluation of mastitis resistance. Comparison of model prediction performance between single-trait (ST) and MT models using a data splitting method showed that the MT model was more stable in predicting breeding values in future records of animals. Especially, for young sires and CM, the SD of EBVs from the MT model was 14 to 23% higher than the ST model, indicating more effective use of information in terms of revealing more genetic variation.

 

Nielsen H. M., A. F. Groen, S. Østergaard, P. Berg. 2006. "A stochastic model for the derivation of economic values and their standard deviations for production and functional traits in dairy cattle". Acta Agriculturae Scandinavica, Section A-Animal Science, 56 (2): 16 – 32

 

KEYWORDS: Milk production, health traits, breeding objective

 

SUMMARY: The objective of this paper was to present a model of a dairy cattle production system for the derivation of economic values and their standard deviations for both production and functional traits under Danish production circumstances. The stochastic model used is dynamic, and simulates production and health in a dairy herd. Because of indirect effects between traits, the phenotypic levels of (related) traits can change as a result of genetic changes. Economic values for milk production and body weight were 0.28 and −0.76 €/kg per cow-year respectively. For incidence of milk fever, mastitis, retained placenta and laminitis economic values were -402.1, -162.5, -79.0 and -210.2 €/ incidence per cow-year. The economic values for involuntary culling rate, stillbirth and conception rate were –6.66, −1.63, and 1.98 €/% per cow-year, respectively and the economic value for days from calving to first heat was −0.94 €/day per cow-year. Standard deviations of economic values expressing variation in realised profit of a farm before and after a genetic change were computed using a linear Taylor series expansion. Expressed as coefficient of variation, standard deviations of economic values based on 1000 replicates ranged between 0.07 (milk production) to 16 (retained placenta).

 

Kamiński S., P. Brym, A. Ruść, E. Wójcik, A. Ahman, R. Mägi. 2006. "Associations Between Milk Performance Traits in Holstein Cows and 16 Candidate SNPs Identified by Arrayed Primer Extension (APEX) Microarray". Animal Biotechnology, 17(1): 1– 11

 

KEYWORDS: Dairy cattle, Milk performance, SNP, Microarray, APEX

 

SUMMARY: An oligonucleotide microarray—which allows for parallel genotyping of many SNPs in genes involved in cow milk protein biosynthesis—was used to identify which of the 16 candidate SNPs are associated with milk performance traits in Holstein cows. Four hundred cows were genotyped by the developed and validated microarray. Significant associations were found between four single SNPs, namely DGAT1 (acyloCoA:diacylglycerol acyltransferase), LTF (lactoferrin), CSN3 (kappa-casein), and GHR (growth hormone receptor) and with fat and protein yield and percentage. Many significant associations between combined genotypes (two SNPs) and milk performance traits were found. The associations between the combined genotypes DGAT1/LTF and DGAT1/LEPTIN analyzed traits are presented as examples.The microarray based on APEX (Arrayed Primer Extension) is a fast and reliable method for multiple SNP analysis of potential application in marker-assisted selection. After further development, the chip may prospectively be used for dairy cattle paternity analysis and evolutionary studies.

 

Neill John D., Julia F. Ridpath, Elizabeth Liebler-Tenorio. 2006. "Global Gene Expression Profiling of Bovine Immature B Cells using Serial Analysis of Gene Expression". Animal Biotechnology, 17(1): 21 – 31

 

KEYWORDS: SAGE, Peyer's Patchi, B cell receptor, B cell function

 

SUMMARY: The Peyer's patches of the small intestine are important sites of antigen processing. The follicles of the Peyer's patches receive the antigen transported by the M cells at the mucosal surface and then play a major role in development of both protective humoral and mucosal immune responses. Serial analysis of gene expression (SAGE) was employed to derive the global gene expression profile of B lymphocytes isolated from the IPPF. Analysis of the SAGE data revealed the identity of genes and the level to which they are expressed by IPPF B lymphocytes. This analysis indicated that they were metabolically active and that the transcripts encoding proteins necessary for a response to antigen presentation were expressed. These transcripts included the B cell receptor components CD76a and b (Ig-alpha and Ig-beta) and accessory c-Src family kinases Lyn and Blk. Furthermore, many of the positive and negative regulators, and accessory proteins that are necessary for B cell antigen receptor signaling were identified. Also present were transcripts encoding interleukins and their cognate receptors. Overall, this SAGE analysis yielded a global picture of gene expression in IPPF B lymphocytes and provides a starting point for the comparison of gene expression in further functional studies.

 

Daly M., P. Ross, L. Giblin, F. Buckley. 2006. "Polymorphisms within the Lactoferrin Gene Promoter in Various Cattle Breeds Animal Biotechnology, 17(1): 33 – 42

 

KEYWORDS: Bovine, Lactoferrin (Lf), Promoter, Single nucleotide polymorphism (SNP)

 

SUMMARY: Lactoferrin (Lf) is an iron-binding protein and belongs to the serum transferrin family. It has broad spectrum antimicrobial action, and it is found in exocrine secretions including milk. The sequence of the bovine lactoferrin gene promoter was analyzed in five different cattle breeds (Holstein Friesian, New Zealand Holstein, Montebéliard, Normande, and Norwegian Red) to determine the extent of polymorphic variation, which exists in this region both within and across cattle breeds. Fifteen different single nucleotide polymorphisms (SNPs) were identified throughout this region. Numerous polymorphisms were found throughout the Holstein Friesian, New Zealand Holstein, Montebéliard, and Normande populations. The most frequently encountered polymorphism found in all breeds was at position −28, which is immediately proximal to the TATA box of the promoter. The most variable base position was −131, which included three types of heterozygotes including a single base deletion in one allele, and three homozygote variants. This polymorphism occurs in a putative transcription factor binding site, for the nuclear factor of activated T cells (NF-ATc). A unique polymorphism was identified in one Normande animal, and three polymorphisms were found in one Montebéliard animal. In general, Norwegian Red cattle displayed fewer SNPs than other breeds. Most nucleotide changes in these animals were within the 190 base pairs of the transcription start point, with the exception of an insertion seen in three animals at position −478. In conclusion, SNPs were found in abundance throughout this regulatory region. Whether or not these polymorphisms have an effect on the regulation of the bovine lactoferrin gene is yet to be elucidated. However, the identification of lactoferrin promoter variants may serve as a marker for healthier animals, thereby accelerating the improvement of animals through breeding

 

Shi Xiju, Chun Xia, Baoliang Pan, Ming Wang. 2006. "Interferon-α Genes from Bos and Bubalus bubalus". Animal Biotechnology, 17(1): 59 – 72

 

KEYWORDS: Bos and Bubalus bubalus, Interferon-α subtypes, Sequence comparison, Antiviral activity

 

SUMMARY: Interferon-α genes were cloned from six breeds of three species of two genera (three Chinese native cattle breeds of yellow cattle, wild yak and HuanHu domestic yak, one European breed of Holstein cow, and two water buffalo breeds of FuAn water buffalo and FuZhong water buffalo) by direct PCR. The PCR products were directly inserted into the expression vector to be sequenced and expressed. Sequence analysis showed that IFN-α genes of six clones were composed of 498 nucleotides, encoding a mature polypeptide with 166 amino acids. Compared with the published BoIFN-α subtypes, the IFN-α gene of Holstein cow had only one point mutation with the BoIFN-αA subtype. The IFN-α gene of yellow cattle was similar to the BoIFN-αD subtype with amino acid identity of 97.0% and may be considered as a new subtype, namely, BoIFN-αD1. The other four IFN-α genes, cloned from wild yak and HuanHu domestic yak, FuAn water buffalo, and FuZhong water buffalo, represented four new subtypes, namely, BoIFN-αI, BoIFN-αJ, BuIFN-α1, and BuIFN-α2, respectively. Each of the six clones was expressed in E. coli with molecular weight of ∼ 20kDa by SDS-PAGE and Western blot analyses. Antiviral activity assays showed that the six recombinant IFN-α (rIFN-α) all exhibited 1000 times higher antiviral activity in the MDBK/VSV cell line than in the CEF/VSV one. Moreover, the rIFN-αs could inhibit infectious bovine rhinotracheitis virus replication in the MDBK cell line using CPE inhibition method. The results suggested that rIFN-αs a potential agent for clinical application against virus diseases in cattle industry.

 

Wunderlich, K. R., Abbey, C. A., Clayton, D. R., Song, Y., Schein, J. E., Georges, M., Coppieters, W., Adelson, D. L., Taylor, J. F., Davis, S. L., Gill, C. A. 2006. "A 2.5-Mb contig constructed from Angus, Longhorn and horned Hereford DNA spanning the polled interval on bovine chromosome 1". Animal Genetics, 37 (6): 592-594.

 

KEYWORDS: BAC contig, bovine chromosome 1, polled STS

 

SUMMARY: The polled locus has been mapped by genetic linkage analysis to the proximal region of bovine chromosome 1. As an intermediate step in our efforts to identify the polled locus and the underlying causative mutation for the polled phenotype, we have constructed a BAC-based physical map of the interval containing the polled locus. Clones containing genes and markers in the critical interval were isolated from the TAMBT (constructed from Angus and Longhorn genomic DNA) and CHORI-240 (constructed from horned Hereford genomic DNA) BAC libraries and ordered based on fingerprinting and the presence or absence of 80 STS markers. A single contig spanning 2.5 Mb was assembled. Comparison of the physical order of STSs to the corresponding region of human chromosome 21 revealed the same order of genes within the polled critical interval. This contig of overlapping BAC clones from horned and polled breeds is a useful resource for SNP discovery and characterization of positional candidate genes.

 

Hastings, N., Donn, S., Derecka, K., Flint, A. P., Woolliams, J. A. 2006. "Polymorphisms within the coding region of the bovine luteinizing hormone receptor gene and their association with fertility traits". Animal Genetics, 37 (6): 583-585.

 

KEYWORDS: bovine, fertility, LHCGR, luteinizing hormone receptor

 

SUMMARY: Mutations within a number of genes have been associated with variations in fertility in various mammals. However, to date there have been no such associations reported for cattle. Herein, we describe three single nucleotide polymorphisms (SNPs) in the luteinizing hormone/ choriogonadotropin receptor gene of cattle (Bos taurus). These polymorphisms include two missense mutations and one sense mutation, and all are located in areas of conserved synteny. When assessed in terms of haplotypes, these SNPs were significantly associated with variations in cattle fertility and production traits, most notably on calving interval, days to first service and production index (the UK economic index of milk yield measured in £GB).

 

Lei, C. Z., Chen, H., Zhang, H. C., Cai, X., Liu, R. Y., Luo, L. Y., Wang, C. F., Zhang, W., Ge, Q. L., Zhang, R. F., Lan, X. Y., Sun, W. B. 2006. "Origin and phylogeographical structure of Chinese cattle". Animal Genetics, 37 (6): 579-582.

 

KEYWORDS: Chinese cattle, climate, genetic diversity, mitochondrial DNA D-loop origin, phylogeographical structure

 

SUMMARY: Complete mitochondrial D-loop sequences of 231 samples were used to explore the origin and genetic diversity of Chinese cattle. Phylogenetical analysis of these sequences revealed both Bos taurus and Bos indicus mitochondrial types in Chinese cattle. Four of the previously identified mitochondrial DNA lineages (T1–T4) were identified in the Bos taurus type, including lineage T1, which was found for the first time in Chinese cattle. Two lineages (I1 and I2) were identified in the Bos indicus type. Our results support the suggestion that the Yunnan-Guizhou Plateau is the domestication site of Chinese zebu. We also found evidence that Tibetan cattle originated from taurine and zebu cattle. The distribution pattern of Chinese cattle breeds was closely related to the geographical and climatic background. It was possible to divide Chinese cattle in this study into two major groups: northern and southern cattle.

 

Morsci, N. S., Schnabel, R. D., Taylor, J. F. 2006. "Association analysis of adiponectin and somatostatin polymorphisms on BTA1 with growth and carcass traits in Angus cattle". Animal Genetics, 37 (6): 554-562.

 

KEYWORDS: adiponectin, Angus, association, beef, carcass traits, linkage disequilibrium, quantitative trait loci, single nucleotide polymorphism, somatostatin

 

SUMMARY: This study tested positional candidate genes adiponectin (ADIPOQ) and somatostatin (SST) for effects on carcass traits in a commercially relevant cattle population. Both genes are located within a region of BTA1 previously reported to harbour quantitative trait loci (QTL) that affect marbling, quality grade, yield grade, ribeye area and weaning weight in Bos taurus × Bos indicus crosses. Except for the first intron of ADIPOQ, both genes, including over 2 kb upstream of the promoters, were sequenced in five registered Angus sires to identify polymorphisms. A variable copy duplication and three single nucleotide polymorphisms (SNPs) in ADIPOQ and one SNP in SST were genotyped and tested for association with 19 traits in a 14-generation pedigree of 1697 registered Angus artificial insemination sires representing all the major USA lineages of the breed. Linear models that parameterized predicted genetic merits in terms of allele substitution effects were fit by weighted least squares, and goodness-of-fit tests were employed to differentiate causal mutations or polymorphisms in strong linkage disequilibrium (LD) with causal mutations from markers in weak LD with QTL. We confirmed the presence of QTL affecting marbling, ribeye muscle area and fat thickness in the vicinity of SST and ADIPOQ on BTA1 in Angus, excluded SST as underlying the ribeye muscle area QTL, and excluded ADIPOQ as underlying the marbling score QTL. However, association analysis provides very limited information about QTL location and has little intrinsic value when performed in the absence of linkage or LD analysis using flanking marker data to localize the QTL effect relative to positional candidate genes.

 

Shin S. C., E. R. Chung. 2006. "Association of SNP Marker in the Thyroglobulin Gene with Carcass and Meat Quality Traits in Korean Cattle". Asian-Australian Journal of Animal Science 20 (2): 172-177.

 

KEYWORDS: TG Gene, SNP Marker, Marbling Score, Korean Cattle

 

SUMMARY: Thyroid hormones play an important role in regulating metabolism and can affect homeostasis of fat depots. The gene encoding thyroglobulin (TG), producing the precursor for thyroid hormones, has been proposed as a positional and functional candidate gene for a QTL with an effect on fat deposition. The SNP occurs in the 5쨈 promoter region of the TG gene and is widely used in marker assisted selection (MAS) programs to improve the predictability of marbling level and eating quality in beef cattle. In this study, we identified three SNPs at the 5??promoter region of the TG gene in Korean cattle. Of the three SNPs identified in TG gene, the C257T and A335G were previously unreported new SNPs. The sequence data were submitted to GenBank (GenBank accession number: AY615525). The previously reported C422T SNP showed three genotypes, CC, CT and TT, by digestion with the restriction enzyme MflI using the PCR-RFLP method. A new allelic variant corresponding to the C??T and A??G mutations at positions 257 and 335, respectively, could be detected by the SSCP analysis. The gene??specific SNP marker association analysis indicated that the C422T SNP marker was significantly associated (p<0.05) with marbling score. Animals with the CC and CT genotypes had higher marbling score than those with the TT genotype. Results from this study suggest that TG gene-specific SNP may be a useful marker for meat quality traits in future MAS programs in Korean cattle.

 

Zhang R. F., H. Chen, C. Z. Lei, X. T. Fang, Y. D. Zhang, S. R. Hu, L. H. Su 2006. "Association between PCR-RFLP Polymorphisms of Five Gene Loci and Milk Traits in Chinese Holstein". Asian-Australian Journal of Animal Science 20 (2): 166-171.

 

KEYWORDS: Chinese Holstein, beta-lg, kappa-cn, IGFBP-3, Milk Traits

 

SUMAMRY: The objective of this study was to assess the association of polymorphisms in flanking region, CSN1S2, and IGFBP-3 genes with milk production traits and mastitis-related traits in Chinese Holstein. Traits analyzed were 305 day standard milk yield, protein percentage, fat percentage, the ratio of fat percentage and protein percentage, pre-somatic cell count, somatic cell count, and somatic cell score, respectively. CSN1S2 locus was uninformative because only one genotype BB was found in Chinese Holstein. Allele frequencies of A and B in IGFBP-3 gene were 0.5738 and 0.4262 in Chinese Holstein population, which was different from reported Qinchuan cattle population. The genotypes of animals at IGFBP-3 locus significantly affected 305 day standard milk yield, protein percentage, and somatic cell score. The lg genotypes had a significant effect on protein percentage and the ratio of fat percentage and protein percentage. Polymorphism in lg 5flanking region was associated with 305 day standard milk yield, protein percentage, fat percentage, pre-somatic cell count, and somatic cell count. No significant associations of the polymorphism in cn gene were observed for any trait.

 

Bhatti A. A., M. S. Khan, Z. Rehman, A. U. Hyder, F. Hassan. 2006. "Selection of Sahiwal Cattle Bulls on Pedigree and Progeny". Asian-Australian Journal of Animal Science 20 (1): 12-18

 

KEYWORDS: Sahiwal Cattle, Bull Selection, Pedigree, Progeny, Milk Yield

 

SUMMARY: The objective of the study was to compare ranking of Sahiwal bulls selected on the basis of highest lactation milk yield of their dams with their estimated breeding values (EBVs) using an animal model. Data on 23,761 lactation milk yield records of 5,936 cows from five main Livestock Experiment Stations in Punjab province of Pakistan (1964-2004) were used for the study. At present the young A.I bulls are required to be from A-category bull-dams. Dams were categorized as A, B, C and D 2,700, 2,250-2,699, 1,800-2,249 andif they had highest lactation milk yield of <1,800 litres, respectively. The EBVs for lactation milk yield were estimated for all the animals using an individual animal model having fixed effect of herd-year and season of calving and random effect of animal. Fixed effect of parity and random effect of permanent environment were incorporated when multiple lactation were used. There were 396 young bulls used for semen collection and A.I during 1973-2004. However, progeny with lactation yields recorded, were available only for 91 bulls and dams could be traced for only 63 bulls. Overall lactation milk yield averaged 1,440.8 kg. Milk yield was 10% heritable with repeatability of 39%. Ranking bulls on highest lactation milk yield of their dams, the in-vogue criteria of selecting bulls, had a rank correlation of 0.167 (p<0.190) with ranking based on EBVs from animal model analysis. Bulls’ EBVs for all lactations had rank correlation of 0.716 (p<0.001) with EBVs based on first lactation milk yield and 0.766 (p<0.001) with average EBVs of dam and sire (pedigree index). Ranking of bulls on highest lactation yield of their dams has no association with their ranking based on animal model evaluation. Young Sahiwal bulls should be selected on the basis of pedigree index instead of highest lactation yield of dams. This can help improve the genetic potential of the breed accruing to conservation and development efforts.

 

Shin S. C., E. R. Chung. 2006. "Association of SNP Marker in the Leptin Gene with Carcass and Meat Quality Traits in Korean Cattle". Asian-Australian Journal of Animal Science 20 (1):1-6.

 

KEYWORDS: Leptin Gene, SNP Marker, Carcass and Meat Quality Traits, Korean Cattle

 

SUMMARY: Leptin is the hormone product of the obese gene and is synthesized and secreted predominantly by white adipocytes and relates to the feedback system that regulates long-term body fat weight and composition. Therefore, the leptin gene could be an excellent candidate gene controlling fat deposition, carcass traits and meat quality in beef cattle. The objective of this study was to evaluate the association of 3 SNPs (A1127T and C1180T in exon 2 and C3100T in exon 3) in the bovine leptin gene with carcass and meat quality traits in Korean cattle. The C1180T SNP was associated with backfat thickness (BF) and marbling score (MS) (p<0.05). Animals with the genotype CC had higher BF than animals with TT genotype and higher MS compared with CT and TT genotypes. No significant associations were observed between the C3100T SNP and any carcass and meat quality traits analyzed. The effect of the A1127T SNP was not analyzed because the TT genotype was not detected and the AT genotype showed only 1.0% frequency. These results suggest that the C1180T SNP of the leptin gene may be useful as a genetic marker for carcass and meat quality traits in Korean cattle.

 

Clawson Michael L, Michael P Heaton, John W Keele, Timothy PL Smith, Gregory P Harhay, William W Laegreid. 2006. "Prion gene haplotypes of U.S. cattle". BMC Genetics 2006, 7:51

 

KEYWORDS: Prion gene, haplotypes, cattle

 

SUMMARY: Bovine spongiform encephalopathy (BSE) is a fatal neurological disorder characterized by abnormal deposits of a protease-resistant isoform of the prion protein. Characterizing linkage disequilibrium (LD) and haplotype networks within the bovine prion gene (PRNP) is important for 1) testing rare or common PRNP variation for an association with BSE and 2) interpreting any association of PRNP alleles with BSE susceptibility. The objective of this study was to identify polymorphisms and haplotypes within PRNP from the promoter region through the 3'UTR in a diverse sample of U.S. cattle genomes. A 25.2-kb genomic region containing PRNP was sequenced from 192 diverse U.S. beef and dairy cattle. Sequence analyses identified 388 total polymorphisms, of which 287 have not previously been reported. The polymorphism alleles define PRNP by regions of high and low LD. High LD is present between alleles in the promoter region through exon 2 (6.7 kb). PRNP alleles within the majority of intron 2, the entire coding sequence and the untranslated region of exon 3 are in low LD (18.0 kb). Two haplotype networks, one representing the region of high LD and the other the region of low LD yielded nineteen different combinations that represent haplotypes spanning PRNP. The haplotype combinations are tagged by 19 polymorphisms (htSNPS) which characterize variation within and across PRNP. The number of polymorphisms in the prion gene region of U.S. cattle is nearly four times greater than previously described. These polymorphisms define PRNP haplotypes that may influence BSE susceptibility in cattle.

 

Garnero, Analía Del Valle, Marcondes, Cintia Righetti, Gunski, Ricardo José. 2006. "Genetic trends in the expected progeny difference of the asymptotic weight of Nelore females". Genetics and Molecular Biology, 29 (4): 648-652.

 

KEYWORDS: adult weight, bovine(s), genetic trends, maturation rate, simulation with growth curves.

 

SUMMARY: There are few studies on weight covering the full life cycle of Zebu cattle, and there is no entire growth description or mean growth pattern for animals belonging to this breed. In order to provide such data, 1,158 Nelore females born between 1985 and 1995 were weighed 14,563 times from birth to full growth maturity, in ten herds spread over seven Brazilian states. The Von Bertalanffy, Brody, logistic and Gompertz non-linear models were used to obtain the asymptotic weights (A) and the maturation rates (K). The (co)variance and breeding value components for A and K were obtained by using the multiple trait derivative free restricted maximum likelihood method under the animal model. Genetic trends were calculated in function of the mean expected progeny differences (EPD) for the trait (A or K) divided by the number of animals according to their year of birth. The genetic trends of the expected progeny difference with reference to the date of birth of the cows were, on average, -6.5g y-1 for A and 2.0g y-1 for K, close to zero as confirmed by the low (0.0023 to 0.003) coefficient of regression values. The curve parameters are recommended as a selection criterion to reach precocity and avoid adult weight increase in the female herd.

 

Nascimento, Carlos Souza Do, Machado, Marco Antonio, Martinez, Mario Luiz. 2006. "Association of the bovine major histocompatibility complex (BoLA) BoLA-DRB3 gene with fat and protein production and somatic cell score in Brazilian Gyr dairy cattle (Bos indicus)". Genetics and Molecular Biology, 29 (4): 641-647.

 

KEYWORDS: cattle, marker-assisted selection, molecular markers, PCR-RFLP.

 

SUMMARY: The effect of the bovine major histocompatibility complex (BoLA) locus on animal health may be due to a direct action of its alleles on immune functions, whereas its indirect effect on production traits might be explained by the better general health conditions of more productive animals. In the present study, the BoLA-DRB3 gene was investigated in 1058 cows belonging to seven Brazilian Gyr Dairy herds (Bos indicus, Zebu cattle). A total of 37 alleles were identified, 15 of them described for the first time in a Zebu breed. A highly significant association (p < 0.02) was observed between allele *54 and a decrease (-26.1 kg) in milk protein yield and there was a significant association (p < 0.05) between this allele and lower (-26.07 kg) milk fat yield. There was also a significant association (p < 0.05) between allele *6 and decreased (-12.47 kg) milk protein and allele *7 and increased (12.72 kg) milk protein. There were also indications of association (p < 0.10) between somatic cell score (SCS) and alleles *3 (SCS increased by 0.54 units) and *31 (SCS increased by 0.46 units). The highly significant association of allele *54 with lower protein yield suggests the possible use of this allele in marker-assisted selection programs.

 

Ohkubo, T., Yano, H., Takahashi, S., Takahashi, K., Kimura, N., Tanaka, M. 2006. "Bos indicus type of growth hormone receptor gene is retained in Japanese Black cattle". Journal of Animal Breeding and Genetics, 123 (6): 410-413.

 

KEYWORDS: growth hormone receptor, Japanese Black cattle, polymorphism, promoter

 

SUMMARY: The growth hormone receptor (GHR) gene is responsible for growth and carcass traits, and polymorphisms associated with the variation of meat production are thought to occur in the liver-specific promoter of the GHR gene in cattle. The aim of this study was to analyse the structure of the liver-specific promoter of GHR in Japanese Black cattle, as the relationship between GHR polymorphism and meat production is poorly understood in this breed. Typically in European cattle, the LINE-1 element, a family of retrotransposons, is inserted in the liver-specific promoter. However, a short GHR promoter without the LINE-1 sequence was found in the Japanese Black breed as in Bos indicus cattle. The frequency of the short allele was approximately 60%. In addition, 24 of 29 Holstein/Japanese Black crosses carried the short allele from their sire. The present result suggests that the short allele for GHR may be a candidate marker for improving meat production of Japanese Black cattle.

 

Calus M. P. L., L. L. G. Janss, R. F. Veerkamp. 2006. "Genotype by Environment Interaction for Somatic Cell Score Across Bulk Milk Somatic Cell Count and Days in Milk" Journal of Dairy Science, 89:4846-4857

 

KEYWORDS: somatic cell count, genotype x environment interaction, reaction norm model, test-day model

 

SUMMARY: The objective of this paper was to investigate the importance of a genotype x environment interaction (G x E) for somatic cell score (SCS) across levels of bulk milk somatic cell count (BMSCC), number of days in milk (DIM), and their interaction. Variance components were estimated with a model including random regressions for each sire on herd test-day BMSCC, DIM, and the interaction of BMSCC and DIM. The analyzed data set contained 344,029 test-day records of 24,125 cows, sired by 182 bulls, in 461 herds comprising 13,563 herd test-days. In early lactation, considerable G x E effects were detected for SCS, indicated by 3-fold higher genetic variance for SCS at high BMSCC compared with SCS at low BMSCC, and a genetic correlation of 0.72 between SCS at low and at high BMSCC. Estimated G x E effects were smaller during late lactation. Genetic correlations between SCS at the same level of BMSCC, across DIM, were between 0.43 and 0.89. The lowest genetic correlation between SCS measures on any 2 possible combinations of BMSCC and DIM was 0.42. Correlated responses in SCS across BMSCC and DIM were, on some occasions, less than half the direct response to selection in the response environment. Responses to selection were reasonably high among environments in the second half of the lactation, whereas responses to selection between environments early and late in lactation tended to be low. Selection for reduced SCS yielded the highest direct response early in lactation at high BMSCC.

 

Soyeurt H., P. Dardenne, A. Gillon, C. Croquet, S. Vanderick, P. Mayeres, C. Bertozzi, N. Gengler. 2006. "Variation in Fatty Acid Contents of Milk and Milk Fat Within and Across Breeds". Journal of Dairy Science, 89: 4858-4865

 

KEYWORDS: milk quality, breed difference, fatty acid, fat

 

SUMMARY: The aim of this research was to study the potential for selection of cows with a higher nutritional quality of milk fat by studying the differences in fatty acid profiles within and across the following breeds: Dual Purpose Belgian Blue, Holstein-Friesian, Jersey, Montbeliarde, and non-Holstein Meuse-Rhine-Yssel type Red and White. Six hundred milk samples from 275 animals were taken from 7 herds. Several types of fatty acids in milk and milk fat were quantified using mid-infrared spectrometry and previously obtained calibration equations. Statistical analyses were made using a mixed linear model with a random animal effect. The variance components were estimated by using REML. Results showed breed differences for the fatty acid profile. The repeatability estimate obtained in the present study may suggest the existence of moderate additive genetic variance for the fatty acid profile within each breed. Results also indicated variation for each analyzed milk component in the whole cow population studied. Genetic improvement of the nutritional quality of milk fat based on fatty acid profiles might be possible, and further research and development are warranted.

 

Togashi K., C. Y. Lin. 2006. "Selection for Milk Production and Persistency Using Eigenvectors of the Random Regression Coefficient Matrix". Journal of Dairy Science, 89: 4866-4873

 

KEYWORDS: lactation curve, lactation milk, persistency, eigenvector index

 

SUMMARY: The purpose of this study was to investigate the relationships of the eigenvectors of the additive genetic random regression coefficient matrix (K) to selection responses and to determine how many eigenvectors are necessary in the breeding goal to explain the variation. The construction of various eigenvector indexes was based on the K matrix estimated from test-day records of Japanese Holstein cattle. The first (leading) eigenvector index produced constant responses for each day of lactation, indicating that the first eigenvector is responsible for scaling the lactation curve without altering its shape. Daily genetic responses to the second eigenvector index increased linearly as DIM increased. Genetic responses to the third eigenvector index were negative in mid-lactation but were positive in early and late lactation (concave curve). Genetic responses to the fourth and fifth eigenvector indexes hovered around zero across the lactation. The results suggest that both second and third eigenvectors account for the change in the shape of the lactation curve and there is little utility of the fourth and fifth eigenvectors in improving lactation milk or persistency. When the goal is to increase lactation milk yield alone, the index based on the first eigenvector produced a similar response to the index based on all 5 eigenvectors. When the goal is to improve both lactation milk yield and persistency, the index based on the first 3 eigenvectors achieved more than 99.9% of the genetic response to an index based on all 5 eigenvectors. The advantage of an eigenvector index over conventional selection based on total lactation milk yield increases with increasing economic weight assigned to persistency.

 

Mark T., P. G. Sullivan. 2006. "Multiple-Trait Multiple-Country Genetic Evaluations for Udder Health Traits". Journal of Dairy Science, 89: 4874-4885

 

KEYWORDS: multiple trait, international genetic evaluation, clinical mastitis, somatic cell concentration

 

SUMMARY: International genetic bull evaluations of somatic cell counts (SCC) from 8 different Holstein populations and clinical mastitis from 3 of these populations were inferred simultaneously using a multiple-trait–multiple-country evaluation (MT-MACE) model. This model considered effective independent weighting factors and multivariately deregressed national genetic evaluations for countries with multiple-trait national models. Predictions of genetic merit from MT-MACE and their reliabilities were compared with the corresponding results from 2 separate single-trait–multiple-country evaluations (ST-MACE) for different groups of bulls. The assumed heritabilities for clinical mastitis (h2 = 0.02 to 0.05) were substantially lower than the heritabilities for SCC (h2 = 0.08 to 0.27). The predictive ability of MT-MACE was essentially equal to or better than the predictive ability of ST-MACE for all country-trait combinations, but both methods yielded effectively unbiased and consistent consecutive predictions (correlation > 0.93). Both sets of predictions also agreed well with future national genetic evaluations for bulls receiving additional daughter information (correlation > 0.96), except for evaluations for which within-country correlations were utilized internationally, but not nationally (correlation = 0.86 to 0.97). The reliabilities for MT-MACE were essentially equal to or higher than reliabilities for ST-MACE, depending on the trait and group of bulls in question. Reliabilities increased most for young bulls, and for clinical mastitis in countries that did not use the within-country correlations with SCC in the national evaluation (up to a 23% increase in average reliability). (Feb. 2007)

 

Miglior F., A. Sewalem, J. Jamrozik, D. M. Lefebvre, R. K. Moore. 2006. "Analysis of Milk Urea Nitrogen and Lactose and Their Effect on Longevity in Canadian Dairy Cattle". Journal of Dairy Science, 89: 4886-4894

 

KEYWORDS: milk urea nitrogen, lactose, longevity

 

SUMMARY: The aim of this study was to assess the phenotypic level of lactose and milk urea nitrogen concentration (MUN) and the association of these traits with functional survival of Canadian dairy cattle using a Weibull proportional hazards model. A total of 1,568,952 test-day records from 283,958 multiparous Holstein cows from 4,758 herds, and 79,036 test-day records from 26,784 multiparous Ayrshire cows from 384 herds, calving from 2001 to 2004, were used for the phenotypic analysis. The overall average lactose percentage and MUN for Ayrshires were 4.49% and 12.20 mg/dL, respectively. The corresponding figures for Holsteins were 4.58% and 11.11 mg/dL. Concentration of MUN increased with parity number, whereas lactose percentage decreased in later parities. Data for survival analysis consisted of 39,536 first-lactation cows from 1,619 herds from 2,755 sires for Holsteins and 2,093 cows in 228 herds from 157 sires for Ayrshires. Test-day lactose percentage and MUN were averaged within first lactation. Average lactose percentage and MUN were grouped into 5 classes (low, medium-low, medium, medium-high, and high) based on mean and standard deviation values. The statistical model included the effects of stage of lactation, season of production, the annual change in herd size, type of milk-recording supervision, age at first calving, effects of milk, fat, and protein yields calculated as within herd-year-parity deviations, herd-year-season of calving, lactose percentage and MUN classes, and sire. The relative culling rate was calculated for animals in each class after accounting for the remaining effects included in the model. Results showed that there was a statistically significant association between lactose percentage and MUN in first lactation with functional survival in both breeds. Ayrshire cows with high and low concentration of MUN tended to be culled at a higher than average rate. Instead, Holstein cows had a linear association, with decreasing relative risk of culling with increasing levels of MUN concentration. The relationship between lactose percentage and survival was similar across breeds, with higher risk of culling at low level of lactose, and lower risk of culling at high level of lactose percentage.

 

Wiggans G. R., L. L. M. Thornton, R. R. Neitzel, N. Gengler. 2006. "Genetic Parameters and Evaluation of Rear Legs (Rear View) for Brown Swiss and Guernseys". Journal of Dairy Science, 89: 4895-4900

 

KEYWORDS: rear legs, type trait, genetic evaluation

 

SUMMARY: Genetic parameters were estimated for rear legs (rear view, RLRV) and 15 current linear type traits of Brown Swiss and Guernsey dairy cattle. The Brown Swiss Cattle Breeders’ Association of the USA and the American Guernsey Association began scoring RLRV in 2004. For Brown Swiss, 8,502 records were available for 7,676 cows in 417 herds, Guernsey data included 5,437 records for 4,749 cows in 229 herds. Nine unknown-parent groups were defined for each breed, each with 2 birth years. The model included fixed effects for the interaction of herd, appraisal date, and parity, appraisal age within parity, and lactation stage within parity and random effects for animal, permanent environment, and residual error. The multitrait analysis for RLRV and the 15 linear type traits used canonical transformation, multiple diagonalization, and a decelerated expectation–maximization REML algorithm. For Brown Swiss, heritability was 0.102 for RLRV and ranged from 0.099 for rear legs (side view) to 0.453 for stature. For Guernseys, heritability ranged from 0.078 for RLRV to 0.428 for stature. For Brown Swiss, the highest genetic correlation with RLRV was 0.71 for rear udder width, the most negative correlation was –0.19 with rump angle. For Guernseys, the highest genetic correlations with RLRV were 0.43 for rear udder width and 0.42 for body depth, the most negative correlation was –0.46 with rear legs (side view). With heritability near 0.10, RLRV should be useful in selection for improved locomotion. Release of genetic evaluations for RLRV began in May 2006 for Brown Swiss and Guernseys.

 

Woolliams J. A.. 2006. "Technical Note: A Note on the Differential Impact of Wrong and Missing Sire Information on Reliability and Gain". Journal of Dairy Science, 89: 4901-4902

 

KEYWORDS: reliability, gain, wrong sire information, missing sire information

 

SUMMARY: This note analytically derives the impact that wrong and missing sire information (WSI and MSI, respectively) has on the reliability of predicting merit and gain compared with perfect information. In particular, for small WSI and MSI, WSI was shown to have twice the impact of MSI for both reliability and gain, and the impact of both WSI and MSI increased as the reliability of predicting merit with perfect information decreased. The overall impact on the efficiency of gain for small WSI and MSI was half the overall impact on reliability.

 

Schneider M. del P., E. Strandberg, V. Ducrocq, A. Roth. 2006. "Short Communication: Genetic Evaluation of the Interval from First to Last Insemination with Survival Analysis and Linear Models". Journal of Dairy Science, 89: 4903-4906

KEYWORDS: female fertility, genetic evaluation, survival analysis

SUMMARY: Sire breeding values for the interval between the first and last insemination were predicted using 4 proportional hazards models (survival analyses) and 2 linear mixed models to determine which would result in a more accurate genetic evaluation. A stochastic simulation describing the reproductive cycle of first-parity cows was conducted, in which true breeding values for conception rate were created. The model included the effects of sire and herd. The highest correlations between true breeding values for conception rate and breeding values for the interval between first and last insemination predicted by the survival analysis model and the linear model were 0.803 and 0.744, respectively. The results showed that when pregnancy status was known, survival models were more accurate than linear models to predict breeding values for conception rate when using observations on the interval between first and last insemination.

 

Kuhn M. T., J. L. Hutchison, G. R. Wiggans. 2006. "Characterization of Holstein Heifer Fertility in the United States". Journal of Dairy Science, 89: 4907-4920

 

KEYWORDS: heifer fertility, conception rate, genetic correlation, threshold model

 

SUMMARY: The overall object of this research was to characterize US Holstein (virgin) heifer fertility. This included investigation of factors influencing heifer fertility and estimation of heritability, as well as correlations with cow fertility and first-lactation milk yield. A secondary objective was to compare linear and logistic model estimates of fixed effects and linear and threshold model estimates of heritability. Data consisted of Holstein heifers, which were artificially inseminated, with their first breeding between March 2003 and August 2005. Herds were required to have at least 60 breedings across the 3 yr of data and an overall mean conception rate (CR) between 20 and 80%. After edits there were 537,938 breedings of 362,512 heifers in 2,668 herds from 41 states used for analysis. After edits, the overall mean CR for US Holstein heifers was 57%. Linear and logistic model estimates for all factors were nearly identical. Year of breeding accounted for the most variation in heifer CR, with heifer age and month of breeding being the next most important factors. Conception rate in heifers is maximal at an intermediate age of 15 to 16 mo. Heifers at 26 mo of age and older have roughly a 10% lower CR than heifers bred at younger ages. Although month of breeding affected heifer CR, effects are less than for cows. In contrast to cow fertility, heifer CR is nearly as good in the hotter summer months as in cooler months. Approximately 88% of US herds had a 40 to 70% heifer CR. Heritability estimates of heifer CR on first service were 0.5% from the linear model and 1.0% from the threshold model. Genetic correlation estimates of heifer CR on first service with cow CR on first service and with first-lactation milk yield were 0.39 and –0.19, respectively. Results indicated that selection on either the currently available US daughter pregnancy rate evaluations for cow fertility or on cow CR will also improve heifer fertility. Furthermore, heritability of heifer CR is lower than for cow CR and reporting of heifer breedings is currently less complete than for cow breedings. Thus, there are currently no immediate plans to implement a US genetic evaluation for heifer CR.

 

Ron M., M. Cohen-Zinder, C. Peter, J. I. Weller, G. Erhardt. 2006. "Short Communication: A Polymorphism in ABCG2 in Bos indicus and Bos taurus Cattle Breeds". Journal of Dairy Science, 89: 4921-4923

 

KEYWORDS: ATP binding cassette G2 gene, Bos taurus chromosome 6, single nucleotide polymorphism

 

SUMMARY: A single nucleotide change (A/C) in exon 14 is capable of encoding a substitution of tyrosine-581 to serine (Y581S) in the ABCG2 (ATP binding cassette, subfamily G, member 2) gene and affects milk production traits. The ABCG2A allele decreases milk yield and increases protein and fat concentration. The allele frequencies were determined in 32 Bos taurus and 3 Bos indicus breeds, ABCG2A was predominant in all populations. This allele approached fixation in 23 out of 35 breeds, including all 3 Bos indicus breeds. The ABCG2C allele was found in the Belgian Blue (beef), Belgian Blue Mix, British Friesian, Bohemian Red, East Anatolian Red, German Angus, German Black Pied, German Brown, German Simmental, Israeli Holstein, Menorquina, and US Holstein breeds. Thus, the genetic gain expected from selection for ABCG2A may be limited. The detection of ABCG2C only in Bos taurus breeds may indicate that ABCG2A is the ancestral allele, and that the Y581S substitution occurred after the separation of the Bos indicus and Bos taurus lineages.

 

Casas E., R. T. Stone. 2006. "Putative quantitative trait loci associated with the probability of contracting infectious bovine keratoconjunctivitis". Journal of Animal Science, 84:3180-3184

 

KEYWORDS: bovine keratoconjunctivitis, quantitative trait locus

 

SUMMARY: Infectious bovine keratoconjunctivitis, also known as pinkeye, is an economically important disease in cattle. The objective of this study was to detect QTL associated with infectious bovine keratoconjunctivitis in offspring from a Brahman x Hereford sire. The sire was mated to Hereford, Angus, and F1 cows to produce 288 offspring in 1994 and mated to MARC III ( Hereford, Angus, Red Poll, and Pinzgauer) cows in 1996 to produce 259 offspring (547 animals total). Infectious bovine keratoconjunctivitis was diagnosed by physical examination in 36 animals of the family. Records included unilateral and bilateral frequency, but not severity. Records were binary: 0 for unaffected and 1 for affected cattle. A putative QTL for infectious bovine keratoconjunctivitis was identified on chromosome 1, with a maximum F-statistic (F = 10.15, P = 0.0015) at centimorgan 79 of the linkage group. The support interval spanned centimorgans 66 to 110. There was also evidence suggesting the presence of a QTL for infectious bovine keratoconjunctivitis on chromosome 20, with a maximum F-statistic (F = 10.35, P = 0.0014) at centimorgan 16 of the linkage group. The support interval ranged from centimorgan 2 to 35. This report provides the initial evidence of QTL for infectious bovine keratoconjunctivitis. Although a candidate gene was identified for one of the regions of interest, further studies are needed to identify the genetic basis of resistance to the disease.

 

Guerra J. L. L., D. E. Franke, D. C. Blouin. 2006. "Genetic parameters for calving rate and calf survival from linear, threshold, and logistic models in a multibreed beef cattle population". Journal of Animal Science, 84: 3197-3203.

 

KEYWORDS: beef cattle, genetic parameter, reproductive trait, statistical method

 

SUMMARY: Generalized mixed linear, threshold, and logistic sire models and Markov chain, Monte Carlo simulation procedures were used to estimate genetic parameters for calving rate and calf survival in a multibreed beef cattle population. Data were obtained from a 5-generation rotational crossbreeding study involving Angus, Brahman, Charolais, and Hereford (1969 to 1995). Gelbvieh and Simmental bulls sired terminal-cross calves from a sample of generation 5 cows. A total of 1,458 cows sired by 158 bulls had a mean calving rate of 78% based on 4,808 calving records. Ninety-one percent of 5,015 calves sired by 260 bulls survived to weaning. Mean heritability estimates and standard deviations for daughter calving rate from posterior distributions were 0.063 ± 0.024, 0.150 ± 0.049, and 0.130 ± 0.047 for linear, threshold, and logistic models, respectively. For calf survival, mean heritability estimates and standard deviations from posterior distributions were 0.049 ± 0.022, 0.160 ± 0.058, and 0.190 ± 0.078 from linear, threshold, and logistic models, respectively. When transformed to an underlying normal scale, linear sire, mixed model, heritability estimates were similar to threshold and logistic sire mixed model estimates. Posterior density distributions of estimated heritabilities from all models were normal. Spearman rank correlations between sire EPD across statistical models were greater than 0.97 for daughter calving rate and for calf survival. Sire EPD had similar ranges across statistical models for daughter calving rate and for calf survival.

 

Ibi T., A. K. Kahi, H. Hirooka. 2006. "Effect of carcass price fluctuations on genetic and economic evaluation of carcass traits in Japanese Black cattle". Journal of Animal Science, 84:3204-3211.

 

KEYWORDS: bovine spongiform encephalopathy, carcass price, economic weight, genetic parameter

 

SUMMARY: The objectives of this study were 1) to investigate the effect of changes in carcass market prices due to bovine spongiform encephalopathy (BSE) occurrences on estimates of genetic parameters and economic weights for carcass traits, and 2) to compare direct and indirect approaches for prediction of genetic merit of Japanese Black cattle for profitability of their progeny. The direct approach utilized estimated breeding values of carcass prices, whereas in the indirect approach, selection indices were constructed as products of economic weights and breeding values of component traits. Data were composed of 80,191 carcass records divided into 5 periods based on changes in carcass prices as a result of occurrences of BSE in Japan and the United States. The periods ranged from a period before occurrence of BSE in Japan to a period of beef import restrictions and a rise in prices. Carcass traits analyzed included HCW, LM area, rib thickness, subcutaneous fat thickness, and marbling score (MS). Price traits included carcass unit price and carcass sale price. Estimates of heritability for price traits were moderate (0.32 to 0.46) and slightly sensitive to changes in carcass market prices. Genetic correlations of HCW and LM area with price traits increased and that between MS and carcass sale price decreased with period, whereas estimates of genetic correlation between MS and carcass unit price were high in all periods (0.96 to 0.98). Economic weights for carcass traits varied with periods because carcass prices were highly sensitive to economic importance of traits. Nevertheless, correlations between within-period breeding values for price traits estimated using direct and indirect approaches were high (0.92 to 0.99). This result indicates that selection realized by direct and indirect approaches will provide very similar results. A comparison among within-approach breeding values estimated in different periods showed that the largest differences in breeding values of sires for price traits were between the periods after occurrences of BSE in Japan and in the United States. Economic effects of BSE occurrences influenced the importance of carcass traits and economic merits of price traits through a change of carcass prices from period to period, irrespective of the approach taken in determining the genetic merit of breeding animals for profitability of their progeny.

 

Van Groningen C., C. J. B. Devitt, J. W. Wilton, J. A. L. Cranfield. 2006. "Economic evaluations of beef bulls in an integrated supply chain". Journal of Animal Science, 84: 3219-3227.

 

KEYWORDS: beef production, bioeconomic model, genetic evaluation, sire ranking

 

SUMMARY: Economic benefits from the use of expected progeny of a sample of beef bulls with genetic evaluations were calculated over an integrated supply chain for combinations of price discounts for intramuscular fat and LM area. Fixed backfat finish and marketing at the point of optimized gross margins were considered. An economic model was used to calculate average expected gross margins for a sample of bulls. Across-breed, age-constant genetic evaluations were used to predict carcass characteristics of progeny including weight, retail yield, intramuscular fat, and LM area, as well as input requirements including feed and housing as a function of time on feed. Proportion of retail cuts affected by price discounts was included in the calculations. Optimizing endpoints did not affect rankings to any extent relative to a fixed end point in this sample of bulls, as a result of fixed endpoints being similar to optimized endpoints for the economic situation considered. However, rank correlations were only 0.63 and 0.71 between rankings for no discount being applied and rankings with discounts for intramuscular fat and LM area, for fixed and optimized endpoints, respectively. We conclude that market prices are necessary considerations in choices of bulls to use in commercial beef production.

 

eixeira, Rodrigo De Almeida, Albuquerque, Lucia Galvão De, Alencar, Maurício Mello De. 2006. "Genotype by environment interaction on crossbreed beef cattle". Revista Brasileira de Zootecnia, 35 (4, suppl): 1677-1683.

 

KEYWORDS: genetic group, heterosis, yearling, weaning.

 

SUMMARY: Data from Hereford and Nelore breeds and their crosses were used to estimate the effect of genotype and environment interaction on weaning and yearling weights. The statistical analyses were performed by the least-squares method using models that included region, contemporary group within region, month of birth and sex of the calf, linear and quadratic effects of age of the calf and age of the cow, both nested within sex, and the genetic group and genetic group × region interaction effects. In general, genetic groups were influenced by the region effect. Differences in performance between regions decreased as the proportional contribution of zebu increased. All genotypes increased performance in the less restrictive environment. Crossbreeding systems should consider keeping fitness of dams and their products to environmental conditions.

 

Pereira, Márcio Cinachi, Mercadante, Maria Eugênia Zerlotti, Albuquerque, Lucia Galvão De . 2006. "Estimates of genetic parameters for growth traits of Caracu cattle selected for yearling weight". Revista Brasileira de Zootecnia, 35 (4, suppl.): 1669-1676.

 

KEYWORDS: beef cattle, genetic correlation, heritability.

 

SUMMARY: Records of growth traits of 1,698 animals born from 1979 to 2002 in a Caracu herd selected for yearling weight were used to estimate genetic parameters for birth weight (PN), weight at 4 months adjusted at 120 days (P120), weaning weight adjusted at 210 days (P210), daily weight gain from birth to weaning (GND), weight adjusted at 378 days of males (P378), weight adjusted at 550 days of heifers (P550), daily weight gain during the performance test (G112), post-weaning daily weight gain of males (GDSm), post-weaning daily weight gain of heifers (GDSf), hip height of males (ALTm) and hip height of heifers (ALTf). Components of covariance were estimated by multiple trait derivative free maximum likelihood, using the software MTDFREML. Heritability and standard errors for PN, P120, P210, GND, P378, P550, GDSm, GDSf, G112, ALTm and ALTf were respectively 0.34±0.06, 0.11±0.05, 0.13±0.05, 0.11±0.05, 0.35±0.09, 0.42±0.09, 0.31±0.09, 0.13±0.06, 0.21±0.08, 0.55±0.11 and 0.51±0.09. Except for some estimates for GDSf and PN, genetic correlations between traits were moderate to high and the positive. Genetic gains on growth traits are expected by direct selection on individual performance.

 

Dionello, Nelson José Laurino, Silva, Carlos Alberto Soares Da, Costa, Claudio Napolis. 2006. "Estimation of genetic parameters for test day milk yield of first lactation Jersey cows using repeatability and random regression models". Revista Brasileira de Zootecnia, 35 (4, suppl.): 1646-1652.

 

KEYWORDS: dairy cattle, genetic evaluation, heritability, random regression, repeatability, selection, variance components.

 

SUMMARY: Data consisting of 3,531 test day records of 620 first parity Jersey cows were used to estimate genetic parameters for milk yield. Covariance components were estimated by repeatability and random regression animal models. The Wilmink function was used in the random regression model to fit the fixed effect of season of calving and the additive genetic, permanent environment and residual random effects. The repeatability model included the fixed effects of herd-year-month of test, season of calving and age at calving as a covariable with linear and quadratic terms and animal, permanent environmental and residual random effects. The estimates of additive genetic, permanent environmental, residual and phenotypic variances, heritability and repeatability obtained by the repeatability model for milk yield were, respectively: 7.08, 1.88, 7.79 and 16.76 kg2, 0.42 and 0.50. The estimates of heritability for milk yield obtained from the random regression model decreased from 0.81 in the beginning of the lactation to 0.20 in the end. Larger estimates of genetic variance were observed at the extremes of the lactation period, but they were practically constant in mid-lactation. The permanent environmental variances increased along lactation. Genetic correlations between milk yields were larger in close test days, particularly in mid-lactation and decreased for the most distant test days. Genetic parameters do not indicate the repeatability model as an alternative to use test day records in order to estimate breeding values for milk yield of Jersey cows in Brazil.

 

Aguiar, Gyselle Viana, Araujo, Airton Alencar and Moura, Arlindo De Alencar Araripe. 2006. "Testicular development, spermatogenesis and hormonal concentrations in Angus bulls". Revista Brasileira de Zootecnia, 35 (4, suppl): 1629-1638.

 

KEYWORDS: estradiol, Sertoli, testis, testosterone.

 

SUMMARY: This study aimed to evaluate changes in hormone secretion and in seminiferous epithelium of Angus bulls between 10 and 38 weeks of age. Samples of testicular parenchyma and blood were collected from 25 animals castrated in 4 week intervals. Traits associated to testicular development and quantitative aspects of spermatogenesis and hormonal concentrations were transformed by logarithm before analyses of variance. Changes in testis and seminiferous tubule diameter and testis weight were more pronounced after 26 weeks of age. The percentage of testicular parenchyma occupied by seminiferous tubules increased from 49.3 to 75.2% from 10 to 38 weeks. Most tubules (>90%) had only Sertoli cells at 10 and 14 weeks, but the number of tubules with gonocytes and A spermatogonia increased at 18 (13.8±1.7%) and 22 weeks (19±1%). Tubules with B and intermediate spermatogonia became predominant at 26 weeks (24.5±8.2%) and those with spermatocytes as the most advanced germ cell type were more evident at 30 weeks (42.3±9.9%). Round spermatids were detected at 26 weeks and at 38 weeks of age, 62.3±1.5% of all tubules had either elongate or mature spermatids. Variations in testis growth (specially testis weight) after 26 weeks were coincident with the establishment of meiosis in the seminiferous tubules, morphological alterations in nucleus and nucleolus of the Sertoli cells (indicators of Sertoli cell differentiation), lower levels of androstenedione and significant increases in testosterone and estradiol 17. Associations between testis development and concentrations of FSH and LH were less evident.

 

Samarütel Jaak, Katri Ling, Hanno Jaakson, Tanel Kaart, Olav Kärt. 2006. "Effect of body condition score at parturition on the production performance, fertility and culling in primiparous estonian holstein cows". Veterinarija Ir Zootechnika. T. 36 (58).

 

KEYWORDS: body condition score, milk yield, fertility, primiparous Estonian Holstein cows

 

SUMMARY: The objective of this study was to estimate the relation of body condition score (BCS) near calving to the body condition change in early lactation, the reproductive performance, milk yield and culling rate in the first lactation Estonian Holstein dairy cows. Cows were divided into three groups based on their BCS at calving, thin, BCS ≤3.0 (n=29), moderate, BCS 3.25–3.5 (n= 48), and fat, BCS ≥3.75 (n=27). During the first and second month of lactation the fat cow group had significantly higher (P<0.05) fat corrected milk (FCM) production, milk fat percentage, and milk fat to protein ratio compared to thin cows. Thin cow group had significantly (P<0.05) higher genetic merit index (GMI) compared to the moderate and fat group, but they could not realise their genetic potential as the 305-day fat corrected milk production, fat production, and milk fat + protein production was significantly higher (P<0.01) in fat cows compared to thin cow group. No cows in the fat group conceived from the first service. In the thin group 14%, in the moderate group 25% and in the fat group 41% cows were culled during the first lactation respectively. We concluded that while taking into account besides milk production the aspects of health and fertility, the reasonable BCS at calving of first lactation Estonian Holstein cows in the present management and feeding conditions was 3.25–3.5 BC units.

 

Česlovas Jukna, Vigilijus Jukna, Nijolė Pečiulaitienė. 2006. "The influence of Lithuanian black & white breed bulls on offsprings fatten and meat traits". Veterinarija Ir Zootechnika. T. 36 (58).

 

KEYWORDS: Lithuanian Black & White, bulls, growth speed, carcass yield, meat quality.

 

SUMMARY: The influence of different Lithuanian Black & White bulls on the offsprings fatten and meat traits was investigated. It was established that offsprings of bulls Bangas LBW 4473 had on 7.6 cm cornerwise longer trunk (p<0.01), on 6.4 cm bigger of rear half size and on 2.8 cm longer spiral measure of ham compared to the offsprings of bull Rekas LBW 4197. Furthermore, offsprings of bull Rimbas LBW 4447 had on 12.3 cm (p<0.001) bigger pectoral size compared to the offsprings of bull Rekas LBW 4197. Offsprings of bull Rimbas LBW 4447 used least 68.9 MJ AE for unit of makeweight kg from 120 to 500 days of age. However, carcass yield % of all offsprings of considered bulls was comparable and yield of the ham % offsprings of bulls Bangas LBW 4473 was on 3.9 % (p<0.01) superior compared to the offsprings of bulls Rimbas LBW 4447. In addition, meat off offsprings of bull Bangas LBW 4473 had on 2.5 % (p<0.001) higher content of dry material compared to the meat of offsprings of bull Rekas LBW 4197. Further, the offsprings of Rekas LBW 4197 had significantly higher (P<0.05) water binding capacity and cooking loss compared to offsprings of Bangas LBW 4473. Hard meat (2.41 kg/cm2) was established in offsprings of Rimbas LBW 4447 and soft meat (1.38 kg/cm2 ) in the offsprings of Rekas LBW 4197. Higher amount of fat was concentrated in offsprings of Bangas LBW 4473 compared to the offsprings of Rekas LBW 4197. This study proved our hypothesis, that Lithuanian White & Black breed bulls have marked influence on offsprings fatten and meat traits.

 

Gaworski Marek. 2006. "Analysis of different forms of advance in dairy production". Veterinarija Ir Zootechnika. T. 35 (57).

 

KEYWORDS: automatic milking system, dairy, quality, milking capacity.

 

SUMMARY: Dynamic transformation of dairy production in regional and global scale emphasizes many problems and raise many questions. When we assess results of dairy cows improvement expressed by increase with milking capacity per cow, there can be raised research problem: is this improvement associated with development of other factors deciding about effectiveness of dairy production? What are the possible consequences coming from difference in rate of introduced biological, technological and technical advance in dairy farm? To answer for such formulated questions constituting objective of the analysis, the index for assessment of simultaneous development within agri-systems was elaborated. Such approach to analysed development on the base of some characteristic data for Polish and European conditions indicated possible consequences resulting from differences in introduced technical and biological advance expressed by milking capacity and dynamics of improved quality systems in dairy production. The proposed index to analyse and assess some aspects of simultaneous development of mutually connected elements of considered activity in dairy production constitutes one of the examples, how to consider and interpret results of the investigated dairy topics on the background of dairy agri-system.

 

Pečiulaitienė Nijolė, Ilona Miceikienė, Ramutė Mišeikienė. 2006. "Distribution of milk protein alfas1−kapa casein genotypes combinations and their link with productivity in Lithuanian dairy cattle breeds". Veterinarija ir zootechnika. T. 34 (56). 2006

 

KEYWORDS: milk, cattle, casein, polymerase chain reaction.

 

SUMMARY: In the study, to characterize distribution of bovine milk proteins Alphas1 - Kapa-casein genotypes combination was collected 427 (♀-394, ♂-33 ) unrelated animals from four Lithuanian dairy cattle breeds: LB&W–125, LR–181, LLG–70 and LWB–51. The identification of milk protein genotypes combination has been tested by methodology based on a polymerase chain reaction (PCR) and restriction fragment length polymorphism (RLFP). In the Lithuanian dairy cattle breeds multiple locus model- 8 milk protein genotypes of Alphas1-Kapa casein were investigated. The most common BBAA and BBAB genotypes of milk protein Alfas1−Kapa casein was found in all four investigated cattle breeds. Comparing productivity rate average, according of milk protein Alphas1-Kapa casein genotypes established, that BBBB genotype was associated with the higher fat (4,5±0,08%) and protein (3,5±0,04%) percentage in bovine milk. Meanwhile, statisticaly significant of Alfas1−Kapa casein genotype BBBE effected higher milk yield (5776±277kg), fat (251,4±14,4kg) and protein (187,9±938kg) amounts, compared with other genotypes. Multifactor dispersion analysis (ANOVA) was calculated for effects of milk protein Alphas1-Kapa casein genotypes combination for milk yield and milk composition. Milk protein Alphas1-Kapa casein genotypes combination showed higher influence for milk protein percentage 6,1% (P<0,001). After identification of quantitative (QTL) and qualitative trait locus in which existing genotypes determine manifestation of one or several quantitative traits. They can be used like genetics markers, which would let assess character of marks variability and consistent inheritance.

 

Wajda1Stanisław, Tomasz Daszkiewicz1, Gražina Januškevičienė2, Jurgita Dailidavičienė. 2006. "Fattening results and carcass quality of young bulls produced by mating polish black-and-white cows to charolaise and simental sires". Veterinarija ir zootechnika. T. 33 (55). 2006

 

KEYWORDS: bulls, Charolaise, Simental, progeny testing.

 

SUMMARY: The experiment was performed on 49 young crossbred bulls (Polish Black-and-White cows x Charolaise or Simental bulls). It constituted a part of a bull progeny testing program aimed at determining the suitability of beef bulls for crossing with Polish Black-and-White cows. In the study the progeny (8 to 11 young bulls) of three Simental and two Charolaise sires were examined. The young bulls were fattened from approx. 120 kg to approx. 500 kg body weight. During experiment the animals were kept in the same barn and were fed identically. It was found that the young bulls by Charolaise sires, compared with those by Simental sires, showed a tendency towards higher birth weights and higher gains. They also utilized fewer oat units per kg of body weight gain and were characterized by a higher carcass dressing percentage, higher proportions of primary elements in the carcass and better quality of meat. The evaluation of three Simental and two Charolaise bulls, performed on the basis of the slaughter value and meat quality of their progeny, confirmed their suitability for mating to Polish Black-and-White cows. This indicates that suitability for commercial crossing with dairy cows should be one of selection criteria in the case of beef bulls, as appropriate selection may substantially improve the fattening results and slaughter value of beef cattle.

 

Jukna Česlovas, Vigilijus Jukna, Aldona Baltušnikienė. 2006. "Comparative analysis of meat characteristics in modern selection of Lithuanian black-and-whites and Lithuanian Red Cattle". Veterinarija Ir Zootechnika. T. 33 (55).

 

KEYWORDS: breed, bulls, growth speed, carcass yield, meat quality.

 

SUMMARY: Comparative analysis of meat characteristics and quality in modern selection of Lithuanian Black-and-Whites and Lithuanian Red bulls was performed in 2004-2005. Bulls were raised at the same feeding and keeping conditions until 500 days of age. Afterwards bulls were measured, slaughtered and main indexes characterizing meat quality (chemical composition, pH, color, water binding capacity, shear force, cooking loss and index of protein) were evaluated. It was established that Lithuanian Black-and-Whites of modern selection were longer and their rear of the body was more developed. The bulls of both breeds have shown a different growth speed. The carcass yield of nonholsteinized Lithuanian Black-and-Whites was on 1.75 % higher compared to Lithuanian Red bulls. The yield of the ham portion of Lithuanian Red bulls was on 1.4 % higher compared to Lithuanian Black-and-Whites. Loin lean area of Lithuanian Red bulls was on 11 cm2 higher compared to Lithuanian Black-and-Whites. However, there were no statistical differences in chemical composition of meat. The tendency of Lithuanian Red for the higher shear force and for the lower cooking loss was observed. There were no differences in remaining indexes of meat quality.

 

Petraškienė Rasa, Ilona Miceikienė. 2006. "Influence of Holstein genes in bulls genotype on the reproduction traits of their daughters". Veterinarija ir Zootechnika. T. 33 (55).

KEYWORDS: amount of Holstein genes, black and white cattle, reproduction traits.

 

SUMMARY: Productivity and reproduction of herd have influence on dairy cattle herd profitability. Reproduction traits are dependent from genetic and non genetic factors. For improvement of breed, aspiring to increase productivity of dairy cows, the bulls having large amount of Holstein genes are used. The aim of the study – to test the influence of Holstein genes in bulls’ genotype on the reproduction traits of their daughters: age at the first calving, days open, calving interval, number of services from calving to conception and calvings results. The information of a pedigree, calvings, inseminations, and part of genes of improving breed in a genotype of bulls of black and white cattle in Lithuania was used. In Lithuania, to improve dairy cattle productivity, bulls having large amount of Holstein genes are used. As a result of such selection work we have productive cows, which have days open, number of services from calving to conception and calving interval larger than cows, which have not been improved with Holstein breed genes and characterized by lower productivity. In order to avoid reproduction problems it is very important to choose the optimal time for insemination after calving, taking into account productivity of cows.

 

Pandey A. K., Sharma R., Singh Y., Prakash B. B., Ahlawat S. P. S. 2006 "Genetic diversity studies of Kherigarh cattle based on microsatellite markers". Journal of Genetics, 85: 117–122.

 

KEYWORDS: Genetic diversity, Kherigarh cattle, microsatellite

 

SUMMARY: We report a genetic diversity study of Kherigarh cattle, a utility draught-purpose breed of India, currently declining at a startling rate, by use of microsatellite markers recommended by the Food and Agriculture Organization. Microsatellite genotypes were derived, and allelic and genotypic frequencies, heterozygosities and gene diversity were estimated. A total of 131 alleles were distinguished by the 21 microsatellite markers used. All the microsatellites were highly polymorphic, with mean (± s.e.) allelic number of 6.24 ± 1.7, ranging 4–10 per locus. The observed heterozygosity in the population ranged between 0.261 and 0.809, with mean (± s.e.) of 0.574 ± 0.131, indicating considerable genetic variation in this population. Genetic bottleneck hypotheses were also explored. Our data suggest that the Kherigarh breed has not experienced a genetic bottleneck in the recent past.

 

Malhotra Nupur, Dheer Singh, M. K. Sharma. 2006. "Cloning, Expression and Hormonal Regulation of Steroidogenic Acute Regulatory Protein Gene in Buffalo Ovary". Asian-Australian Journal of Animal Science, 20 (2): 184-193

 

KEYWORDS: StAR Gene, StAR mRNA, Semi-quantitative RT-PCR, Granulosa Cells, Ovary, Buffalo

 

SUMMARY: In mammalian ovary, steroidogenic acute regulatory (StAR) protein mediates the true rate-limiting step of transport of cholesterol from outer to inner mitochondrial membrane. Appropriate expression of StAR gene represents an indispensable component of steroidogenesis and its regulation has been found to be species specific. However, limited information is available regarding StAR gene expression during estrous cycle in buffalo ovary. In the present study, expression, localization and hormonal regulation of StAR mRNA were analyzed by semi-quantitative RT-PCR in buffalo ovary and partial cDNA was cloned. Total RNA was isolated from whole follicles of different sizes, granulosa cells from different size follicles and postovulatory structures like corpus luteum and Corpus albicans. Semi-quantitative RT-PCR analyses showed StAR mRNA expression in the postovulatory structure, corpus luteum. No StAR mRNA was detected in total RNA isolated from whole follicles of different size including the preovulatory follicle (>9 mm in diameter). However, granulosa cells isolated from preovulatory follicles showed the moderate expression of StAR mRNA. To assess the hormonal regulation of StAR mRNA, primary culture of buffalo granulosa cells were treated with FSH (100 ng/ml) alone or along with IGF-I (100 ng/ml) for 12 to 18 h. The abundance of StAR mRNA increased in cells treated with FSH alone or FSH with IGF-I. However, effect of FSH with IGF-I on mRNA expression was found highly significant (p<0.01). In conclusion, differential expression of StAR messages was observed during estrous cycle in buffalo ovary. Also, there was a synergistic action of IGF-I on FSH stimulation of StAR gene.

 

Xiju Shi, Chun Xia, Baoliang Pan, Ming Wang. 2006. "Interferon-α Genes from Bos and Bubalus bubalus". Animal Biotechnology, 17(1): 59 – 72

 

KEYWORDS: Bos and Bubalus bubalus, Interferon-α subtypes, Sequence comparison, Antiviral activity

 

SUMMARY: Interferon-α genes were cloned from six breeds of three species of two genera (three Chinese native cattle breeds of yellow cattle, wild yak and HuanHu domestic yak, one European breed of Holstein cow, and two water buffalo breeds of FuAn water buffalo and FuZhong water buffalo) by direct PCR. The PCR products were directly inserted into the expression vector to be sequenced and expressed. Sequence analysis showed that IFN-α genes of six clones were composed of 498 nucleotides, encoding a mature polypeptide with 166 amino acids. Compared with the published BoIFN-α subtypes, the IFN-α gene of Holstein cow had only one point mutation with the BoIFN-αA subtype. The IFN-α gene of yellow cattle was similar to the BoIFN-αD subtype with amino acid identity of 97.0% and may be considered as a new subtype, namely, BoIFN-αD1. The other four IFN-α genes, cloned from wild yak and HuanHu domestic yak, FuAn water buffalo, and FuZhong water buffalo, represented four new subtypes, namely, BoIFN-αI, BoIFN-αJ, BuIFN-α1, and BuIFN-α2, respectively. Each of the six clones was expressed in E. coli with molecular weight of 20kDa by SDS-PAGE and Western blot analyses. Antiviral activity assays showed that the six recombinant IFN-α (rIFN-α) all exhibited 1000 times higher antiviral activity in the MDBK/VSV cell line than in the CEF/VSV one. Moreover, the rIFN-αs could inhibit infectious bovine rhinotracheitis virus replication in the MDBK cell line using CPE inhibition method. The results suggested that rIFN-αs a potential agent for clinical application against virus diseases in cattle industry.

 

 

Kai Xue, Hong Chen, Shan Wang, Xin Cai, Bo Liu, Cun-Fang Zhang, Chu-Zhao Lei, Xin-Zhuang Wang, Yi-Min Wang, Hui Niu. 2006. "Effect of Genetic Variations of the POU1F1 Gene on Growth Traits of Nanyang Cattle". Acta Genetica Sinica, 33 (10): 901-907

KEYWORDS: Nanyang cattle, PCR-RFLP, POU1F1 gene, polymorphism, growth traits

SUMMARY: PCR-RFLP was applied to analyze the effect of the genetic variations of the POU1F1 gene on growth traits of 100 Nanyang cattle. The results showed that the 451 bp PCR product digested with Hinf I demonstrated polymorphism in the population, which was at Hardy-Weinberg equilibrium. Moreover, the frequencies of alleles A/B in the Nanyang population were 0.465/0.535. The association of the variations of the POU1F1 gene with the growth traits in the population was analyzed. The following parameters were greater in individuals with a genotype BB than in those with an genotype AB: birth weight, average weight increase before ablactation, body height at 12 months, body weight, body length, and chest girth at 6 months and 12 months (P<0.05). The body weight at 12 months was higher in the BB individuals than in the AA individuals (P <0.05). The body weight and body sizes also showed a trend of allele B> allele A in the other age groups. Therefore, the genotype BB maybe a dominant genotype and the allele B may be a dominant allele. These results imply that the allele B of the POU1F1 gene is likely to positively affect the growth traits.

 

 

R.D. Evans, P. Dillon, F. Buckle, D.P. Berry, M. Wallace, V. Ducrocq, D.J. Garrick. 2006. "Trends in milk production, calving rate and survival of cows in 14 Irish dairy herds as a result of the introgression of Holstein-Friesian genes". Animal Science, 82 (4): 423- 434

KEYWORDS: calving, fertility, genetic change, Holstein-Friesian, survival.

SUMMARY: Trends in milk production, calving rates, and survival were monitored on a potential 5580 primiparous and multiparous Holstein-Friesian dairy cows across 14 Irish seasonal spring-calving dairy farms between the years 1990 and 2001. Over this period calving rate to first service (CALV1) reduced by 0.96% per year (55 to 44%, P< 0.001), calving rate to first and second service (CALV12) reduced by 0.84% per year (77 to 70%, P< 0.001) and herd average parity number reduced by 0.10 lactation per year (4.3 to 3.5, P<0.001). The proportion of North American Holstein Friesian (NAHF) genes in the cows increased by 5.5% per year (8 to 63%, P<0.001), while pedigree index for milk yield (PIMILK) of the cows increased by 25 kg per year (P<0.001). The predicted difference of the sires of the cows for calving interval and survival increased by 0.5 days (P<0.001) and reduced by 0.12% (P<0.001) per year, respectively. A negative association was found between increased phenotypic milk yield, NAHF and PIMILK and reduced calving rates as assessed by CALV1 and CALV12. Increased proportion of NAHF genes exhibited a negative effect on survival (P<0.001) whereas increased levels of heterosis had a positive impact on survival (P<0.001). The results of the present study indicate that in seasonal calving herds in Ireland a need for direct selection on traits related to fertility and survival is required to arrest and reverse the declining trends in calving rates and survival.

 

 

Abe, Tsuyoshi, Hasebe, Hiroyuki, Kobayashi, Eiji. 2006. "Frequencies of bovine PrP gene polymorphisms in Holstein and Japanese Black bulls in Japan". Animal Science Journal, 77 (4): 395-398.

KEYWORDS: Bull, genotype frequency, Holstein, Japanese Black, prion

SUMMARY: We screened for Japanese Black and Holstein bull sire samples to detect single nucleotide polymorphisms (SNPs) involving animo-acid substitutions in the bovine prion gene in the entire coding region of the PRNP gene. Although three silent SNPs were found, we could not detect any SNP with animo-acid substitution. We also examined the polymorphism of the octapeptide repeat number in these samples. There was no homozygous bull with repeat number 5. The frequency of heterozygous (6/5) bulls was 8% in the Japanese Black bull and 4% in the Holstein bull, respectively. The bull samples used in this study contain popular elite sires, so it appears that the polymorphisms of prion protein (PrP) are rather difficult to find in these two breeds in Japan, except for polymorphism of the octapeptide repeat number.

 

 

Ferreira, W.J., Teixeira, N.M., Torres, R.A. 2006. "Estimate of genetic trend for milk production in Holstein in the State of Minas Gerais". Arquivo Brasileiro de Medicina Veterinária e Zootecnia, 58 (4): 599-606.

KEYWORDS: dairy cattle, genetic trend, REML, animal model.

SUMMARY: Production records from 75,567 lactations of 40,941 Holstein cows in 561 herds from 1980 to 2002 were used. Predicted cow and sire breeding values from an animal model were used to estimate genetic trend considering the four selection paths connecting two generations. The variance component estimates and breeding value predictions were obtained using the MTDFREML program package. The model of analysis accounted for the fixed effects of herd-year-season of calving, genetic group, age of calving as covariate (linear and quadratic) and the random effects of animal, permanent environment and error. The greatest annual genetic gain estimate was 57.7kg/yr for the path of sires of bulls from 1986 to 1991. For the path of dams of bulls, estimates were negative and for dams of cows changed from negative from 1970 to 1985 to 16.9kg/yr, from 1986 to 1999. When all paths of selection were combined, estimated annual genetic gain from 1970 to 1999 was 6.71± 3.78kg, corresponding to 0.1% of the average production. Estimates of genetic trend were much less than theoretically possible.

 

 

Cobuci, J.A., Costa, C.N., Teixeira, N.M. 2006. "Use of Legendre polynomials and Wilmink function in genetic evaluations for persistency of lactation in Holstein cows". Arquivo Brasileiro de Medicina Veterinária e Zootecnia, 58 (4): 614-623.

KEYWORDS: random regression model, genetic parameters, test day, Holstein cows, breeding value.

SUMMARY: Records of 11,023 first-parity Holstein cows belonging to 251 herds in the State of Minas Gerais were used to compare the Legendre polynomials and Wilmink function in random regression models (RRM) as for their effects in the estimate of genetic parameters and prediction of breeding values for nine types of persistency measurements and 305-day milk yield. The random regression test day models included the effect of herd-year-month test day, parameters of the function of Wilmink or 3th to 5th order Legendre polynomials to model fixed curves of the subclasses and 3th to 5th order Legendre polynomials to model genetic and permanent environmental effects. The Akaikes Information Criterion (AIC) and Bayesian Information Criterion (BIC) indicated the model with larger number of parameters as the one that best fitted the data of milk yield. Using the Legrendre polynomial model large variation was observed in the estimates heritabilities for most of the persistency measures. The estimates herdabilities varied from 0.11 to 0.33 to milk yield throughout the lactation, from 0.33 to 0.36 for the 305-day milk yield and, from 0.00 to 0.32 for persistency. Genetic correlations between persistency and 305-day milk yield differed according to the model and persistency measure. Compared the Legendre polynomials to the Wilmink function provided expressive changes in rank of animals for persistency of lactation.

 

 

J.J. Colleau, S. Moureaux. 2006. "Optimizing management of kinship and inbreeding coefficients in dairy cattle selection". INRA Productions Animales, 19: 3-14

KEYWORDS: kinship, inbreeding coefficients, dairy cattle.

SUMMARY: This paper describes the methodological approach followed for managing genetic variability in selected dairy cattle populations, when procreating young bulls (upward step), using service bulls (downward step) and selecting recently progeny-tested bulls (approval step). The objective was to minimize the average pairwise kinship coefficient in the existing population augmented by the individuals to be born from the planned matings, while setting their average genetic level to a pre-defined value. A posteriori full scale tests are carried out on the Holstein, Montbéliard, Norman breeds. In comparison with the most recent actual matings, the optimization method reduced the ave-rage kinship coefficients by about 20 to 30 % (upward and downward steps), while maintaining the average genetic level to its observed value. Optimized approval rejects an important proportion of the bulls already approved and accepts some new bulls, previously dismissed. The potential of using an overall EBV penalized for coancestry was investigated.

 

 

Oner, Yasemin, Elmaci, Cengiz, 2006. "Milk protein polymorphisms in Holstein cattle". International Journal of Dairy Technology, 59 (3): 180-182.

KEYWORDS: Genetic polymorphism, Holstein cattle, Milk protein

SUMMARY: Milk samples from 203 Holstein cows were phenotyped for genetic variants αs1-casein, β-casein, κ-casein and β-lactoglobulin using starch-gel electrophoresis. All of the four milk protein loci exhibited polymorphism with allele frequencies of 0.862 ± 0.017 for αs1-casein B, 0.966 ± 0.0009 for β-casein A, 0.712 ± 0.0224 for κ-casein A and 0.567 ± 0.0245 for β-lactoglobulin B. The mean heterozygosity estimated over all the four milk protein loci was 0.3015. Genetic equilibrium was observed among all of the loci investigated, except κ-casein. Chi-squared tests revealed that there was no significant linkage among studied milk protein phenotypes.

 

 

Molina, L H, Kramm, J, Brito, C, Carrillo, B, Pinto, M., Ferrando, A. 2006. "Protein composition of milk from Holstein–Friesian dairy cows and its relationship with the genetic variants A and B of κ-casein and β-lactoglobulin (Part I)". International Journal of Dairy Technology, 59 (3): 183-187.

KEYWORDS: Genetic variants, κ-Casein and β-lactoglobulin, Milk proteins

SUMMARY: The protein composition and the milk yield (morning milking) were studied in 10 Chilean Holstein–Friesian first lactation dairy cows during the spring season. In addition, the genetic variants A and B of κ-casein (κ-CN) and β-lactoglobulin (β-Lg) were also identified. The results showed that the casein content is significantly affected by the presence of B variant of κ-CN. Moreover, positive interactions between the B variant of κ-CN with AB of β-Lg and the combination of A κ-CN with AA of β-Lg for the total protein content, were found.

 

 

Molina, L H, Benavides, T, Brito, C, Carrillo, B & Molina, I. 2006. "Relationship between A and B variants of κ-casein and β-lactoglobulin and coagulation properties of milk (Part II)". International Journal of Dairy Technology, 59 (3): 188-191.

KEYWORDS: Coagulation properties, Genetic variants, κ-casein and β-lactoglobulin

SUMMARY: The purpose of this study was to relate the genetic variants A and B of κ-casein (κ-CN) and β-lactoglobulin (β-Lg) of the milk of 10 Chilean Holstein–Friesian cows and its coagulation properties (coagulation ability of milk, curd firmness and syneresis of the curd). The results showed that β-Lg AB phenotypes have a significant effect on the studied properties in comparison with the samples containing the AA phenotype. A and B variants of κ-CN did not have a significant effect on the coagulation properties, although there was a favourable interaction between β-Lg AB and κ-CN B.

 

 

C. Farke, E. Viturro, H. H. D. Meyer, C. Albrecht. 2006. "Identification of the bovine cholesterol efflux regulatory protein ABCA1 and its expression in various tissues". Journal of Animal Science, 84: 2887-2894

KEYWORDS: ABCA1, ATP-binding cassette transporter, Bos Taurus, cattle, quantitative PCR, sterol homeostasis

SUMMARY: The ATP-binding cassette transporter A1 (ABCA1) is known to play a significant role in cellular export of phospholipids and cholesterol in humans. The ABCA1 transporter might also play a crucial role in cellular cholesterol homeostasis in the cow or in the transfer of cholesterol into the milk, but its presence and tissue distribution in the bovine is unknown. Therefore, we studied the expression and distribution of the bovine ABCA1 transporter using quantitative PCR and sequenced the entire ABCA1 coding region. In addition, the proximal promoter was identified and screened for regulatory elements. Concordant with data from other mammalian species, bovine ABCA1 mRNA was expressed and detected in all tissues tested. The highest expression levels were detected in lung, esophagus, uterus, spleen, and muscle. Sequence analysis revealed that the open reading frame of this gene consists of 6,786 bases and encodes for a protein of 2,261 AA with a predicted molecular weight of 254 kDa. The deduced bovine ABCA1 protein shows the highest AA sequence homology with human (94%), mouse (93%), rat (92%), and chicken (85%). Analysis of the putative ABCA1 promoter region revealed potential transcription factor binding sites associated with ABCA1 transcription and lipid metabolism. This work could open new avenues for elucidating a potential role of ABCA1 in sterol homeostasis in the bovine organism.

 

 

R. Carvalheiro, E. C. G. Pimentel, V. Cardoso, S. A. Queiroz, L. A. Fries. 2006. "Genetic effects on preweaning weight gain of Nelore-Hereford calves according to different models and estimation methods". Journal of Animal Science, 84: 2925-2933.

KEYWORDS: crossbreeding, epistasis, genotype x environment interaction, heterosis, multicolinearity, ridge regression
SUMMAARY: Additive and nonadditive genetic effects on preweaning weight gain (PWG) of a commercial crossbred population were estimated using different genetic models and estimation methods. The data set consisted of 103,445 records on purebred and crossbred Nelore-Hereford calves raised under pasture conditions on farms located in south, southeast, and middle west Brazilian regions. In addition to breed additive and dominance effects, the models including different epistasis covariables were tested. Models considering joint additive and environment (latitude) by genetic effects interactions were also applied. In a first step, analyses were carried out under animal models. In a second step, preadjusted records were analyzed using ordinary least squares (OLS) and ridge regression (RR). The results reinforced evidence that breed additive and dominance effects are not sufficient to explain the observed variability in preweaning traits of Bos taurus x Bos indicus calves, and that genotype x environment interaction plays an important role in the evaluation of crossbred calves. Data were ill-conditioned to estimate the effects of genotype x environment interactions. Models including these effects presented multicolinearity problems. In this case, RR seemed to be a powerful tool for obtaining more plausible and stable estimates. Estimated prediction error variances and variance inflation factors were drastically reduced, and many effects that were not significant under ordinary least squares became significant under RR. Predictions of PWG based on RR estimates were more acceptable from a biological perspective. In temperate and subtropical regions, calves with intermediate genetic compositions (close to 1/2 Nelore) exhibited greater predicted PWG. In the tropics, predicted PWG increased linearly as genotype got closer to Nelore.

 

 

G. de los Campos, D. Gianola, B. Heringstad. 2006. "A Structural Equation Model for Describing Relationships Between Somatic Cell Score and Milk Yield in First-Lactation Dairy Cows". Journal of Dairy Science, 89:4445-4455

KEYWORDS: mastitis, structural equation model, recursive effect, variance component

SUMMARY: Relationships between production and diseases may involve recursive or simultaneous effects between traits. Four structural equation models (SEqM) for somatic cell score and milk yield, with varying specifications for the effects relating the 2 traits, were compared. Data consisted of repeated records of milk yield and somatic cell score of 33,453 first-lactation daughters of 245 Norwegian Red sires that had their first progeny test in 1991 and 1992. All models included random effects of the sire and of the cow and were fitted using the LISREL software. The Bayesian information criterion clearly favored a model with a recursive effect from somatic cell score on milk yield over the 3 other models fitted (absence of recursive effects, an effect from milk yield on somatic cell score, simultaneity of effects between the 2 traits). This provides evidence that the negative association between milk yield and somatic cell score is more likely due to an effect of infection (measured indirectly by the somatic cell score) on production than to a dilution effect. Estimates indicated that a mastitis event would reduce milk yield in the following 15 d by about 900 g/d. The estimated genetic (co)variances did not change sizably when the specification of recursive or simultaneous effects was varied. However, estimates of the phenotypic covariance were altered when a recursive effect from somatic cell score on milk yield was included in the model.

 

 

O. González-Recio, R. Alenda, Y. M. Chang, K. A. Weigel, D. Gianola. 2006. "Selection for Female Fertility Using Censored Fertility Traits and Investigation of the Relationship with Milk Production". Journal of Dairy Science, 89:4438-4444

KEYWORDS: fertility, bivariate censored threshold-linear model, production

SUMMARY: Bivariate models (censored linear-linear and censored threshold-linear) were used to estimate genetic parameters for production and fertility traits in the Spanish Holstein population. Records on 71,217 lactations from 41,515 cows were used: 30 and 36% of lactations were censored for days open (DO) and number of inseminations to conception (INS), respectively. Heritability estimates for production traits (milk, fat, protein) ranged between 0.18 and 0.25. Heritability of days to first service (DFS) and DO was 0.05, heritability of INS on the liability scale was 0.04. Genetic correlations between fertility traits were 0.41, 0.71, and 0.87 for DFS–INS, DO–INS, and DO–DFS, respectively. Days open had a larger genetic correlation (ranging from 0.63 to 0.76) with production traits than did DFS (0.47 to 0.59) or INS (0.16 to 0.23). Greater antagonism between production and DO may be due to voluntary management decisions for high-yielding cows, resulting in longer lactation lengths. Inseminations to conception appeared to be less correlated with milk production than were the other 2 female fertility traits. Including INS in a total merit index would be expected to increase genetic gain in terms of profit, but profit would decrease if either DO or DO and DFS were included in the index. Thus, INS is the trait to be preferred when selecting for female fertility. The genetic correlation between actual milk yield and 305-d standardized milk yield was 0.96 in the present study, suggesting that some reranking of sires could occur. Because the target of attaining a 12-mo calving interval, as implied by a 305-d standardized lactation length, is changing in the dairy industry, routine genetic evaluation of actual total lactation milk yield should be considered.

 

 

O. Cobanoglu, I. Zaitoun, Y. M. Chang, G. E. Shook, H. Khatib. 2006. "Effects of the Signal Transducer and Activator of Transcription 1 (STAT1) Gene on Milk Production Traits in Holstein Dairy Cattle". Journal of Dairy Science, 89:4433-4437
15.
KEYWORDS: signal transducer and activator of transcription 1 • signal transduction • quantitative trait • candidate gene

SUMMARY: A functional candidate gene approach was used to search for genes affecting milk production traits in Holstein dairy cattle. Signal transducer and activator of transcription 1 (STAT1) was chosen because of its involvement in the development of the mammary gland. Using the pooled genomic DNA sequencing approach, we identified a single nucleotide polymorphism. Genomic DNA was extracted from 1,292 sons obtained from the Cooperative Dairy DNA Repository and from 715 blood samples of daughters of 12 bulls obtained from the University of Wisconsin resource population. Daughter yield deviation data for the sons and yield deviation for the daughters were obtained for milk production traits from the USDA Animal Improvement Programs Laboratory. For the Repository population, allele C was associated with significant increases in milk fat and protein percentages. For the University of Wisconsin population, genotypes CC and CT were associated with significant increases in milk, fat, and protein yields. Results from this study are consistent with previous studies on the role of STAT1 in regulating the transcription of genes involved in milk protein synthesis and fat metabolism.
 

 

J. E. Pryce, B. L. Harris. 2006. "Genetics of Body Condition Score in New Zealand Dairy Cows". Journal of Dairy Science, 89:4424-4432
17.
KEYWORDS: random regression model • body condition score • fertility

SUMMARY: Body condition score (BCS) data were collected on 169,661 first-parity cows from herds participating in progeny testing schemes and linear type assessment. Genetic and residual variances for BCS estimated across time using a quadratic random regression model were found to be largest at the start of lactation. Heritability estimates ranged from 0.32 to 0.23 from d 1 to 200 of lactation, with a mean of 0.26. Genetic correlations between BCS and other traits were estimated using 2 approaches: 1) a multivariate analysis that included BCS and live weight, both adjusted for stage of lactation, 270-d cumulative yields of milk, fat, and protein, average somatic cell score, and 2 measures of fertility, and 2) a bivariate random regression analysis in which BCS was considered to be a longitudinal trait across time, with the same measurements as in approach 1 for all other traits. Genetic correlations of BCS with the 2 fertility traits were 0.43 and 0.50 using the multivariate analysis, the corresponding random regression estimates between BCS as a longitudinal trait across time and 2 measures of fertility were 0.35 to 0.44 and 0.40 to 0.49, and tended to increase with stage of lactation. Genetic correlations estimated using the random regression model fluctuated around the multivariate estimates for live weight and somatic cell score, which were 0.50 and –0.12, respectively. Genetic correlations estimated using the multivariate analysis of BCS with fat and protein yields were close to zero. With the random regression model, genetic correlations between BCS and fat and protein yields were positive at d 1 of lactation (0.16 and 0.08, respectively) and were negative by d 200 of lactation (–0.25 and –0.20, respectively). In pastoral production systems, such as those typical in New Zealand, there appears to be an advantage in the total lactation yields of fat and protein for cows of higher BCS in early lactation, which is likely to be because these cows have body reserves that are available to be mobilized in later lactation, when feed resources are sometimes limited.
 

 

B. Heringstad, I. M. Andersen-Ranberg, Y. M. Chang, D. Gianola. 2006. "Short Communication: Genetic Analysis of Nonreturn Rate and Mastitis in First-Lactation Norwegian Red Cows". Journal of Dairy Science, 89:4420-4423.
19.

KEYWORDS: female fertility, genetic correlation, mastitis, multivariate threshold model

SUMMARY: Associations between clinical mastitis (CM) and nonreturn rate within 56 d after first insemination (NR56) were examined in Norwegian Red (NRF) cows. Records on absence or presence of CM within each of the intervals, –30 to 30, 31 to 150, and 151 to 300 d after first calving, and records on NR56 for 620,492 first-lactation daughters of 3,064 NRF sires were analyzed with a Bayesian multivariate threshold liability model. Point estimates of genetic correlations between NR56 and the 3 CM traits were between –0.05 and –0.02. Residual correlations were close to zero, and correlations between herd-5-yr effects on NR56 and CM in the 3 lactation intervals ranged from –0.15 to –0.17. It appears that CM and NR56 in first lactation are independent traits.
 

 

M. H. Braunschweig, T. Leeb. 2006. "Aberrant Low Expression Level of Bovine ß-Lactoglobulin Is Associated with a C to A Transversion in the BLG Promoter Region". Journal of Dairy Science, 89: 4414-4419
21.
KEYWORDS: ß-lactoglobulin, genetic polymorphism, milk protein, expression

SUMMARY: ß-Lactoglobulin (ß-LG) is the major whey protein in cow’s milk. It is well established that the predominant 2 genetic variants, ß-LG A and B, are differentially expressed. Extensive investigation of the genetic variation in the promoter region of the BLG gene revealed the existence of specific haplotypes associated with the A and B variants, respectively. However, the genetic basis for the differential expression of BLG A and B alleles is still elusive. We have previously reported a quantitative ß-LG B variant, characterized by a very low ß-LG protein expression level. Here, we report that the corresponding BLG allele (BLG B*) shows a correspondingly low mRNA expression level. Comparative DNA sequencing of 7,670 bp of the BLG B* allele and the established BLG B allele revealed a unique difference of a C to A transversion at position 215 bp upstream of the translation initiation site (g.-215C>A). This mutation segregated perfectly with the differential phenotypic expression in a paternal half-sib family and could be confirmed in 2 independent cases. The sequence of the BLG B allele in the region of the mutation is highly conserved among 4 related ruminant species. The site of the mutation corresponds to a putative consensus-binding sequence for the transcription factors c-Rel and Elk-1 as predicted by searching the TRANSFAC database. The ß-LG B* site might be relevant in the natural production of milk of low ß-LG content.
 

 

Karthickeyan S.M.K., Saravanan, R., Thangaraju, P. 2006. "Characterization of Krishna Valley breed of cattle (Bos indicus) in south India using microsatellite markers". Livestock Research for Rural Development, 18, Article No. 151. Retrieved November 3, 2006, from http://www.cipav.org.co/lrrd/lrrd18/11/kart18151.htm
23.
KEYWORDS: Allele frequency, Krishna Valley, microsatellites,

SUMMARY: With the help of 25 microsatellite markers, a total of 50 Krishna Valley cattle were screened. The mean number of allele was found to be 4.72 ± 0.25 per microsatellite locus with the range of 3 to 7. The range in the allele size was from 94 (CSRM060) to 300 (ILSTS006) bp. These microsatellite alleles distributed at a minimum frequency of 0.0116 (ILSTS054) to a maximum of 0.8128 (ILSTS030). The mean polymorphism information content was found to be 0.6209 ± 0.03 ranging from 0.2583 (ILSTS030) to 0.7975 (INRA035). The overall means for observed and expected heterozygosities were 0.6683 ± 0.06 and 0.6569 ± 0.03 respectively. The markers used in the study were highly informative and high heterozygosity value is indicative of the higher amount of genetic variability that can be exploited even in population of small sizes.
 

 

Amimo J O, Mosi R O, Wakhungu J W, Muasya T K and Inyangala B O 2006. "Phenotypic and genetic parameters of reproductive traits for Ayrshire cattle on large-scale farms in Kenya". Livestock Research for Rural Development. Volume 18, Article #147. Retrieved November 3, 2006, from
http://www.cipav.org.co/lrrd/lrrd18/10/amim18147.htm


KEYWORDS: Age at first calving, Ayrshire, calving interval, genetic parameters and trends

SUMMARY: Data consisting of 2757 records from ten Kenyan Ayrshire herds made between 1980 and 2005 were used to examine environmental factors affecting age at first calving (AFC) and calving intervals (CI) and consequently estimate genetic and phenotypic parameters and trends. The overall means and standard errors for AFC and CI were 39.4 ± 7.2 months and 487.5 ± 151.6 days respectively. The respective heritability estimates were 0.091 ± 0.05 and 0.044 ± 0.032, while the repeatability estimate for CI was 0.096 ± 0.001. The genetic trends for CI and AFC were -0.6d/yr and -0.01mo/yr respectively and were both significant (P<0.001), indicating a decrease in mean breeding value over the study period. Phenotypic trends were -0.31 mo/yr and -0.35 d/yr for AFC and CI respectively though non-significant (P>0.05). The low heritability for CI and AFC indicated that temporary environmental influences were much greater than genetic influences or permanent environmental influences on these traits.
 

 

D. Gulisija, D. Gianola, K.A. Weigel, M.A. Toro. 2006. "Between-founder heterogeneity in inbreeding depression for production in Jersey cows". Livestock Science, 104 (3): 244-253
26.
KEYWORDS: Inbreeding depression, Between-founder heterogeneity, Jersey cows

SUMMARY: Severity of inbreeding depression depends on the hidden (i.e., recessive) genetic load carried by a population. If the load is distributed unevenly among founder genomes, or founder-lines were exposed to variable amounts of selection, descendants from different founders may be differentially affected by inbreeding. Between-founder heterogeneity in inbreeding depression for production traits and somatic cell score in milk (SCS) was studied using records from 59,788 Jersey cows. Inbreeding coefficients (F) were partitioned into components due to four founders, plus a remainder. A two-stage statistical analysis was performed. First, empirical best linear unbiased predictions (EBLUP) of residuals for milk, fat and protein yield, and for SCS, were computed using linear models including fixed effects of herd–year–season, age at calving and days in milk, and random additive genetic effects of individual cows. Second, models with total and partial inbreeding coefficients as predictor variables were fitted to EBLUP residuals, for each trait. Tests of differences between slopes indicated that regressions of milk, fat and protein yield on partial inbreeding coefficients were heterogeneous, SCS did not exhibit inbreeding depression. Hence, alleles contributing to inbreeding depression for production in this Jersey population seem to be associated with specific founders. This indicates that a homogeneous effect of inbreeding on production may be an incorrect statistical specification in genetic evaluation models that attempt to account for inbreeding depression. Furthermore, the observed variability between effects of partial inbreeding due to different founders implies that inbreeding effects on yield traits may be due to alleles with major effects.
 

 

J.V. Hansen, N.C. Friggens, S. Højsgaard. 2006. "The influence of breed and parity on milk yield, and milk yield acceleration curves". Livestock Science, 104 (1-2): 53-62
28.
KEYWORDS: Milk yield, Lactation, Parity, Breed, Cows

SUMMARY: This study had two aims. Firstly, we wanted to quantify the effects of breed and parity on lactation curves. A parametric model for describing milk yield for cows [Friggens, N., Emmans, G., Veerkamp, R., 1999. On the use of simple ratios between lactation curve coefficients to describe parity effects on milk production. Livest. Prod. Sci. 62, 1–13] was used. The data contained 155,051 daily records of milk yield from 318 cows of three different breeds, Danish Red, Danish Holstein and Jersey. There were 276, 230, and 98 lactation curves for parities 1, 2 and 3 respectively. For every cow lactation, the parameters of the model were estimated using a least squares procedure for non-linear models. The resulting parameters were analysed in a mixed linear model. Significant effects of parity were observed on the same two parameters as in Friggens et al. [Friggens, N., Emmans, G., Veerkamp, R., 1999. On the use of simple ratios between lactation curve coefficients to describe parity effects on milk production. Livest. Prod. Sci. 62, 1–13]. Breed was also found to have a significant effect on some of the parameters. However, there was no significant interaction between breed and parity. The second aim of the study was to evaluate the properties of acceleration in milk yield in the context of providing an indicator for physiological stress and subsequent health problems. Milk yield acceleration was highest around calving and also reflected trends for higher stress/risk for higher yielding cows.

 

 

S. Gäde, E. Stamer, W. Junge, E. Kalm. 2006. "Estimates of genetic parameters for milkability from automatic milking". Livestock Science, 104 (1-2): 135-146
30.
KEYWORDS: Genetic parameters, Milkability, Automatic milking, Serial data, Daily values, Milk yield

SUMMARY: Genetic parameters were estimated by restricted maximum likelihood with a multi-trait animal model for three milkability traits with serial data from an automatic milking system from a research farm (401 dairy cows) collected between September 2000 and June 2003 (320834 milkings). Furthermore, daily values for milk yield and milkability were formed from all single milkings resulting in 104 132 records and, subsequently, an estimation of genetic parameters was carried out based on these daily values. The resulting estimated heritability coefficients (based on daily values) are h2 = 0.55, h2 = 0.55 and h2 = 0.39 for average milk flow, maximum milk flow and milking time, respectively. The heritabilities are at a high level and thus breeding for good milkability makes sense. The genetic correlations between the three milkability traits are near unity with rg = 0.98 between average and maximum milk flow, rg = − 0.89 between average milk flow and milking time and rg = − 0.86 between maximum milk flow and milking time. Thus it may be sufficient to record only one of these traits in performance tests. The genetic correlations between milk yield and average milk flow, maximum milk flow and milking time are rg = 0.51, rg = 0.44 and rg = − 0.23, respectively. In future, serial data on milkability, already existing on many farms with automatic milk yield recording, should be used to greater extent for selective breeding with the aim of achieving good milkability.
 

 

J. Díez, J.J. del Coz, A. Bahamonde, C. Sañudo, J.L. Olleta, S. Macie, M.M. Campo, B. Panea, P. Albertí. 2006. "Identifying market segments in beef: Breed, slaughter weight and ageing time implications". Meat Science, 74 (4): 667-675
32.

KEYWORDS: Consumers, Preferences, Clustering, Acceptability, Machine learning, Artificial intelligence

SUMMARY: In this paper we propose a method to learn the reasons why groups of consumers prefer some beef products to others. We emphasise the role of groups since, from a practical point of view, they may represent market segments that demand different products. Our method starts representing people’s preferences in a metric space, there we are able to define a kernel based similarity function that allows a clustering algorithm to identify significant groups of consumers with homogeneous likes. Finally, in each cluster, we developed, with a support vector machine (SVM), a function that explains the preferences of those consumers grouped in the cluster. The method was applied to a real case of consumers of beef that tasted beef from seven Spanish breeds, slaughtered at two different weights and aged for three different ageing periods. Two different clusters of consumers were identified for acceptability and tenderness, but not for flavour. Those clusters ranked two very different breeds (Asturiana and Retinta) in opposite order. In acceptability, ageing period was appreciated in a different way. However, in tenderness most consumers preferred long ageing periods and heavier to lighter animals.
 

 

Forni, Selma and Albuquerque, Lucia Galvão De. 2006. "Environmental effects and genetic parameters estimates for days to calving in Nelore cattle". Revista Brasileira de Zootecnia,35 (4): 1329-1335.
34.
KEYWORDS: beef cattle, environmental effects, genetic parameters, reproductive traits.

SUMMARY: Data from a Nelore population was used to evaluate environmental effects and to estimate genetic parameters for days to calving (DPP). The influence of contemporary group, age at breeding season, month of last calving and weaning weight of the calf at the end of the breeding season were evaluated with fixed models. The weaning weight of the calf at the end of the breeding season was the only effect that did not influence DPP. Two different contemporary group (CG) definitions were also evaluated. Herd, year and season of breeding, management groups (birth, weaning and breeding) and mating type (multiple sires, single sire or artificial insemination) defined the first CG and the second CG included the same variables and sex of the calf. Variance components were estimated using restricted maximum likelihood method fitting univariate animal models, including or not non-calvers cows (which were penalized by adding 21 days to the largest DPP record in their management group). Heritability estimates ranged between 0.01 and 0.11. Exclusion of the permanent environmental effect from the model overestimated additive genetic variance. The method of assigning penalties to non-calvers cows was unsuitable, it resulted in reduced additive genetic variance. The results suggest that DPP is strongly influenced by the environment.
 

 

Boligon, Arione Augusti, Rorato, Paulo Roberto Nogara, Weber, Tomás. 2006. "Heritabilities for post-weaning daily gain and scrotal circumference at yearling age and genetic and phenotypic trends for post-weaning daily gain in Nellore-Angus crossbreds". Revista Brasileira de Zootecnia, 35 (4): 1323-1328. ISSN 1516-3598.
36.

KEYWORDS: breeding values, genetic progress, regression.

SUMMARY: Data consisting of 47.668 records of a Nellore-Angus crossbred population, raised in several regions of Brazil, from 1991 to 2001, were used to estimate heritability for post-weaning daily gain (ADG) and for scrotal circumference at yearling age (SCY) using REML. Genetic and phenotypic trends for ADG were also estimated. The model used to estimate heritability and breeding values (BVs) for ADG included the fixed effects of breed composition (defined by the percentage of contribution of the Nellore breed of the animal and his parents) and the contemporary group after weaning (herd, year/season of birth, sex and management group) and the random additive genetic animal and residual effects. The same model, including the fixed effects of weight and age of the animal at yearling, as covariates, was used for SCY. The average ages at weaning and yearling were respectively 215 and 528 days. The heritability estimates for ADG and SCY were 0.44 ± 0.02 and 0.22 ± 0.08, respectively. The annual genetic trend for ADG decreased up to the year of 1996 and increased then on. The phenotypic trend was 9.4 g/day/year.

 

 

H. S. Kong, J. D. Oh, S. G. Lee, Y. S. Hong, W. I. Song, S. J. Lee, H. C. Kim, B. H. Yoo, H. K. Lee, G. J. Jeon. 2006. "Association of Polymorphisms in the Bovine Leptin Gene with Ultrasound Measurements for Improving in Korean Cattle". Asian-Australian Journal of Animal Science, 19 (12): 1691-1695

KEYWORDS: Korean Native Cattle, Leptin Gene, Improvement of Cow, Real Time Ultrasound (RTU)

SUMMARY: The identification method that inflects real time ultrasound (RUT) and the potential application of marker assisted selection (MAS) for improvement of a cow population of Hanwoo (Korean Native cattle) was studied. The averages of RUT longissimus muscle area, RUT fat thickness, and RUT marbling score scanned at the 13th rib were 55.78 cm2, 3.70 mm and 3.83 scores, respectively. We investigated the effects of the two SNPs (Kpn2 I and Msp I) in the leptin gene on carcass traits for Hanwoo cows by using ultrasound measurements. Genotype CC of the Kpn2 I had a significantly higher effect on back fat thickness (4.23 mm) and longissimus muscle area (57.57 cm2) than genotype TT (3.14 mm, 53.93 cm2, respectively, p<0.05). Genotype AA of the Msp I had a significantly higher effect only on marbling score (5.37) than genotype AB (3.57, p<0.05) and BB (3.37, p<0.05). Significant effects of SNPs in the leptin gene were found for the ultrasound measures of body composition in live cattle.
 

 

A. K. Pandey, Rekha Sharma, Yatender Singh, B. Prakash, S. P. S. Ahlawat. 2006. "Evaluation of Genetic Variability in Kenkatha Cattle by Microsatellite Markers". Asian-Australian Journal of Animal Science, 19 (12): 1685-1690

KEYWORDS: Cattle, Genetic Variation, Kenkatha, Microsatellite

SUMMARY: Kenkatha cattle, a draft purpose breed, which can survive in a harsh environment on low quality forage, was explored genetically exploiting FAO-suggested microsatellite markers. The microsatellite genotypes were derived by means of the polymerase chain reaction (PCR) followed by electrophoretic separation in agarose gels. The PCR amplicons were visualized by silver staining. The allelic as well as genotypic frequencies, heterozygosities and gene diversity were estimated using standard techniques. A total of 125 alleles was distinguished by the 21 microsatellite markers investigated. All the microsatellites were highly 1.9 polymorphic with mean allelic number of 5.95 The
±(ranging from 3-10 per locus). observed heterozygosity in the population ranged between 0.250 and 0.826 0.171, with a mean of 0.540 Bottleneck was±signifying considerable genetic variation. examined assuming all three mutation models which showed that the population has not experienced bottleneck in recent past. The population displayed a heterozygote deficit of 21.4%. The study suggests that the breed needs to be conserved by providing purebred animals in the breeding tract.
 

 

Jong-Bok Kim, Chaeyoung Lee, Tsutomu Tsuyuki, Takeshi Shimogiri, Shin Okamoto, Yoshizane Maeda. 2006. "Sire-maternal Grandsire Model and Sire Model in Estimation of Genetic Parameters for Average Daily Gain and Carcass Traits of Japanese Black Cattle". Asian-Australian Journal of Animal Science, 19 (12): 1678 -1684.
40.

KEYWORDS: Sire-maternal Grand Sire Model, Sire Model, Heritability, Japanese Black Cattle

SUMMARY: The objectives of this study were to estimate genetic parameters and sire breeding values for average daily gain (ADG) and carcass traits using sire-maternal grandsire model with REML approach, sire model with REML approach, sire model without relationships among sires and with REML and ANOVA approach, and to investigate advantages and disadvantages of these methods. Data were collected from 42,325 Japanese Black steers and heifers finished and slaughtered from 1991 to 2004. Traits analyzed in this study were average daily gain (ADG) during the fattening period, live weight at slaughter (LW), cold carcass weight (CW), estimated lean yield percentage (LYE), longissimus muscle area (LMA), subcutaneous fat thickness (SFT), rib thickness (RT), and marbling score (BMS). Bivariate analyses were also performed to obtain genetic and phenotypic correlation coefficients among traits. Estimated breeding values were obtained from each model, and simple and rank correlations among breeding values from each model were calculated. Estimates of heritability using the four models ranged from 0.25 to 0.31 in ADG, from 0.21 to 0.24 in LW, from 0.23 to 0.27 in CW, from 0.10 to 0.17 in DP, from 0.40 to 0.42 in LYE, from 0.19 to 0.31 in LMA, from 0.31 to 0.34 in SFT, from 0.26 to 0.33 in RT, and from 0.18 to 0.44 in BMS. The differences in heritability estimates using the four models seemed to be feasible in ADG, CW, DP, LMA, RT, and BMS. Genetic correlation coefficients of ADG with CW, SFT, RT and BMS were moderate to high and positive while the genetic correlation coefficients between ADG and LYE was low and negative. Correlation coefficients of BMS with SFT were negligible for both genetic and phenotypic correlations. The correlations of estimates evaluated from sire models with those from sire-maternal grandsire model were not large enough to convincing that breeding values using a sire model were corresponding to those using a sire-maternal grand sire model. If information of maternal grand sires are not available, the sire model with incomplete pedigree information included only sire of sire (Model 2) is optimal among the sire models evaluated in this study.
 

 

Hyun Sub Cheong, Du-Hak Yoon, Lyoung Hyo Kim, Byung Lae Park, Eui Ryong Chung, Han Ju Lee, Il-Cheong Cheong, Sung-Jong Oh, Hyoung Doo Shin. 2006. "Leptin Polymorphisms Associated with Carcass Traits of Meat in Korean Cattle". Asian-Australian Journal of Animal Science, 19 (11): 1529-1535
42.

KEYWORDS: Leptin, Cold Carcass Weight, Marbling Score, Polymorphism

SUMMARY: Leptin has been investigated as a candidate gene for fat characteristics in beef cattle. Previously, we have reported 57 sequence variants discovered in Korean cattle (Bos Taurus coreanae). In this study, we examined the association between polymorphisms of leptin and carcass traits (cold carcass weight (CWT) and marbling score (Marb)) in Korean cattle. Among 57 polymorphisms, 11 common polymorphic sites were genotyped in our beef cattle (n = 437). Statistical analysis revealed that one single nucleotide polymorphism in coding exon (c.+411T>C (A137A)) showed a significant association with the yield trait, CWT. The C-bearing genotypes (CC or CT) of c.+411T>C (A137A) showed the higher CWT (p = 0.006). c.+150C>G (S50S) also showed a significant association with the quality trait, Marb (p = 0.01). Our findings suggest that polymorphisms in leptin might be one of the important genetic factors that influence carcass yield and quality in beef cattle, especially in CWT and Marb.
 

 

K. S. Seo, Y. N. Shen. 2006. "Correlation Analysis between the Breeding Value of Carcass Traits in Hanwoo (Korean Brown Cattle), Bos Taurus, L. and Spot Intensity on Two-dimensional Gel Electrophoresis". Asian-Australian Journal of Animal Science, 19 (10): 1404-1408

KEYWORDS: Hanwoo, Proteomics, Spot Intensity, Two-Dimensional Gel Electrophoresis, Breeding Value

SUMMARY: In order to investigate the genetic marker associated with economic performance in Hanwoo (Korean Brown Cattle), proteomic approach was used. Breeding values were estimated from performance tested steers. The top 20 and bottom 19 steers based on carcass weight (CW), eye muscle area (EMA), backfat thickness (BF) and marbling score (MS) evaluation for one progeny testing period was used. Meat samples dissected from longissimus dorsi muscles were taken from the slaughter house and analyzed for two-dimensional gel electrophoresis. A total of 102 significant spots out of total 146 on each gel were detected and compared with the reference gel (synthetic gel) to be evaluated. Four candidate spots for marbling score were identified: 205, 84, 204 and 198. The study confirmed the relationship between breeding values of economic traits of Hanwoo cattle and spot intensity.
 

 

Zhou Lei, Yuan-Yuan Yang, Zhong-Hao Li, Li-Juan Kong, Guan-Dong Xing, He-Shuang Di, Gen-Lin Wang. 2006. "Detection and Characterization of PCR-SSCP Markers of the Bovine Lactoferrin Gene for Clinical Mastitis". Asian-Australian Journal of Animal Science, 19 (10): 1399-1403

KEYWORDS: Cow, Lactoferrin, Clinical Mastitis, Polymorphism, PCR-SSCP

SUMMARY: A total of 80 cows, including 40 top mastitis resistant and 40 top mastitis susceptible animals as Group I and Group II, were selected from a population of 520 cows based on clinical mastitis occurrence. PCR-SSCP analysis on four fragments within the 5??region and two fragments of Exons 4,15 of bovine lactoferrin (bLF) revealed that four fragments-P1,P4,E4,E15-had polymorphisms which totally included six base mutations, and only two of them had significant differences in allele frequencies between resistant and susceptible groups, P1 (53.7% vs. 70.0%, p<0.05) and P4 (55.0% vs. 68.8%, p<0.05). Further study on these two promising markers combined with the milk performance traits of cows demonstrated that their selection would result in higher fat percentage (p<0.05), lower Somatic Cell Score (SCS) (p<0.05) and Clinical Mastitis Residuals (CMR) (p<0.01) indicating higher mastitis resistance and lower milk yield (p<0.05). The putative transcription factor binding sites in the 5??region were also studied by using MatInspector 7.2.2 software, and two signal pathways regulating the expression of bLF including the NF-??B pathway and nuclear hormone receptor pathway were predicted.
 

 

Sasazaki, S. Odahara, C. Hiura, F. Mukai, H. Mannen. 2006. "Mitochondrial DNA Variation and Genetic Relationships in Japanese and Korean Cattle". Asian-Australian Journal of Animal Science, 19 (10): 1394-1398
46.

KEYWORDS: mtDNA, Cattle, Japanese Black, Japanese Brown, Korean Cattle Phylogenetic Tree

SUMMARY: The complete mtDNA D-loop regions of Japanese and Korean cattle were analyzed for their mtDNA variations and genetic relationships. Sequencing the 30 Higo substrain and 30 Tosa substrain of Japanese Brown, respectively 12 and 17 distinct Bos haplotypes were identified from 77 polymorphic nucleotide sites. In order to focus on the relationships among Japanese and Korean cattle, two types of phylogenetic tree were constructed using individual sequences, first, a neighbor-joining tree with all sequences and second, reduced median networks within each Japanese and Korean cattle group. The trees revealed that two major mtDNA haplotype groups, T3 and T4, were represented in Japanese and Korean cattle. The T4 haplogroup predominated in Japanese Black and Japanese Brown cattle (frequency of 43.3-66.7%), while the T3 haplogroup was predominant (83.3%) and T4 was represented only twice in the Korean cattle. The results suggested that the mitochondrial origins of Japanese Brown were Japanese ancient cattle as well as Japanese Black in despite of the considerable introgression of Korean and European cattle into Japanese Brown.

 

 

47. Feng He, Dongxiao Sun, Ying Yu, Yachun Wang, Yuan Zhang. 2006. "Association between SNPs within Prolactin Gene and Milk Performance Traits in Holstein Dairy Cattle". Asian-Australian Journal of Animal Science, 19 (10):. 1384-1489

KEYWORDS: Holstein Dairy Cattle, Prolactinx, Prolactin, Haplotype, SNPs, Milk Performance Traits

SUMMARY: Prolactin plays an important role in mammary gland development, milk section initiation and maintenance of lactation, so the bovine prolactin gene is considered as a potential quantitative trait locus affecting milk performance traits in dairy cattle. In this study, to determine the association between prolactin and milk performance traits, the genetic polymorphisms of a part of the prolactin gene were detected in a population of 649 cows of Chinese Holstein Dairy Cattle. Three SNPs in the promoter and one SNP in the intron1 of prolactin were identified, which was A/C (-767), G/T (-485), C/A (-247), and C/T (427), respectively. Statistical results indicated that one of SNP within promote, CHBP2, was significantly associated with milk yield (p<0.01), fat yield (p<0.05), protein yield (p<0.01), and protein percentage (p<0.05). The cows with genotype BB of CHBP2 had significantly higher milk yield (p<0.01), fat yield (p<0.05), and protein yield (p<0.01) than those of cows with genotype AA, while cows with genotype AA showed the highest protein percentage (p<0.05). In addition, based on the nine major haplotypes constructed from the four SNPs, the association analysis between diplotypes and milk performance trait was carried out. Results showed that the least square mean for fat yield of diplotype H2H8 was significantly higher than those of other eleven diplotypes (p<0.05). Our findings implied that CHBP2 and H2H8 of prolactin would be useful genetic markers in selection program on milk performance traits in Holstein Dairy Cattle.
 

 

B. S. Ahn, B. S. Jeon, E. G. Kwon, M. Ajmal Khan, H. S. Kim, J. C. Ju, N. S. Kim. 2006. "Estimation of Genetic Parameters for Daily Milk Yield, Somatic Cell Score, Milk Urea Nitrogen, Blood Glucose and Immunoglobulin in Holsteins". Asian-Australian Journal of Animal Science, 19 (9): 1252 -1556 .
49.
KEYWORDS: Genetic Parameters, SCS, MUN, Glucose, IgG

SUMMARY: This study estimated the effects of parity (1-3) and stage of lactation (early, mid and late) on daily milk yield (DMY), somatic cell score (SCS), milk urea nitrogen (MUN), blood glucose, and immunoglobulin G (IgG), their heritabilities and genetic correlations between them in Holsteins (n = 200). Means and standard deviations of DMY, SCS, MUN, blood glucose, and IgG in the experimental herd were 23.35??.75 kg, 3.81??.00, 13.99??.68 mg/dl, 44.91??3.12 mg/dl, and 30.36??.72 mg/ml, respectively. DMY was the lowest in first parity, and in late lactation. SCS increased with parity, however, it was lowest in mid-lactation. MUN was lowest in first parity, and no difference was noted across stage of lactation. Blood glucose was similar between parities, however the highest blood glucose was observed during mid lactation. IgG level was significantly different between first and second parity, however, stage of lactation did not affect its level. Heritability of DMY was 0.16. Its genetic correlations with SCS and with blood glucose were -0.67 and 0.98, respectively. Heritability of SCS was 0.15. Genetic correlations of SCS with MUN, glucose, and IgG were -0.72, -0.59, and 0.68, respectively. Heritability of MUN was estimated to be 0.39 and had a genetic correlation of -0.35 with IgG. Heritabilities of blood glucose and IgG were 0.21 and 0.33, respectively. This study suggested that MUN, blood glucose and IgG could be considered important traits in future dairy selection programs to improve milk yield and its quality with better animal health and welfare. However, further studies are necessary involving more records to clarify the relationship between metabolic and immunological traits with DMY and its quality.
 

 

Akyüz, B., Ertugrul, O. 2006. "Detection of bovine leukocyte adhesion deficiency (BLAD) in Turkish native and Holstein cattle" Acta Veterinaria Hungarica, 54 (2): 173-178.

KEYWORDS: BLAD, Holstein, PCR, Turkey

SUMMARY: The purpose of this work was to study whether the bovine leukocyte adhesion deficiency (BLAD) allele is present in native cattle breeds and the Holstein breed in Turkey. Blood samples were obtained from 120 Holstein, 20 Brown Swiss, 20 Anatolian Black, 20 Turkish Grey, 20 South Anatolian Red and 20 East Anatolian Red cattle. The isolated DNA materials were multiplied in PCR using the primer developed by Kriegesmann et al. (1997). In order to determine the area of mutation in PCR products, the PCR products were digested with TaqI endonuclease enzyme. The resulting fragments were analysed on 2% agarose gel for the absence of a TaqI restriction site. It was found that two of the Holstein cattle (a bull and a cow) were heterozygote BLAD carriers. There was no homozygote BLAD animal. The BLAD allele was not found in the other breeds used in the study. The mutant BLAD allele frequency in the 120 Holstein cattle calculations was 0.0084.
 

 

Mao, Y-J., Chang, H., Yang, Z-P., Xu, M., Zhang, L., Chang, G-B., Song, W., Wang, D-L. 2006. " The Genetic Diversity and Phylogenetic Status of Luxi Cattle". Agricultural Sciences in China, 5 (8): 629-634

KEYWORDS: Luxi cattle; genetic diversity; cluster analysis

SUMMARY: A total of 87 individuals of Luxi cattle from Juanchen and Liangshan counties, Shangdong Province, China, were sampled by simple random sampling in typical colony. Twenty-one blood proteins and enzymes loci were detected by polyacrylamide gel electrophoresis (PAGE) and starch gel electrophoresis (SGE). In the meantime, the data of 7 loci of 13 cattle populations in China and other countries were collected and phylogeny relationships were studied. The results indicated that 9 out of 21 loci showed polymorphism (42.86%); the level of genetic variation in Luxi cattle population was relatively high, the mean heterozygosity was 0.1416. The Luxi cattle have a close phylogenetic relationship with the cattle populations of east and south of Asia, and this further confirmed the fact that Luxi cattle were the cross-breed between the Bos taurus and Bos indicus in China, but it is impossible that yellow cattle contained the blood of of Bali.
 

 

Brennan, K. M., Vella, K. R., Good, D. J. 2006. "Genetic analysis of NHLH2 and its putative role in bovine body weight control". Animal Genetics, 37 (s1): 24-27.

KEYWORDS: bovine chromosome 3, fat, Hen2, hypothalamus, marbling, NSCL-2, obesity, paraventricular nucleus, polymorphisms, promoter, quantitative trait loci

SUMMARY: The control of energy balance is fundamental to adult animals and is necessary for weight gain/loss, reproductive capacity and general health. In mice, targeted deletion of the neuronal transcription factor Nhlh2 results in adult-onset obesity because of reduced exercise and infertility because of reduced sexual behaviour. Nhlh2 (NHLH2 for humans) is expressed in the hypothalamus, particularly in neurons that have been shown to regulate energy balance. We have cloned the bovine Nhlh2 gene (bNHLH2) and we have shown that bNHLH2 is also expressed in the hypothalamus. Phylogenetic analysis of Nhlh2 reveals that it is very highly conserved in humans, mice, chimps and cattle, and found in organisms with simpler nervous systems, including Caenorhabditis elegans and Drosophila. Using a cattle–human comparative map and online databases, we have evidence that bNHLH2 is located near a quantitative trait locus for marbling on bovine chromosome 3 between microsatellite markers BM723 and BMS963. Cloning of the bNHLH2 gene from Holstein cattle and a mixed breed individual and comparison with Hereford sequences shows that the gene is highly conserved among bovine breeds.
 

 

Geldermann, H., He, H., Bobal, P., Bartenschlager, H., Preuß, S. 2006. "Comparison of DNA variants in the PRNP and NF1 regions between bovine spongiform encephalopathy and control cattle". Animal Genetics, 37 (5): 469-474.

KEYWORDS: bovine spongiform encephalopathy, cattle, NF1, PRNP, transmissible spongiform encephalopathy,

SUMMARY: DNA from 252 bovine spongiform encephalopathy (BSE) cattle and 376 non-diseased control cattle were genotyped for nine loci in the prion protein (PRNP) gene region, three loci in the neurofibromin 1 (NF1) region and four control loci on different chromosomes. The allele and genotype frequencies of the control loci were similar in BSE and control cattle. In the analysed 7.4 Mb PRNP region, the largest differences between BSE and control cattle were found for the loci REG2, R16 and R18, which are located between +300 and +5600 bp, spanning PRNP introns 1 to 2. Carriers of the REG2 genotype 128/128 were younger at BSE diagnosis than those with the other genotypes (128/140 or 140/140). The predominant haplotype REG2 128 bp–R18 173 bp occurred more frequently (P < 0.001), and the second-most frequent haplotype (REG2 140 bp–R18 175 bp) occurred less frequently (P < 0.05) in BSE than in control cattle. The largest frequency differences between BSE and control groups were observed in the Brown Swiss breed. Across all breeds, most of the same alleles and haplotypes of the PRNP region were associated with BSE. In the 23-cM NF1 region, associations with BSE incidence were found for the RM222 allele and for the DIK4009 genotype frequencies. Cattle carrying RM222 genotypes with the 127- or 129-bp alleles were about half a year older at BSE incidence than those with other genotypes. Across the breeds, different alleles and genotypes of the NF1 region were associated with BSE. The informative DNA markers were used to localize the genetic disposition to BSE and may be useful for the identification of the causative DNA variants.
 

 

Lenstra, J. A. 2006. "Marker-assisted conservation of European cattle breeds: an evaluation". Animal Genetics, 37 (5): 475-481.

KEYWORDS: cattle, conservation, genetic diversity, kinship, microsatellite, Weitzman

SUMMARY: Two methods have been developed for the assessment of conservation priorities on the basis of molecular markers. According to the Weitzman approach, contributions to genetic diversity are derived from genetic distances between populations. Alternatively, diversity within and across populations is optimized by minimizing marker-estimated kinships. We have applied, for the first time, both methods to a comprehensive data set of 69 European cattle breeds, including all cosmopolitan breeds and several local breeds, for which genotypes of 30 microsatellite markers in 25–50 animals per breed have been obtained. Both methods were used to calculate the gain in diversity if a breed was added to a set of nine non-endangered breeds. Weitzman-derived diversities were confounded by genetic drift in isolated populations, which dominates the genetic distances but does not necessarily increase the conservation value of a breed. Marker-estimated kinships across populations were less disturbed by genetic drift than the Weitzman diversities and assigned high conservation values to Mediterranean breeds, which indeed have genetic histories that differ from the non-endangered breeds. Prospects and limitations of marker-assisted decisions on conservation priorities are discussed.
 

 

Lambeth, L. S., Wise, T. G., Moore, R. J., Muralitharan, M. S., Doran, T. J. 2006. "Comparison of bovine RNA polymerase III promoters for short hairpin RNA expression". Animal Genetics, 37 (4): 369-372.

KEYWORDS: bovine, RNA interference, short hairpin RNA, U6 and 7SK , promoters

SUMMARY: RNA interference (RNAi) mediated by DNA-based expression of short hairpin RNA (shRNA) is a powerful method of sequence-specific gene knockdown. A number of vectors for expression of shRNA have been developed that feature promoters from RNA polymerase III (pol III)-transcribed genes of mouse or human origin. To advance the use of RNAi as a tool for functional genomic research and for future development of specific therapeutics in the bovine species, we have developed shRNA expression vectors that feature novel bovine RNA pol III promoters. We characterized two bovine U6 small nuclear RNA (snRNA) promoters (bU6-2 and bU6-3) and a bovine 7SK snRNA promoter (b7SK). We compared the efficiency of each of these promoters to express shRNA molecules. Promoter activity was measured in the context of RNAi by targeting and suppressing the reporter gene encoding enhanced green fluorescent protein. Results show that the b7SK promoter induced the greatest level of suppression in a range of cell lines. The comparison of these bovine promoters in shRNA expression is an important component for the future development of bovine-specific RNAi-based research.
 

 

Schlumbaum, A., Turgay, M., Schibler, J. 2006. "Near East mtDNA haplotype variants in Roman cattle from Augusta Raurica, Switzerland, and in the Swiss Evolène breed". Animal Genetics, 37 (4): 373-375.

KEYWORDS: ancient DNA, Bos Taurus, genetic diversity, mitochondrial DNA, Roman cattle

SUMMARY: Typical Near East mitochondrial haplotypes of the T2 lineage were found in one cattle metacarpus sample from the Roman period and in two present-day Evolène cattle in Switzerland. Sequences from eight additional Evolène and four Raetian Grey aligned to the European haplotype T3. Analysis of nucleotide diversity within the mitochondrial D-loop of both studied Swiss cattle breeds revealed high haplotype diversity and similar diversity to a European cattle reference group. Mitochondrial T3 haplotypes radiated star-like from two similarly frequent haplotypes, possibly indicating two different expansion routes. The breed structure of Evolène cattle can be explained either by an introduction of diverse female lineages from the domestication centre or by later admixture. The introduction of the Near East lineage to Switzerland must have happened during the Roman time or earlier.
 

 

Lirón, J. P., Bravi, C. M., Mirol, P. M., Peral-García, P. & Giovambattista, G. 2006. "African matrilineages in American Creole cattle: evidence of two independent continental sources". Animal Genetics, 37 (4): 379-382.

KEYWORDS: Bos Taurus, Creole cattle, migration routes, mitochondrial DNA , phylogeny

SUMMARY: In order to clarify the historical origin and phylogeographic affinities of Creole cattle matrilineages throughout the American continent, we analysed published D-loop mtDNA sequences (n = 454) from Creole, Iberian and African cattle breeds. The Western European T3 haplogroup was the most common in American Creole cattle (63.6%), followed by the African T1 (32.4%) and the Near Eastern T2 haplogroups (4%). None of the sequences were found in Bos indicus types. Within the African T1 haplogroup there were two subclades, T1a and T1*, whose geographic distribution in America was clearly disjointed. T1a is a highly divergent clade originally reported for Creole cattle from Brazil and the Lesser Antilles, but whose geographic distribution in Africa remains unknown. In contrast, lineages attributable to T1* are restricted in America to the region colonized by the Spaniards. We propose a new hypothesis for the origins of Creole cattle that summarizes all previously published historical and genetic data. While the African T1* fraction in Creole cattle may have arrived in America through the Iberian breeds, the divergent T1a lineages may have been introduced by Portuguese and other European crowns from some unknown, not-yet-sampled African location. Additional molecular studies will be required for pinpointing the specific African regional source.
 

 

Li, M. H., Adamowicz, T., Switonski, M., Ammosov, I., Ivanova, Z., Kiselyova, T., Popov, R., Kantanen, J. 2006. "Analysis of population differentiation in North Eurasian cattle (Bos taurus) using single nucleotide polymorphisms in three genes associated with production traits". Animal Genetics, 37 (4): 390-392.

KEYWORDS: cattle, microsatellite, population differentiation, quantitative trait loci, single nucleotide polymorphism

SUMMARY: Single nucleotide polymorphisms (SNPs) in growth hormone 1 (GH1), insulin-like growth factor 1 (IGF1) and leptin (LEP), all candidates for production traits in cattle, were characterized in North Eurasian cattle breeds. Allele frequencies of IGF1 exhibited significant (P < 0.05) deviation from neutral expectation and therefore, might be associated with divergence in North Eurasian cattle because of genetic selection. Allele frequencies and lower heterozygosity of LEP may indicate a recent introduction of an alternative allele in this geographic region. Locus FST estimates were highest for IGF1 (0.151, σ = 0.042) and lowest for GH (0.062, σ = 0.020). Our results suggest a slightly higher population differentiation across the candidate genes (FST = 0.108) than across microsatellites (FST = 0.095), possibly because of selection and stochastic effects.
 

 

Michal, J. J., Zhang, Z. W., Gaskins, C. T., Jiang, Z. 2006. "The bovine fatty acid binding protein 4 gene is significantly associated with marbling and subcutaneous fat depth in Wagyu x Limousin F2 crosses". Animal Genetics, 37 (4): 400-402.

KEYWORDS: association, beef cattle, fatty acid binding protein 4, marbling, subcutaneous fat depth

SUMMARY: Fatty acid binding protein 4 (FABP4), which is expressed in adipose tissue, interacts with peroxisome proliferator-activated receptors and binds to hormone-sensitive lipase and therefore, plays an important role in lipid metabolism and homeostasis in adipocytes. The objective of this study was to investigate associations of the bovine FABP4 gene with fat deposition. Both cDNA and genomic DNA sequences of the bovine gene were retrieved from the public databases and aligned to determine its genomic organization. Primers targeting two regions of the FABP4 gene were designed: from nucleotides 5433–6106 and from nucleotides 7417–7868 (AAFC01136716). Direct sequencing of polymerase chain reaction (PCR) products on two DNA pools from high- and low-marbling animals revealed two single nucleotide polymorphisms (SNPs): AAFC01136716.1:g.7516G>C and g.7713G>C. The former SNP, detected by PCR-restriction fragment length polymorphism using restriction enzyme MspA1I, was genotyped on 246 F2 animals in a Waygu × Limousin F2 reference population. Statistical analysis showed that the FABP4 genotype significantly affected marbling score (P = 0.0398) and subcutaneous fat depth (P = 0.0246). The FABP4 gene falls into a suggestive/significant quantitative trait loci interval for beef marbling that was previously reported on bovine chromosome 14 in three other populations.
 

 

Morris, C. A., Cullen, N. G., Hickey, S. M., Dobbie, P. M., Veenvliet, B. A., Manley, T. R., Pitchford, W. S., Kruk, Z. A., Bottema, C. D. K., Wilson, T. 2006. "Genotypic effects of calpain 1 and calpastatin on the tenderness of cooked M. longissimus dorsi steaks from Jersey × Limousin, Angus and Hereford-cross cattle". Animal Genetics, 37 (4): 411-414.

KEYWORDS: calpain 1, calpastatin, cattle, meat, tenderness

SUMMARY: Single nucleotide polymorphisms (SNPs) in the calpain 1 (CAPN1) and calpastatin (CAST) genes were studied to determine their effects on meat tenderness in Bos taurus cattle. Strip loins (M. longissimus dorsi) were removed from cattle in four resource populations after slaughter (n = 1042), aged under controlled conditions until fixed times after rigor mortis, cooked and measured using a tenderometer. Animals were genotyped for the CAPN1 SNP c.947C>G (p.Ala316Gly; AF252504) and for the CAST SNP c.2959A>G (AF159246). Frequencies of CAPN1 C alleles ranged from 23% to 68%, and CAST A alleles from 84% to 99.5%. From all data combined, the CAPN1 CC genotype (compared with the GG genotype) was associated with a 20.1 ± 1.7% reduced average shear force at intermediate stages of ageing (P < 0.001) and with a 9.5 ± 1.3% reduction near ultimate tenderness (P < 0.001). The heterozygote was intermediate. For CAST, corresponding values for AA compared with AG genotypes were reductions of 8.6 ± 2.0% and 5.1 ± 1.6% respectively (both P < 0.001), but there were too few GG genotypes for comparison. There were small interactions between the CAPN1 and CAST genotypes. For the CAPN1 and CAST genotypes combined, the maximal genotype effect in average shear force was 25.7 ± 5.5% (P < 0.001) at intermediate stages and 15.2 ± 4.8% near ultimate tenderness (P < 0.01).
 

 

Moreira, V.H., Bravo-Ureta, B.E., Carrillo, B. L. 2006. "Technical efficiency measures for small dairy farms in Southern Chile: A stochastic frontier analysis with unbalanced panel data". Archivos de Medicina Veterinaria, 38: 25-32.

KEYWORDS: Stochastic frontiers; technical efficiency; panel data; dairy farms.

SUMMARY: This paper uses a stochastic production frontier model to measure technical efficiency and technological change for a sample of small dairy farms in Southern Chile. The data is a highly unbalanced panel including 48 farmers with a total of 92 observations covering the period from 1996/97 to 2001/02. All farmers in the sample are members of the Paillaco Farm Management Center (FMC). In the preferred model, the inefficiency term has a half-normal distribution, there is no agro-climatic effect and the presence of technical inefficiency is highly significant and time variant. Average technical efficiency ranges from 77% (1996/97) to 69% (2000/01) and technological change is significant and increases at an average annual rate of 8.6% for the period (1996/2002). On average, the farmers in the sample from Paillaco (Southern Chile) are operating at a sub optimal size given that the computed returns to size parameter is equal to 1.12.
 

 

Gonzalez-Stagnaro, C., Goicochea Llaque, J., Rodríguez-Urbina, M., Madrid Bury, N., González Villalobos, D. 2006. "Introduction to breeding in crossbred dual purpose heifers". Archivos Latinoamericanos de Producción Animal [Online] 14:1. Available: http://www.alpa.org.ve/ojs/viewarticle.php?id=344.

KEYWORDS: crossbred dual purpose heifers, breeding.

SUMMARY: This study evaluated 21,667 observations of age (EI) and weight (PI) of introduction to service in heifers from 47 dual purpose bovine herds, located in four areas of dry and humid tropical forest environments. Effects studied were those of geographic area (Laberinto, Perija, Costa Oriental and Sur del Lago); management system: traditional (ST) and improved (SM); breed predominance (Holstein, Brown Swiss, Brahman and Carora); season of birth and of introduction to service; birth weight (PN); and weaning age (ED) and weight (PD). Mean EI was 30.9 ± 5.9 m and was earlier (P < 0.001) in Laberinto and Perija than in the other regions, in SM than ST (27.3 ± 02 vs.31.6 ± 0.01 m), and in Brown Swiss and Brahman than in Holsteins (32.0 ± 01 m). Mean PI was 353.3 ± 31.9 kg and was heavier (P<0.001) in Laberinto to (383.4 ± 1.5 kg), in SM than ST (364.6± 1.0 vs. 349.7 ± 0.5 kg), and Holstein and Brown Swiss (354.3 ± 0.7 and 357.6 ± 1.2 kg). EI was related to PI and dependent on daily weight gain (GDP); 48% of the heifers had GDP of 251 to 350 g/d an only 9.2% gained > 350 g/d. A GDP of > 350 g/d resulted in earliest EI (24.4 ± 0.4 m) and heaviest PI (375.8 ± 1.8 kg). Birth and weaning in dry season delayed EI. Lower EI and higher PI during rainy season were related to grazing conditions. At ED of < 10 m or > 10 m, EI increased (29.2 ± 0.4 to 34.6 ± 0.4 m) and PI decreased (366.2 ± 2.0 to 358.6 ± 2.0 kg); while in heifers with PD < 180 and > 180 kg, EI was 29.9 ± 0.2 and 27.8 ± 0.2 m, and PI was 353.5 ± 0.9 and 359.1 ± 1.1 kg (P<0.001). Adequate feeding management improved EI and PI results.
 

 

Teixeira, C., Oliveira, D., Quirino, C. 2006. "Double muscling II. –Genetic determination". Archivos Latinoamericanos de Producción Animal [Online] 14:1. Available:
http://www.alpa.org.ve/ojs/viewarticle.php?id=472.

KEYWORDS: Double muscling, Genetic determination

SUMMARY: Mutations in the myostatin gene that increase muscle mass, charaterize double muscling or muscular hypertrophy phenotipe in some cattle breeds. Despite of some restrictions related to calving easy, carcass of these animals are considered superior, resulting in higher meat yield, higher proportion of expensive meat cuts and lean and tender meat, and have been used in production systems worldwide. The possibility to identify the carriers of the mutation has been decisive in meat production systems. The mutation was identified in others species of economic interest, such as sheep, demanding new research and strategies to improve the production systems.
 

 

Casas, E. 2006."Application of genomics to identify genes influencing economically important traits in livestock". Archivos Latinoamericanos de Producción Animal [Online] 14:1. Available:
http://www.alpa.org.ve/ojs/viewarticle.php?id=469.

KEYWORDS: genomics, traits, livestock.

SUMMARY: The objective of this paper was to review the current status of the tools used to identify genes influencing economically important traits in livestock, and show an example using markers developed for meat tenderness. The current linkage maps comprise 4,000 microsatellites and 1,000 single nucleotide polymorphisms. The bovine genome sequence is now available. This information will be used to identify genes affecting production traits. It will also enable to identify causative mutations of the traits of interest. There are different methods to identify quantitative trait loci (QTL). Maximum likelihood and mean squares are the most commonly used. Quantitative trait loci have been detected in several bovine chromosomes. μ–calpain is a gene that has been associated with meat tenderness. Marker information can be now incorporated in animal breeding programs.
 

 

Cunha, E.E., Euclydes, R.F., Torres, R.A. 2006. "Genetic evaluation of beef cattle herds through simulated data". Arquivo Brasileiro de Medicina Veterinária e Zootecnia, 58:381-387.

KEYWORDS: bovine; computer simulation; genetic gain; inbreeding; selection method.

SUMMARY: The program GENESYS was utilized to simulate herds of beef cattle selected, for five generations, by individual selection or selection based on best linear unbiased prediction (BLUP). Average phenotypic values and inbreeding average of simulated animals from these methods were compared. The simulated quantitative trait was daily weight gain with average initial phenotypic value of 1kg and heritability of .35. The values of sexual ratio in the selection populations were 1:50 and 1:25 (male: females), corresponding to effective population sizes of 23.53 and 57.69 animals, respectively. The individual genetic gains were larger for animals under BLUP selection as a result of higher accuracy of the predicted genetic values. No significant difference between the effective population sizes for average phenotypic values by generation within each selection method was found. The inbreeding coefficient increased within both selection methods and effective sizes. Larger increase and oscillation were observed for selection based on BLUP in the population with smaller effective size. Although a short term selection program was simulated, the results allowed to discriminate combinations which resulted in larger inbreeding increment.
 

 

Dias, J.C., Andrade, V.J., Fridrich, A.B. 2006. "Genetic parameter estimates for reproductive traits in young Nelore bulls". Arquivo Brasileiro de Medicina Veterinária e Zootecnia, 58: 388-393.

KEYWORDS: testicular biometry; seminal traits; genetic correlation; heritability; Nelore.

SUMMARY: Heritabilities and genetic correlations between performance and reproductive traits were estimated using Multiple Trait Derivative-Free Restricted Maximum Likelihood methodology in 579 pasture-raised Nelore bulls that were 19 to 39 months of age. Traits were breeding soundness evaluation (BSE), scrotal circumference (SC), testicular consistency (TC), testicular volume (TV), testicular shape (TS), length and width of right and left testicles, and semen traits including motility (Mot), vigor (Vig), major (MD) sperm defects, minor (mD) sperm defects and total (TD) sperm defects. Heritability estimates were 0.46; 0.10; 0.08; 0.16; 0.09; 0.11 and 0.10 for TC, Mot, Vig, MD, mD, TD and BSE, respectively. Genetic correlations between SC and: body weight (BW), TV, Mot, Vig, mD, TD and BSE were 0.72; 0.99; 0.72; 0.60; -0.67; -0.12 and 0.64, respectively, showing favorable associations between SC and the other traits. Genetic correlations between BSE and: BW, TV, MD and TD were 0.19; 0.71; -0.47 and -0.58, respectively. Results suggest that selection for body weight in Nelore bulls should not hamper fertility, nor should selection for reproductive traits hamper growth.
 

 

Bittencourt, T.C.C., Lobo, R.B. and Bezerra, L.A.F. 2006. "Economic values for breeding goal traits for Brazilian beef cattle production". Arquivo Brasileiro de Medicina Veterinária e Zootecnia, 58: 58: 196-204.

KEYWORDS: beef cattle; breeding objective; economic value.

SUMMARY: Breeding objectives were developed for beef cattle production under typical economic and environmental conditions of central Brazil. The traits considered were: calves weaned per cow/year (NCW), weaning weight (WW), carcass weight (CW) and food intake. In the study, two systems were examined, a cow-calf system (surplus calves sold after weaning) and a cow-calf enterprise (in which surplus calves are raised for slaughter). In the first, income is from the sale of male calves and surplus heifers after weaning and of culled cows. In the second, the income is from the sale of steers, surplus heifers and culled cows. For both situations, the profit (US$/cow/year) was estimated by the difference between revenue and costs. The economical values (EV) were calculated as the change in profit resulting from a unit change in each trait, as other traits remained unchanged. The trait with greatest economic value was NCW, followed by food intake, CW and WW. The order of importance when values were in additive genetic standard deviation units were feed intake, CW, NCW and WW.
 

 

Meridy J. Kadel, David J. Johnston, Heather M. Burrow, Hans-U. Graser, Drewe M. Ferguson. 2006. "Genetics of flight time and other measures of temperament and their value as selection criteria for improving meat quality traits in tropically adapted breeds of beef cattle". Australian Journal of Agricultural Research, 57(9): 1029–1035.

KEYWORDS: flight speed, tenderness, heritability, genetic correlation.

SUMMARY: Flight time, an objective measure of temperament, was recorded in 3594 Brahman, Belmont Red, and Santa Gertrudis heifers and steers. Two subjective measures of temperament (crush score and flight speed score) were also available for over 2000 of these animals. Temperament measures were recorded post-weaning (average age 8 months) and again at the start of finishing (average age 19 months) on a subset of the animals. Nine meat quality traits were measured on these animals and included measures on 2 different muscles [M. longissimus thoracis et lumborum (LTL) and M. semitendinosus (ST)]. The heritability of flight time measured post-weaning and at the start of finishing was 0.30 and 0.34, respectively, with a repeatability of 0.46 across the measurement times. Heritabilities for scored temperament traits were 0.21, 0.19, and 0.15 for post-weaning flight speed score, post-weaning crush score, and start of finishing crush score, respectively. Genetic correlations across measurement times for flight time were 0.98 and 0.96 for crush score, indicating a strong underlying genetic basis of these temperament measures over time; however, the corresponding phenotypic correlations were lower (0.48 and 0.37, respectively). Longer flight times (i.e. better temperament) were genetically correlated with improved tenderness (i.e. lower shear force and higher tenderness scores), with genetic correlations of –0.42 and 0.33 between LTL shear force, and Meat Standards Australia (MSA) tenderness, respectively. Genetic correlations between post-weaning crush score and the same meat quality traits were 0.39 and –0.47, respectively. However, genetic and phenotypic correlations between measures of temperament and other meat quality traits were generally low, with the exception of crush scores with LTL Minolta a* value (–0.37 and –0.63 for post-weaning and start of finishing measurement time, respectively). Predicted correlated responses of –0.17 kg LTL shear force and 2.6 MSA tenderness points per generation were predicted based on the genetic parameter estimates and a recording regime of both flight time and crush scores. Selection based on the measures of temperament described in this study could be used to improve temperament itself and correlated improvements can also occur in meat tenderness and eating quality traits in tropically adapted breeds of cattle.
 

 

Sutherst R. W., A. S. Bourne, G. F. Maywald, G. W. Seifert. 2006. "Prevalence, severity, and heritability of Stephanofilaria lesions on cattle in central and southern Queensland, Australia". Australian Journal of Agricultural Research, 57(7): 743–750.

KEYWORDS: heritability, Stephanofilaria lesions, cattle

SUMMARY: Observations of cattle in central and southern Queensland are collated to define the prevalence and area of Stephanofilaria lesions associated with infestations of the buffalo fly, Haematobia irritans exigua. The observations were made on herds that were being used for other purposes. In a survey of ~1500 animals at Belmont in central Queensland in 1982, 98% of cows and 70% of calves had lesions. Most lesions were on the neck and dewlap and 10% were raw and weeping at the time of sampling. The total area of lesions per animal was strongly related to cattle breed and age. Old Bos taurus animals had the greatest area of lesions, whereas young Bos indicus had the least. Heritability estimates were low, averaging 0.01 for calves and 0.18 for cows. A smaller survey of cows and steers at Craighoyle in central Queensland in 1986 showed a higher numbers of lesions and positive correlations between the total lesion area and animal size. The lesion area increased with tick survival, suggesting that tick-resistant animals are also resistant to Stephanofilaria infection. Steers had smaller areas of lesions than cows, as found previously with cattle ticks. Long-term monitoring observations in central and southern Queensland between 1981 and 1986 showed that the total area of lesions was seasonal with a peak in late summer, consistent with the seasonal incidence of buffalo fly. Animals segregated into Low and High lesion herds maintained their differences over time. The lesions penetrated the dermis of the cattle hides and rendered the affected area unusable, but few lesions occurred on valuable parts of the hide so such economic effects are likely to be insignificant. One animal nearly died of a haemorrhage from a lesion on the dewlap and had to be treated. The results can inform policy on buffalo fly control, and biosecurity preparations in relation to the potential establishment of the Old World screw-worm fly, Chrysomyia bezziana, in Australia, which will be facilitated by the lesions. The results emphasise the significant animal welfare and biosecurity risks posed by the lesions in northern Australia.
 

 

Graham J. F., E. Bernaud, M. P. B. Deland. 2006. "Sire and dam breed effects on fatty acid profiles in the longissimus dorsi muscle and subcutaneous fat of beef cattle". Australian Journal of Experimental Agriculture, 46(7): 913–919.

KEYWORDS: breed, cattle, fatty acids, intramuscular fat, subcutaneous fat.

SUMMARY: This study investigated the effect of sire and dam breed on the fatty acid profiles of muscle and subcutaneous fat in beef cattle. Seven hundred and ninety-three steer and 222 female progeny derived from mating Angus and Hereford cows to Angus, Hereford, Limousin and Simmental bulls, were slaughtered at around 2 years of age (about 540 kg liveweight). The mean fat content of the longissimus dorsi muscle ranged from 4.6% for the Limousin-sired cattle to 6.0% for the Angus-sired cattle. Breed differences occurred in the majority of fatty acids from the intramuscular fat, but fewer differences were observed from the subcutaneous fat. The Limousin- and Simmental-sired progeny had less (P<0.001) saturated fat and more (P<0.001) unsaturated intramuscular fat compared with the Angus- and Hereford-sired cattle. The Angus and Simmental cattle had more (P<0.001) monounsaturates than the Limousin and Hereford cattle. There were differences (P<0.001) in the level of intramuscular polyunsaturates between all 4 sire-breeds, the Limousin having the highest and Angus the lowest. Simmental progeny had significantly higher levels of polyunsaturated fatty acids, compared with the Hereford-sired progeny, as well as a higher monousaturated : saturated fatty acid ratio. Hereford-sired progeny had a lower (P<0.001) monousaturated : saturated fatty acid ratio in the intramuscular fat. Intramuscular fatty acids were affected by dam breed, with progeny of Hereford cows having a higher percentage of unsaturated fatty acids (P = 0.015), lower saturated fatty acids (P = 0.011), and a higher monousaturated : saturated fatty acid ratio (P = 0.028) than those of Angus cows. There was no effect of dam breed on the totals of the different fatty acid groups in the subcutaneous fat. The subcutaneous fat had higher levels of saturated fatty acids and lower levels of unsaturated and polyunsaturated fatty acids compared with the intramuscular fat. Although the differences reported were generally small, it would seem that there may be scope to utilise these genetic differences to produce meat with more desirable fatty acid characteristics.
 

 

Zatoń-Dobrowolska Magdalena, Jindrich Čitek, Andrzej Filistowicz, Vaclav Řehout, Tadeusz Szulc. 2006. "An estimation of the genetic distance between Polish red and other red cattle breeds on the basis of selected milk protein loci". Electronic Journal of Polish Agricultural Universities, Animal Husbandry, Volume 9, Issue 2. Available Online:
http://www.ejpau.media.pl/volume9/issue2/art-10.html


KEYWORDS: genetic distance, polymorphism, red cattle.
SUMMARY: The material for the study were six populations of Red Cattle, including three samples of the Polish Red cattle population (PC’69, n = 203, PC’82, n = 261 and PC’96, n = 313) and one each of the Danish Red (DC, n = 169), German Red (NC, n = 510) and Czech Red (CC, n = 14). DNA was isolated from blood, according to the method by Gemmell and Akiyama (1996). All individuals were genotyping for the following proteins: αS1-casein, β-casein, κ-casein and β-lactoglobulin. The frequency of alleles was estimate and was used for the estimation of the genetic distance between populations. Using the PHYLIP ver. 3.5c software the genetic distance was determined according to 1) Nei, 2) Cavali-Sforza and 3) Reynolds. All the populations demonstrated a similar distribution of allele frequencies at individual loci. Only the Czech Red showed different tendencies as regards β- and κ-casein and β-lactoglobulin. This may have been the effect of the smaller population size as compared to the remaining breeds. Genetic distances estimated by these three using methods were similar. The smallest genetic distance was observed between populations PC’96 and NC (0.0007). In turn, the highest value was obtained between population DC and CC (0.0776). In the case of the genetic distance calculated according to the formulas by Cavalli-Sforza and Reynolds, the values obtained were higher then value of genetic distance estimated by Nei. The comparatively low values for the genetic distance obtained in the present studies may indicate that the breeds analysed originate from a common ancestor or lived on neighbouring geographical regions, what could lead to a frequent exchange of genes. The considerable similarity between those breeds could also be caused by a similarly conducted selection, based on similar assumptions (similar type of production). Those populations demonstrate similar gene pools what may be used for common preserve breeding programmes, which would decrease the danger of inbreeding. An analysis of the data collected over 30 years for the three populations of the Polish Red cattle, renders it possible to conclude that the frequency of individual alleles of the proteins examined are subjected to a small but continuous change.
 

 

Vozzi, Pedro Alejandro, Marcondes, Cíntia Righetti, Magnabosco, Cláudio De Ulhôa. 2006. "Structure and genetic variability in Nellore (Bos indicus) cattle by pedigree analysis". Genetic and Molecular Biology, 29: 482-485.

KEYWORDS: genetic drift; genetic variability matings; Nellore; pedigree analysis; probability of gene origin.

SUMMARY: Parameters based on the probability of gene origin were used to describe the genetic variability in strains of Nellore and polled Nellore (Bos indicus) cattle that participated in the Program for Genetic Improvement of the Nellore Breed (Programa de Melhoramento Genético da Raça Nelore). The effective number of founders was 87.2 for Nellore and 107.9 for polled Nellore, while the number of ancestors was 59.8 for Nellore and 61.5 for polled Nellore and the remaining genomes were 39.4 for Nellore and 34.5 for polled Nellore cattle. The results indicate an intense use (by artificial insemination) of some sires and the absence of subdivisions in the population. The family structure in the two breeds was mainly caused by the genetic contribution of the same sires and only mating preferences for descendants of some founders are recorded in either breed. The results suggest that genetic variability needs monitoring in order to avoid the compromise of genetic improvement in economically important traits in the breeding program.
 

 

Cervini, Marcelo, Henrique-Silva, Flávio, Mortari, Norma. 2006. "Genetic variability of 10 microsatellite markers in the characterization of Brazilian Nellore cattle (Bos indicus)". Genetic and Molecular Biology, 29: 486-490.

KEYWORDS: alleles; frequencies; microsatellite; Nellore; polymorphism; zebu.

SUMMARY: We assessed the polymorphism of 10 microsatellites in Brazilian Nellore cattle (Bos indicus) using a commercial multiplex system. Allele frequencies, polymorphism information content, heterozygosity and exclusion probability were calculated. Allele frequencies revealed that in the sample analyzed the markers were not equally polymorphic. The exclusion probabilities and the polymorphism information content of some loci in Nellore cattle were lower than in Bos taurus breeds. When all the microsatellites were considered the combined exclusion probability was 0.9989. This multiplex analysis can contribute toward pedigree information, adequate genetic improvements and breeding programs.
 

 

Rincon, Gonzalo, Armstrong, Eileen and Postiglioni, Alicia. 2006. "Analysis of the population structure of Uruguayan Creole cattle as inferred from milk major gene polymorphisms". Genetic and Molecular Biology, 29: 491-495.

KEYWORDS: DGAT1 gene; milk protein; SNPs; Uruguayan Creole cattle.

SUMMARY: The ancestors of Uruguayan Creole cattle were introduced by the Spanish conquerors in the XVII century, following which the population grew extensively and became semi-feral before the introduction of selected breeds. Today the Uruguayan Creole cattle genetic reserve consists of 575 animals. We used the tetra primer amplification refractory mutation system polymerase chain reaction (ARMS-PCR) to analyze the β-casein, κ-casein, αS1-casein and β-lactoalbumin gene polymorphisms and restriction fragment length polymorphism PCR (RFLP-PCR) for the -lactoglobulin and the acylCoA:diacyl glycerol acyltransferase 1 (DGAT1) genes.
b The β -casein and β -lactoglobulin genes presented very similar A and B allele -lactoalbumin gene B alleles showed muchafrequencies, while the αs1-casein and  higher frequencies than the corresponding A alleles. The β-casein B allele was not found in the population sampled. There was a very high frequency of the DGAT1 gene A allele which is associated with low milk fat content and high milk yield. All loci were in Hardy-Weinberg equilibrium and the level of heterozygosity agreed with the high genetic diversity observed in a previous analysis of this population. Preservation of the allelic richness observed in the Uruguayan Creole cattle should be considered for future dairy management and livestock genetic improvement. The results also emphasize the value of the tetra primers ARMS-PCR technique as a rapid, easy and economical way of genotyping cattle breeds for milk gene single nucleotide polymorphisms.
 

 

Sifuentes-Rincon, Ana M., Puentes-Montiel, Herlinda E., Moreno-Medina, Víctor R. 2006. "Assessment of the myostatin Q204X allele using an allelic discrimination assay". Genetic and Molecular Biology, 29: 496-497.

KEYWORDS: cattle; Charolais; carcass marker; allelic form; SNP detection.

SUMMARY: An allelic discrimination assay was designed and used to determine the genotypic and allelic frequencies of the myostatin (MSTN) gene Q204X allele from two Mexican Full-French herds. The assay is a simple high throughput genotyping method that could be applied to investigate the effect of the Q204X allele on the Charolais breed.
 

 

Vazquez-Flores, Felicitas, Alonso, Rogelio, Villegas-Sepulveda, Nicolás. 2006. "A microsatellite study of bovine solute carrier family 11 a1 (Slc11a1) gene diversity in Mexico in relation to bovine tuberculosis". Genetic and Molecular Biology, 29: 503-507.

KEYWORDS: bovine lineages; Mycobacterium bovis; microsatellite loci; Nramp1; Slc11a1; 3' UTR.

SUMMARY: Bovine tuberculosis, caused by Mycobacterium bovis, is a disease of socio-economic and public health importance and of significance to international trade regulation. Allelic variants of several genes have been implicated in the genetic susceptibility to tuberculosis in some human populations, but little is known in cattle. We surveyed 34 European, 18 Asian, 20 Creole and 23 hybrid bovines for polymorphisms of the bovine solute carrier family 11 a1(Slc11a1) gene, formerly known as natural resistance associated macrophage protein (Nramp1), gene by typing the cattle using two microsatellite loci closely linked to this gene. The microsatellites used were 311-22, located at the 3' untranslated region (3' UTR) of the Slc11a1 gene, and ARO28 situated about 0.6 cM upstream of the same gene Based on allele size in base pairs (bp) we determined five 311-223 locus variants (221, 223, 225, 227 and 229 bp) and 12 ARO28 loci. There was marked diversity and a very high level of heterozygosity in most of the cattle surveyed except the Europeans bovines and especially Holsteins in relation to the 3' UTR microsatellite locus.
 

 

Mehar S. Khatkar, Peter C. Thomson, Imke Tammen, Julie A.L. Cavanagh, Frank W. Nicholas, Herman W. Raadsma. 2006. "Linkage disequilibrium on chromosome 6 in Australian Holstein-Friesian cattle". Genetic Selection Evolution, 38: 463-477

KEYWORDS: linkage disequilibrium, dairy cattle, markers, chromosome 6

SUMMARY: We analysed linkage disequilibrium (LD) in Australian Holstein-Friesian cattle by genotyping a sample of 45 bulls for 15 closely-spaced microsatellites on two regions of BTA6 reported to carry important QTL for dairy traits. The order and distance of markers were based on the USDA-MARC linkage map. Frequencies of haplotypes were estimated using the E-M approach and a more computationally-intensive Bayesian approach as implemented in PHASE. LD was then estimated using the Hedrick multiallelic extension of Lewontin normalised coefficient . Estimates of from the two approaches were in close agreement (r = 0.91). The mean estimates of for marker pairs with an inter-marker distance of less than 5 cM (n = 13) are 0.57 and 0.51, and for distances more than 20 cM (n = 44) are 0.29 and 0.17, estimated from the E-M and Bayesian approaches, respectively. The Malecot model was fitted for the exponential decline of LD with map distance between markers. The swept radii (the distance at which LD has declined to 1/e ( 37%) of its initial value) are 11.6 and 13.7 cM for the above two methods, respectively. The Malecot model was also fitted using map distance in Mb from the bovine integrated map (bovine location database, bLDB) in addition to cM from the MARC map. Overall, the results indicate a high level of LD on chromosome 6 in Australian dairy cattle.
 

 

Wood Ian A., Gerhard Moser, Daniel L. Burrell, Kerrie L. Mengersen, D. Jay S. Hetzel. 2006. "A meta-analytic assessment of a Thyroglobulin marker for marbling in beef cattle". Genetic Selection Evolution, 38: 479-494.

KEYWORDS: Bayesian hierarchical model, meta-analysis, association studies, TG5 marker, beef marbling

SUMMARY: A meta-analysis was undertaken reporting on the association between a polymorphism in the Thyroglobulin gene (TG5) and marbling in beef cattle. A Bayesian hierarchical model was adopted, with alternative representations assessed through sensitivity analysis. Based on the overall posterior means and posterior probabilities, there is substantial support for an additive association between the TG5 marker and marbling. The marker effect was also assessed across various breed groups, with each group displaying a high probability of positive association between the T allele and marbling. The WinBUGS program code used to simulate the model is included as an Appendix available online at www.edpsciences.org/gse.
 

 

Xin Cai, Hong Chen, Shan Wang, Kai Xue, Chuzhao Lei. 2006. "Polymorphisms of two Y chromosome microsatellites in Chinese cattle". Genetic Selection Evolution, 38: 525-534.

KEYWORDS: Chinese cattle, taurine, indicine, genetic introgression, Y chromosome.

SUMMARY: Two Y chromosome specific microsatellites UMN2404 and UMN0103 were genotyped and assessed for polymorphisms in a total of 423 unrelated males from 25 indigenous Chinese cattle breeds. Consistently, both microsatellites displayed specific indicine and taurine alleles in each bull examined. The indicine and taurine alleles were detected in 248 males (58.6%), and 175 males (41.4%), respectively, although these frequencies varied amongst different breeds examined. The indicine alleles dominated in the southern group (92.4%), while the taurine alleles dominated in the northern group (95.5%). Hainan Island was possibly the site for the origin of Chinese zebu, and Tibetan cattle were probably independently domesticated from another strain of Bos primigenius. The geographical distribution of these frequencies reveals a pattern of male indicine introgression and a hybrid zone of indicine and taurine cattle in China. The declining south-to-north and east-to-west gradient of male indicine introgression in China could be explained by historical data, geographical segregation and temperature and weather conditions.
 

 

MacEachern Sean, John McEwan, Andrew Mather, Alan McCulloch, Paul Sunnucks, Mike Goddard. 2006. "Testing the neutral theory of molecular evolution using genomic data: a comparison of the human and bovine transcriptome". Genetic Selection Evolution, 38: 321-341.

KEYWORDS: adaptive evolution, Bos taurus, Homo sapiens, mammary gland, tissue specific genes

SUMMARY: Despite growing evidence of rapid evolution in protein coding genes, the contribution of positive selection to intra- and interspecific differences in protein coding regions of the genome is unclear. We attempted to see if genes coding for secreted proteins and genes with narrow expression, specifically those preferentially expressed in the mammary gland, have diverged at a faster rate between domestic cattle (Bos taurus) and humans (Homo sapiens) than other genes and whether positive selection is responsible. Using a large data set, we identified groups of genes based on secretion and expression patterns and compared them for the rate of nonsynonymous (dN) and synonymous (dS) substitutions per site and the number of radical (Dr) and conservative (Dc) amino acid substitutions. We found evidence of rapid evolution in genes with narrow expression, especially for those expressed in the liver and mammary gland and for genes coding for secreted proteins. We compared common human polymorphism data with human-cattle divergence and found that genes with high evolutionary rates in human-cattle divergence also had a large number of common human polymorphisms. This argues against positive selection causing rapid divergence in these groups of genes. In most cases dN/dS ratios were lower in human-cattle divergence than in common human polymorphism presumably due to differences in the effectiveness of purifying selection between long-term divergence and short-term polymorphism.
 

 

Khatkar Mehar S., Andrew Collins, Julie A. L. Cavanagh, Rachel J. Hawken, Matthew Hobbs, Kyall R. Zenger, Wes Barris, Alexander E. McClintock, Peter C. Thomson, Frank W. Nicholas and Herman W. Raadsma. 2006. "A First-Generation Metric Linkage Disequilibrium Map of Bovine Chromosome 6". Genetics, 174: 79-85

KEYWORDS: Linkage Disequilibrium, Bovine Chromosome 6

SUMMARY: We constructed a metric linkage disequilibrium (LD) map of bovine chromosome 6 (BTA6) on the basis of data from 220 SNPs genotyped on 433 Australian dairy bulls. This metric LD map has distances in LD units (LDUs) that are analogous to centimorgans in linkage maps. The LD map of BTA6 has a total length of 8.9 LDUs. Within the LD map, regions of high LD (represented as blocks) and regions of low LD (steps) are observed, when plotted against the integrated map in kilobases. At the most stringent block definition, namely a set of loci with zero LDU increase over the span of these markers, BTA6 comprises 40 blocks, accounting for 41% of the chromosome. At a slightly lower stringency of block definition (a set of loci covering a maximum of 0.2 LDUs on the LD map), up to 81% of BTA6 is spanned by 46 blocks and with 13 steps that are likely to reflect recombination hot spots. The mean swept radius (the distance over which LD is likely to be useful for mapping) is 13.3 Mb, confirming extensive LD in Holstein–Friesian dairy cattle, which makes such populations ideal for whole-genome association studies.
 

 

Viitala Sirja, Joanna Szyda, Sarah Blott, Nina Schulman, Martin Lidauer, Asko Mäki-Tanila, Michel Georges, Johanna Vilkki. 2006. "The Role of the Bovine Growth Hormone Receptor and Prolactin Receptor Genes in Milk, Fat and Protein Production in Finnish Ayrshire Dairy Cattle". Genetics, 173: 2151-2164

KEYWORDS: Bovine Growth Hormone Receptor, Prolactin Receptor, Genes, Milk, Fat, Protein, Ayrshire

SUMMARY: We herein report new evidence that the QTL effect on chromosome 20 in Finnish Ayrshire can be explained by variation in two distinct genes, growth hormone receptor (GHR) and prolactin receptor (PRLR). In a previous study in Holstein–Friesian dairy cattle an F279Y polymorphism in the transmembrane domain of GHR was found to be associated with an effect on milk yield and composition. The result of our multimarker regression analysis suggests that in Finnish Ayrshire two QTL segregate on the chromosomal region including GHR and PRLR. By sequencing the coding sequences of GHR and PRLR and the sequence of three GHR promoters from the pooled samples of individuals of known QTL genotype, we identified two substitutions that were associated with milk production traits: the previously reported F-to-Y substitution in the transmembrane domain of GHR and an S-to-N substitution in the signal peptide of PRLR. The results provide strong evidence that the effect of PRLR S18N polymorphism is distinct from the GHR F279Y effect. In particular, the GHR F279Y has the highest influence on protein percentage and fat percentage while PRLR S18N markedly influences protein and fat yield. Furthermore, an interaction between the two loci is suggested.
 

 

Freeman Abigail R., Clive J. Hoggart, O. Hanotte, Daniel G. Bradley. 2006. "Assessing the Relative Ages of Admixture in the Bovine Hybrid Zones of Africa and the Near East Using X Chromosome Haplotype Mosaicism". Genetics, 173: 1503-1510

KEYWORDS: Relative Ages, Admixture, Bovine Hybrid Zones, Africa, Near East, X Chromosome Haplotype Mosaicism

SUMMARY: Historical hybridization events between the two subspecies of cattle, Bos taurus and B. indicus, have occurred in several regions of the world, while other populations have remained nonadmixed. We typed closely linked X chromosome microsatellites in cattle populations with differing histories of admixture from Africa, Europe, the Near East, and India. Haplotype breakdown will occur as admixed populations age, and longer ancestral haplotypes will remain intact in more recently admixed populations compared to older ones. We genotyped male animals from these populations, obtaining unambiguous haplotypes, and measured levels of linkage disequilibrium (LD) and ancestral mosaicism. Extensive LD, likely to be the result of ongoing admixture, was discovered in hybrid cattle populations from the perimeter of the tsetse zone in West Africa. A Bayesian method to assign microsatellite allele ancestry was used to designate the likely origin of each chromosomal segment and assess the relative ages of admixture in the populations. A gradient of the age of admixture in the African continent emerged, where older admixture has produced more fragmented haplotypes in the south, and longer intact haplotypes, indicating more recent hybridization, feature in the northwest.

 

 

Sandor Cynthia, Frédéric Farnir, Sarah Hansoul, Wouter Coppieters, Théo Meuwissen, Michel Georges. 2006. "Linkage Disequilibrium on the Bovine X Chromosome: Characterization and Use in Quantitative Trait Locus Mapping". Genetics, 173: 1777-1786,

KEYWORDS: Linkage Disequilibrium, Bovine X Chromosome

SUMMARY: We herein demonstrate that in the Holstein–Friesian dairy cattle population, microsatellites are as polymorphic on the X chromosome as on the autosomes but that the level of linkage disequilibrium between these markers is higher on the X chromosome than on the autosomes. The latter observation is not compatible with the small male-to-female ratio that prevails in this population and results in a higher gonosomal than autosomal effective population size. It suggests that the X chromosome undergoes distinct selective or mutational forces. We describe and characterize a novel Markovian approach to exploit this linkage disequilibrium to compute the probability that two chromosomes are identical-by-descent conditional on flanking marker data. We use the ensuing probabilities in a restricted maximum-likelihood approach to search for quantitative trait loci (QTL) affecting 48 traits of importance to the dairy industry and provide evidence for the presence of QTL affecting 5 of these traits on the bovine X chromosome.
 

 

Wang Z., J. D. Nkrumah, C. Li, J. A. Basarab, L. A. Goonewardene, E. K. Okine, D. H. Crews, Jr., S. S. Moore. 2006. "Test duration for growth, feed intake, and feed efficiency in beef cattle using the GrowSafe System". Journal of Animal Science, 84:2289-2298.

KEYWORDS: beef cattle, feed efficiency, repeated measures analysis, test duration

SUMMARY: This study was conducted to determine the optimum test duration and the effect of missing data on accuracy of measuring feed efficiency and its 4 related traits ADG, DMI, feed conversion ratio, and residual feed intake in beef cattle using data from 456 steers with 5,397 weekly averaged feed intakes and BW repeated measurements taken over 91 d. Data were collected using the GrowSafe System at the University of Alberta Kinsella Research Station. The changes and relative changes in phenotypic residual variances and correlations (Pearson and Spearman) among data from shortened test durations (7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, or 84 d) and a 91-d test were used to determine the optimum test duration for the 4 traits. The traits were fitted to a mixed model with repeated measures using SAS. Test durations for ADG, DMI, feed conversion ratio, and residual feed intake could be shortened to 63, 35, 42, and 63 d, respectively, without significantly reducing the accuracy of the tests when BW was measured weekly. The accuracy of the test was not compromised when up to 30% of the records were randomly removed after the first 35 d on test. These results have valuable and practical implications for performance and feed efficiency testing in beef cattle.
 

 

Davis M. E., R. C. M. Simmen. 2006. "Genetic parameter estimates for serum insulin-like growth factor I concentrations, and body weight and weight gains in Angus beef cattle divergently selected for serum insulin-like growth factor I concentration". Journal of Animal Science, 84:2299-2308.

KEYWORDS: beef cattle, genetic parameter, growth, insulin-like growth factor, selection

SUMMARY: Data for the current study were obtained from a divergent selection experiment in which the selection criterion was the average serum IGF-I concentrations of 3 postweaning blood samples collected from purebred Angus calves. Multiple-trait derivative-free REML procedures were used to obtain genetic parameter estimates for IGF-I concentrations and for BW and BW gains measured from birth to the conclusion of a 140-d postweaning performance test. Included in the analysis were 2,674 animals in the A–1 matrix, 1,761 of which had valid records for IGF-I concentrations. Direct heritability estimates ± SE for IGF-I concentration at d 28, 42, and 56 of the postweaning period and for mean IGF-I concentrations were 0.44 ± 0.07, 0.51 ± 0.08, 0.42 ± 0.07, and 0.52 ± 0.08, respectively. Heritability estimates for maternal genetic effects ranged from 0.10 ± 0.05 to 0.20 ± 0.06. The proportion of total phenotypic variance due to the maternal permanent environmental effect was essentially zero for all measures of IGF-I concentrations. Genetic correlations of IGF-I concentrations with weaning and post-weaning BW ranged from 0.07 ± 0.12 to 0.32 ± 0.11 and generally demonstrated an increasing trend during the postweaning period. Averaged across the various measures of IGF-I, the genetic correlation of IGF-I with preweaning gain was 0.14, whereas the genetic correlation with postweaning gain was 0.29. Genetic correlations between IGF-I and BW gain were positive during all time intervals, except between weaning and the beginning of the postweaning test and from d 84 to 112 of the postweaning period. Environmental and phenotypic correlations of IGF-I with BW and BW gains were generally positive, but small. These results indicate that postweaning serum IGF-I concentration is moderately to highly heritable and has small positive genetic, environmental, and phenotypic correlations with BW other than birth weight and with pre- and postweaning gain. Therefore, if IGF-I proves to be a biological indicator of an economically important trait (e.g., efficiency of feed use for growth) in beef cattle, it should be possible to rapidly change IGF-I concentrations via selection without significantly altering live weight or rate of gain.
 

 

Snowder G. D., L. D. Van Vleck, L. V. Cundiff, G. L. Bennett. 2006. "Bovine respiratory disease in feedlot cattle: Environmental, genetic, and economic factors". Journal of Animal Science, 84: 1999-2008.

KEYWORDS: beef cattle, breed, disease resistance, growth, heritability, shipping fever

SUMMARY: The objective of this study was to characterize genetic, environmental, and economic factors related to the incidence of bovine respiratory disease (BRD) in feedlot calves. Records from 18,112 calves representing 9 breeds (Angus, Braunvieh, Charolais, Gelbvieh, Hereford, Limousin, Pinzgauer, Red Poll, and Simmental) and 3 composite types (MARC I, MARC II, and MARC III) over a 15-yr period (1987 to 2001) were evaluated. Disease incidence was observed and recorded by station veterinary and technical staff. The incidence of BRD varied across years, with the annual observed incidence ranging from 5 to 44%. From 1987 to 1992, the annual average incidence generally exceeded 20%. However, in later years the annual incidence did not exceed 14%. The epidemiological pattern indicated that BRD infection increased dramatically after 5 d on feed and remained high until approximately 80 d on feed. Previous BRD infection during the preweaning period did not influence subsequent BRD infection in the feedlot. Steers were more likely to become sick with BRD than heifers; castration before entry in the feedlot may be a predisposing cause. Few significant differences among breeds were detected for BRD incidence. Adjusted solutions from mixed model analyses indicated that Herefords were generally more susceptible to BRD infection (P < 0.05) than MARC I and III composite types. Composite breed types had similar susceptibility compared with other purebred breeds. Mortality associated with BRD was greatest in Red Poll calves (9%) compared with the average over all breeds (4%). Estimates of heritability for resistance to BRD ranged from 0.04 to 0.08 ± 0.01. When the observed heritability was transformed to an underlying continuous scale, the estimate increased to 0.18. Selection for resistance to BRD could be effective if phenotypes for BRD resistance were known. Thus, development of an inexpensive and humane method of challenging animals with BRD to determine resistance would be an important step in reducing the incidence of BRD. This study also demonstrated that producer-collected field data could be used for selection against this disease. The economic loss associated with lower gains and treatment costs for BRD infection in a 1,000-cattle feedlot was estimated as $13.90 per animal, not including labor and associated handling costs.
 

 

Bormann J. Minick, L. R. Totir, S. D. Kachman, R. L. Fernando, D. E. Wilson. 2006. "Pregnancy rate and first-service conception rate in Angus heifers". Journal of Animal Science, 84:2022-2025.

KEYWORDS: beef cattle, fertility, genetics, pregnancy

SUMMARY: The objective of this project was to determine the genetic control of conception rate, or pregnancy percentage in Angus beef heifers. Producers from 6 herds in 5 states provided 3,144 heifer records that included breeding dates, breeding contemporary groups, service sires, and pregnancy check information. Two hundred fourteen sires of the heifers were represented; with 104 sires having less than 5 progeny, and 14 sires having greater than 50 progeny. These data were combined with performance and pedigree information, including actual and adjusted birth weights, weaning weights, and yearling weights, from the American Angus Association database. Heifer pregnancy rate varied from 75 to 95% between herds, and from 65 to 100% between sires, with an overall pregnancy rate of 93%, measured as the percentage of heifers pregnant at pregnancy check after the breeding season. Pregnancy was analyzed as a threshold trait with an underlying continuous distribution. A generalized linear animal model, using a relationship matrix, was fitted. This model included the fixed effects of contemporary group, age of dam, and first AI service sire, and the covariates of heifer age at the beginning of breeding, adjusted birth weight, adjusted weaning weight, and adjusted yearling weight. The relationship matrix included 4 generations of pedigree. The heritability of pregnancy and first-service conception rates on the underlying scale was 0.13 ± 0.07 and 0.03 ± 0.03, respectively. Estimated breeding values for pregnancy rate on the observed scale ranged from –0.02 to 0.05 for sires of heifers. Including growth traits with pregnancy rate as 2-trait analyses did not change the heritability of pregnancy rate. As expected for a reproductive trait, the heritability of pregnancy rate was low. Because of its low heritability, genetic improvement in fertility by selection on heifer pregnancy rate would be expected to be slow.
 

 

MacNeil M. D., T. B. Mott. 2006. "Genetic analysis of gain from birth to weaning, milk production, and udder conformation in Line 1 Hereford cattle". Journal of Animal Science, 84:1639-1645.

KEYWORDS: genetic correlation, growth, heritability, maternal, udder score
SUMMRY: The objective of this research was to partition phenotypic variation in calf gain from birth to weaning, and milk production measured, by the weigh-suckle-weigh method, and udder score of cows into genetic and nongenetic components. Data were from the Line 1 Hereford population maintained by USDA-ARS at Miles City, MT, and included observations of pre-weaning gain (n = 6,835) from 2,172 dams, milk production (n = 692) from 403 cows, and udder score (n = 1,686) from 622 cows. Data were analyzed using a Gibbs sampler for multiple-trait animal models. Results are reported as means ± SD derived from the posterior distributions of parameter estimates. Mean estimates of the phenotypic variance of preweaning gain, milk production, and udder score were 476.3 kg2, 8.88 kg2, and 1.89 (1 to 9 scale), respectively. Estimates of phenotypic correlations between preweaning gain and milk production, preweaning gain and udder score, and milk production and udder score were 0.37 ± 0.04, – 0.07 ± 0.04, and – 0.09 ± 0.05, respectively. Estimates of heritability for direct and maternal preweaning gain, milk production, and udder score were 0.13 ± 0.03, 0.25 ± 0.04, 0.25 ± 0.06, and 0.23 ± 0.05, respectively. Genetic correlations of milk production with maternal preweaning gain and udder score were estimated as 0.80 ± 0.08 and – 0.36 ± 0.16, respectively. Posterior distributions of the other genetic correlations all contained 0.00 within the respective 90% probability density posterior intervals. Estimates of repeatability of maternal preweaning gain, milk production, and udder score were 0.43 ± 0.03, 0.39 ± 0.05, and 0.34 ± 0.03, respectively. Breeding value for maternal gain from birth to weaning was highly predictive of breeding value for milk production. Direct measurement of milk production to use in genetic improvement may not be justified because it is difficult to measure, and selection based on the breeding value for maternal preweaning gain may be nearly as effective in changing milk production as direct selection. A potentially undesirable consequence of selection to increase milk production is the degradation of udder quality. However, this correlation is not so strong as to preclude simultaneous improvement of milk production and udder quality using appropriate predicted breeding values for each trait.
 

 

MacNeil M. D., T. W. Geary, G. A. Perry, A. J. Roberts, L. J. Alexander. 2006. "Genetic partitioning of variation in ovulatory follicle size and probability of pregnancy in beef cattle". Journal of Animal Science, 84:1646-1650.

KEYWORDS: cattle, fertility, follicle, ovulation

SUMMARY: The objectives of this research were to partition variation in ovulatory follicle size into genetic and nongenetic components and to assess the utility of ovulatory follicle size as an indicator trait associated with reproductive success in beef cattle. Data were collected during the years 2002 to 2005 from 780 beef females that ranged in age from 1 to 12 yr (mean of 2.4 observations per female). Data were analyzed with a multiple trait Gibbs sampler for animal models to make Bayesian inferences from flat priors. A chain of 500,000 Gibbs samples was thinned to every 200th sample to produce a posterior distribution composed of 2,500 samples. Heritability estimates (posterior mean ± SD) were 0.16 ± 0.03 for follicle size and 0.07 ± 0.02 and 0.02 ± 0.01 for pregnancy rate as a trait of the female and service sire, respectively. Posterior means of genetic correlations were all <0.10, with 0.00 contained within the respective 90% probability density posterior intervals. Results indicate that whereas follicle size is of greater heritability than pregnancy rate, its usefulness to improve reproductive rate is greatest as an ancillary phenotype in multiple trait selection.
 

 

Casellas J., J. Tarrés, J. Piedrafita, L. Varona. 2006. "Parametric bootstrap for testing model fitting in the proportional hazards framework: An application to the survival analysis of Bruna dels Pirineus beef calves". Journal of Animal Science, 84:2609-2616.

KEYWORDS: model fitting, parametric bootstrap, proportional hazard, survival analysis

SUMMARY: Given that correct assumptions on the baseline survival function are determinant for the validity of further inferences, specific tools to test the fit of a model to real data become essential in proportional hazards models. In this sense, we have proposed a parametric bootstrap to test the fit of survival models. Monte Carlo simulations are used to generate new data sets from the estimates obtained through the assumed models, and then bootstrap intervals can be established for the survival function along the time space studied. Significant fitting deficiencies are revealed when the real survival function is not included within the bootstrap interval. We tested this procedure in a survival data set of Bruna dels Pirineus beef calves, assuming 4 parametric models (exponential, Weibull, exponential time-dependent, Weibull time-dependent) and the Cox’s semiparametric model. Fitting deficiencies were not observed for the Cox’s model and the exponential time-dependent model, whereas the Weibull time-dependent model suffered from moderate overestimation at different ages. Thus, the exponential time-dependent model appears to be preferable because of its correct fit for survival data of beef calves and its smaller computational and time requirements. Exponential and Weibull models were completely rejected due to the continuous over- and underestimation of the survival probability reported. Results here highlighted the flexibility of parametric models with time-dependent effects, achieving a fit comparable to nonparametric models.
 

 

Shojo M., T. Okanishi, K. Anada, K. Oyama, F. Mukai. 2006. "Genetic analysis of calf market weight and carcass traits in Japanese Black cattle". Journal of Animal Science, 84: 2617-2622.

KEYWORDS: beef cattle, direct genetic effect, genetic correlation, genetic variance, heritability, maternal effect

SUMMARY: Heritabilities of and genetic correlations between additive direct and maternal genetic effects for calf market weight, and additive direct genetic effects for carcass traits, were estimated for Japanese Black cattle by REML procedures under 2-trait animal models. Data were collected from calf and carcass markets in Hyogo and Tottori prefectures and analyzed separately by prefecture. Calf market weight was measured on 42,745 and 23,566 calves in Hyogo and Tottori, respectively. Only the fattening animals with calf market weight were extracted from the carcass database and used for estimation. The carcass traits analyzed were carcass weight, ribeye area, rib thickness, subcutaneous fat thickness, yield estimate, beef marbling score, and 4 meat characters (color, brightness, firmness, and texture). Direct and maternal heritabilities for calf market weight were estimated to be 0.22 and 0.07 in Hyogo, and 0.37 and 0.15 in Tottori, respectively. The estimates of heritabilities for carcass traits were moderate to high in both prefectures. The estimates of direct-maternal genetic correlations for calf market weight were positive (0.17) in Hyogo and negative (–0.63) in Tottori. The direct effect for calf market weight was positively correlated with the direct effect for carcass weight (0.87 and 0.56 in Hyogo and Tottori, respectively) but negatively correlated with the direct effect for beef marbling score (–0.10 in both prefectures). The estimates of genetic correlations between the maternal effect for calf market weight and the direct effects for carcass traits varied from –0.13 to 0.34 in Hyogo and from –0.14 to 0.15 in Tottori. Because direct and maternal genetic effects for early growth traits can be evaluated from calf market weight data in the production system of Japanese Black cattle, this information should be incorporated into selection and mating schemes of the breed.
 

 

VanRaden P. M., R. H. Miller. 2006. "Effects of Nonadditive Genetic Interactions, Inbreeding, and Recessive Defects on Embryo and Fetal Loss by Seventy Days". Journal of Dairy Science, 89:2716-2721

KEYWORDS: nonreturn rate, recessive defect, inbreeding, dominance

SUMMARY: Lethal recessive genes that cause early embryo loss are difficult to detect. Nonreturn rate at 70 d after first insemination (NR) was evaluated as a trait of the embryo using 1,739,055 first-service records from 1,251 Holstein bulls represented as both service sires and sires of cows. Effects modeled included herd-year-season, parity of cow, sire of cow, service bull, interaction of service bull with sire of cow, and regression on inbreeding of embryo. Variances of service bull and sire of cow were estimated using REML and estimated effects were removed from the data. Interaction variance was estimated from the residuals using the tilde-hat approximation to REML. An additive relationship matrix was used for sire of cow and a dominance relationship matrix for the interaction term. Service bull effects were assumed constant across time and unrelated. For each 10% increase in inbreeding, NR percentage declined by an estimated 1%. A regression of this size could be explained by > 20% of animals carrying defects that cause early embryo loss. Of the total variance, service bull contributed 0.36%; sire of cow, 0.24% (heritability of 1.0%); and interaction, 0.18% (dominance variance of 2.8%). Numbers of records exceeded 500 for 50 bull pair subclasses. Predicted interactions that included effects of inbreeding ranged from – 3.6% to +2.9%, compared with the mean NR of 56%. The largest negative interactions were not caused by known recessive defects. Complex vertebral malformation generally causes loss of pregnancies later in gestation, and few current bulls carry the gene for deficiency of uridine monophosphate synthase. Further study of the families with largest negative interactions could uncover new recessive defects.
 

 

Cole J. B., P. M. VanRaden. 2006. " Genetic Evaluation and Best Prediction of Lactation Persistency". Journal of Dairy Science, 89:2722-2728

KEYWORDS: best prediction, genetic evaluation, persistency

SUMMARY: Cows with high persistency tend to produce less milk than expected at the beginning of lactation and more than expected at the end. Best prediction of persistency was calculated as a function of a trait-specific standard lactation curve and a linear regression of test-day deviations on days in milk. Regression coefficients were deviations from a balance point to make yield and persistency phenotypically uncorrelated. The objectives of this study were to calculate (co)variance components and breeding values for best predictions of persistency of milk (PM), fat (PF), protein (PP), and SCS (PSCS) in Holstein cows. Data included 8,682,138 lactations from 4,375,938 cows calving since 1997, and 39,354 sires were evaluated. Sire estimated breeding values (EBV) for PM, PF, and PP were similar and ranged from –0.70 to 0.75 for PM; EBV for PSCS ranged from –0.37 to 0.28. Regressions of sire EBV on birth year were near zero (<0.003) but positive for PM, PF, and PP, and negative for PSCS. Genetic correlations of PM, PF, and PP with PSCS were moderate and favorable, indicating that increasing SCS decreases yield traits, as expected. Genetic correlations among yield and persistency were low to moderate and ranged from –0.09 (PSCS) to 0.18 (PF). This definition of persistency may be more useful than those used in test-day models, which are often correlated with yield. Routine genetic evaluations for persistency are feasible and may allow for improved predictions of yield traits. As calving intervals increase, persistency may have greater value.
 

 

Nauta W. J., R. F. Veerkamp, E. W. Brascamp, H. Bovenhuis. 2006. "Genotype by Environment Interaction for Milk Production Traits Between Organic and Conventional Dairy Cattle Production in The Netherlands". Journal of Dairy Science, 89: 2729-2737.

KEYWORDS: genotype by environment interaction, organic dairy production, somatic cell score

SUMMARY: Estimates of genetic parameters for organic dairy farming have not been published previously, and neither is information available on the magnitude of genotype by environment interaction (GxE) between organic and conventional farming. However, organic farming is growing worldwide and basic information about genetic parameters is needed for future breeding strategies for organic dairy farming. The goal of this study was to estimate heritabilities of milk production traits under organic farming conditions and to estimate the magnitude of GxE between organic and conventional dairy farming. For this purpose, production records of first-parity Holstein heifers were used. Heritabilities of milk, fat and protein yield, and somatic cell score (SCS) were higher under organic farming conditions. For percentages of fat and protein, heritabilities of organic and conventional production were very similar. Genetic correlations between preorganic and organic, and organic and conventional milk production were 0.79 and 0.80, respectively. For fat yield, these correlations were 0.86 and 0.88, and for protein yield, these were 0.78 and 0.71, respectively. Our findings indicate that moderate GxE was present for yield traits. For percentage of fat and protein and SCS, genetic correlations between organic and conventional and preorganic production were close to unity, indicating that there was no GxE for these traits.
 

 

Weller J. I., E. Ezra, G. Leitner. 2006. "Genetic Analysis of Persistency in the Israeli Holstein Population by the Multitrait Animal Model". Journal of Dairy Science, 89: 2738-2746

KEYWORDS: persistency, multitrait animal model, Israeli Holstein, genetic evaluation

SUMMARY: Persistency was defined as the predicted milk production 180 d after peak divided by peak production (in %). Heritability of persistency in a multitrait analysis including parities 1 through 5 increased from 0.16 to 0.27 from first through third parity, and then declined through fifth parity. Genetic correlations for persistency between consecutive parities were all > 0.8. First-parity genetic correlations of the traits included in the Israeli selection index with persistency were all < 0.1, except for fertility and herdlife, which were 0.20 and 0.25; whereas second-parity genetic correlations of persistency with the 3 milk production traits were all > 0.34, and the genetic correlation with fertility was only 0.10. The genetic correlation between second-parity persistency and herdlife was 0.58. Persistency in the Israeli Holstein population was analyzed by the multitrait animal model. The genetic trend since 1985 for the multiparity index was 0.22% persistency/yr, even though there was no direct selection on persistency.
 

 

Maltecca C., H. Khatib, V. R. Schutzkus, P. C. Hoffman and K. A. Weigel. 2006. "Changes in Conception Rate, Calving Performance, and Calf Health and Survival From the Use of Crossbred Jersey x Holstein Sires as Mates for Holstein Dams". Journal of Dairy Science, 89:2747-2754

KEYWORDS: crossbreeding, dairy calf, health, immune function

SUMMARY: Differences in conception rates in matings of Holstein sires or F1 Jersey x Holstein sires to Holstein dams in the University of Wisconsin–Madison experimental herd were evaluated, as were differences in birth weight, dystocia, serum protein, serum IgG, fecal consistency, respiratory disease, and perinatal and pre-weaning mortality among the resulting calves. When mated to randomly chosen, lactating Holstein cows, Holstein sires (n = 74) and crossbred sires (n = 7) did not differ in male fertility. Calves from Holstein sires and multiparous Holstein dams (n = 99) were 1.9 kg heavier than calves from crossbred sires and multiparous Holstein dams (n = 211), leading to greater likelihood (odds ratio of 1.24) of dystocia. Furthermore, calves from crossbred sires and multiparous Holstein dams had higher serum protein and serum IgG levels between 24 and 72 h of age, as well as lower rates of perinatal and preweaning morality than calves from Holstein sires and multiparous or primiparous Holstein dams. Mean fecal consistency scores from birth to 7 d of age and number of days with scours also tended to be lower among calves from crossbred sires, compared with calves from Holstein sires. No differences were observed in the incidence or severity of respiratory disease. Results of this study suggest that introduction of Jersey genes via crossbreeding may lead to a reduction in dystocia and improvements in calf health and survival in Holstein herds. Future studies should address other traits related to dairy farm profitability, including milk composition, female fertility, longevity, feed efficiency, and resistance to infectious and metabolic diseases.
 

 

Cienfuegos-Rivas E. G., R. W. Blake, P. A. Oltenacu, H. Castillo-Juarez. 2006. "Fertility Responses of Mexican Holstein Cows to US Sire Selection". Journal of Dairy Science, 89:2755-2760

KEYWORDS: genotype by environment interaction, milk yield, age at first calving, Mexico

SUMMARY: Genetic relationships between 2 fertility traits and milk production were investigated using mature-equivalent lactation records of 55,162 daughters of 1,339 Holstein sires in Mexico and 499,401 daughters of 663 Holstein sires in the northeastern United States. Data sets contained yields in first and second lactation, age at first calving (AFC), and calving interval (CI). There were 474 US sires in common between countries. A herd-year standard deviation criterion defined nonoverlapping low- ( 1,300 kg) and high- ( 1,600 kg) opportunity Mexican herd environments and a low-opportunity ( 1,024 kg) US environment. Genetic variances for the average Mexican herd (all data) for AFC and CI were 65 and 85% as large as those obtained from half-sisters in the average US herd. Genetic correlations for first-lactation milk in the average US herd and AFC and CI in the average Mexican environment were unfavorable (0.18 and 0.10). Regression coefficients of AFC in Mexican environments on US genetic gain in milk ranged from 2 to 7 d/1,000 kg. However, the favorable predicted response in AFC from genetic gain in milk in Mexican environments, like those in average US herds, ranged from – 4 to – 7 d/1,000 kg (rg = – 0.20). This unequal AFC response may indicate genotype by environment interaction in fitness performance or differential breeding management of high and low yielding Mexican cows. The potential effects of age at first service of breeding females need to be disentangled to accurately assess genetic improvement needs for Mexican Holstein herds.
 

 

Gengler N., G. R. Wiggans, L. L. M. Thornton, J. R. Wright, T. Druet. 2006. "Accounting for Heterogeneous Variances in Multitrait Evaluation of Jersey Type Traits". Journal of Dairy Science, 89:3143-3151

KEYWORDS: heterogeneous variance adjustment, type evaluation
SUMMAARY: The multitrait genetic evaluation system for type traits was modified to estimate adjustments for heterogeneous variance (HV) simultaneously with estimated breeding values (EBV) for final score and 14 linear traits. Each variance within herd, year, and parity was regressed toward a predicted variance, which was determined by fitting a model with fixed effects of the mean final score for herd, size of the contemporary group, appraisal month, and year-season and a random effect for herd-appraisal date. Herd-appraisal date was included as a random effect to regress the observed heterogeneity for a given herd-appraisal date toward the fixed effects. Method R was used to estimate variances for the heterogeneity model in each EBV iteration. To evaluate the effect of the adjustment, parent averages were calculated from evaluations with recent appraisals removed. The adjustment slightly improved correlations within birth year between those parent averages and EBV from current data on bulls for most traits, but did not improve correlations for final score, strength, dairy form, teat length, or foot angle. Annual trends for EBV were lower with HV adjustment than for unadjusted EBV for all traits except final score and rump angle for cows and rump width for bulls, which were essentially unchanged. Standard deviations of Mendelian sampling (evaluation minus mean of parent evaluations) declined less over time for HV-adjusted than for unadjusted evaluations. The slope at year 2000 of Mendelian-sampling standard deviations from HV-adjusted evaluations ranged from 10.0% for udder depth to 42.7% for teat length compared with the slope for unadjusted evaluations. This HV adjustment, which was implemented for USDA evaluations in May 2001 for Jerseys and in 2002 for other breeds, improves the accuracy of evaluations, particularly comparisons over time, by accounting for the change in variation.
 

 

Strabel T., J. Jamrozik. 2006. "Genetic Analysis of Milk Production Traits of Polish Black and White Cattle Using Large-Scale Random Regression Test-Day Models". Journal of Dairy Science, 89:3152-3163

KEYWORDS: dairy cattle, test-day yield, persistency, random regression model

SUMMARY: Genetic parameters for milk, fat, and protein yield and persistency in the first 3 lactations of Polish Black and White cattle were estimated. A multiple-lactation model was applied with random herd-test-day effect, fixed regressions for herd-year and age-season of calving, and random regressions for the additive genetic and permanent environmental effects. Three data sets with slightly different edits on minimal number of days in milk and the size of herd-year class were used. Each subset included more than 0.5 million test-day records and more than 58,000 cows. Estimates of covariance components and genetic parameters for each trait were obtained by Bayesian methods using the Gibbs sampler. Due to the large size and a good structure of the data, no differences in estimates were found when additional criteria for record selection were applied. More than 95% of the genetic variance for all traits and lactations was explained by the first 2 principal components, which were associated with the mean yield and lactation persistency. Heritabilities of 305-d milk yield in the first 3 lactations (0.18, 0.16, 0.17) were lower than those for fat (0.12, 0.11, 0.12) and protein (0.13, 0.14, 0.15). Estimates of daily heritabilities increased in general with days in milk for all traits and lactations, with no apparent abnormalities at the beginning or end of lactation. Genetic correlations between yields in different lactations ranged from 0.74 (fat yield in lactations 1 and 3) to 0.89 (milk yield in lactations 2 and 3). Persistency of lactation was defined as the linear regression coefficient of the lactation curve. Heritability of persistency increased with lactation number for all traits and genetic correlations between persistency in different lactations were smaller than those for 305d yield. Persistency was not genetically correlated with the total yield in lactation.
 

 

Sanders K., J. Bennewitz, N. Reinsch, G. Thaller, E.-M. Prinzenberg, C. Kühn, E. Kalm. 2006. "Characterization of the DGAT1 Mutations and the CSN1S1 Promoter in the German Angeln Dairy Cattle Population". Journal of Dairy Science, 89:3164-3174

KEYWORDS: DGAT1, casein promoter, dairy cattle

SUMMARY: The identification of quantitative trait loci (QTL) and genes with influence on milk production traits has been the objective of various mapping studies in the last decade. In the centromeric region of Bos taurus autosome (BTA) 14, the acyl-CoA:diacylglycerol acyltransferase1 gene (DGAT1) has been identified as the most likely causative gene underlying a QTL for milk fat yield and content. Recently, a second polymorphism in the promoter of DGAT1 emerged as an additional source of variation. In this study, the frequencies and the effects of alleles at the DGAT1 K232A and at the DGAT1 promoter variable number of tandem repeat (VNTR) locus on BTA14, and of alleles at the CSN1S1 ( S1-casein–encoding gene) promoter on BTA6 in the German Angeln dairy cattle population were investigated. Analyzed traits were milk, fat, protein, lactose, and milk energy yield, fat, protein, lactose, and milk energy content and somatic cell score. The lysine variant of the DGAT1 K232A mutation showed significant effects for most of the milk production traits. A specific allele of the DGAT1 promoter VNTR showed significant effects on the traits lactose yield and content, milk energy content, and SCS compared with the other alleles. Additionally, a regulation mechanism between the DGAT1 K232A mutation and the DGAT1 promoter VNTR was found for fat yield and content, which could be caused by an upper physiological bound for the effects of the DGAT1 gene. At the CSN1S1 promoter, 2 of 4 alleles showed significant allele substitution effects on the milk yield traits.
 

 

Longeri M., M. Polli, M. G. Strillacci, A. B. Samorè, M. Zanotti. 2006. "Short Communication: Quantitative Trait Loci Affecting the Somatic Cell Score on Chromosomes 4 and 26 in Italian Holstein Cattle". Journal of Dairy Science, 89:3175-3177

KEYWORDS: somatic cell score, quantitative trait loci, microsatellite

SUMMARY: This work aimed to confirm previously reported quantitative trait loci (QTL) affecting the somatic cell score (SCS) in dairy cattle on Bos taurus autosomes (BTA) 4 and 26. A granddaughter design with selective genotyping was implemented that included half-sib families from 12 male lines of Italian Holstein cattle. The animals were genotyped for 5 microsatellite markers each on regions of BTA 4 (average marker spacing 9.42 cM) and BTA 26 (average marker spacing 5.26 cM), previously reported by other authors as carrying QTL for somatic cell count. Quantitative trait loci analyses were performed using interval mapping by regressing sire breeding values for SCS onto genotype probabilities at 1-cM intervals along the 2 chromosome regions. Breeding values for SCS were estimated for the whole population using a test-day repeatability animal model. Results were not significant on a chromosome basis, but a possible QTL was found at BM4505 on BTA 26, confirming this region for further studies of QTL affecting SCS in the Italian Holstein population.
 

 

Macciotta N. P. P., D. Vicario, A. Cappio-Borlino. 2006. "Use of Multivariate Analysis to Extract Latent Variables Related to Level of Production and Lactation Persistency in Dairy Cattle". Journal of Dairy Science, 89: 3188-3194

KEYWORDS: lactation curve, lactation persistency, factor analysis, principal component analysis

SUMMARY: Multivariate factor analysis and principal component analysis were used to decompose the correlation matrix of test-day milk yields of 48,374 lactations of 21,721 Italian Simmental cows. Two common latent factors related to level of production in early lactation and lactation persistency, and 2 principal components associated with the whole lactation yield and persistency were obtained. Factor and principal component scores were treated as new quantitative phenotypes related to prominent features of lactation curve shape. Genetic parameters were estimated by univariate and bivariate animal models. Estimates of heritability were moderately low for both latent factors (0.13 for persistency and yield early in lactation). Heritabilities of the principal component related to total lactation yield and 305-d yield were similar (0.19 and 0.20, respectively). Finally, heritability was quite low for the principal component related to lactation persistency (0.07). Repeatabilities between lactations were about 0.27 for both latent factors, around 0.4 for the first principal component and 305-d yield, and 0.11 for the second principal component. Moderate genetic correlation among common factors (0.26) and their high genetic correlation with total lactation yield (>0.60) suggest that selection can be used to change the shape of lactation curve as well as improve yield. Scores of the second principal component can be used to genetically improve persistency while maintaining constant total lactation yield.

 

 

Harder B., J. Bennewitz, D. Hinrichs, E. Kalm. 2006. "Genetic Parameters for Health Traits and Their Relationship to Different Persistency Traits in German Holstein Dairy Cattle". Journal of Dairy Science, 89:3202-3212

KEYWORDS: dairy cattle, disease liability, persistency

SUMMARY: Data from 3,200 Holstein cows from 3 commercial dairy farms in Germany were used to estimate heritabilities and breeding values for liability to udder diseases (UD), fertility diseases (FD), metabolic diseases (MD), and claw and leg diseases (CLD) using single-trait threshold sire models. A total of 92,722 medical treatments recorded from 1998 to 2003 were included in the analysis. Approximate genetic correlations between persistency of milk yield, fat yield, protein yield, and persistency of milk energy yield and liability to the health traits were calculated based on correlations between EBV. Posterior means of heritability of liability ranged from 0.05 to 0.08 for UD, from 0.04 to 0.07 for FD, from 0.08 to 0.12 for MD, and from 0.04 to 0.07 for CLD. Approximate genetic correlations of the disease traits with the persistency traits were favorable, except for MD in all lactations, which were unfavorable, and UD, which were around zero. Highest correlations in the range of 0.13 to 0.46 were found between the different persistency traits and CLD.
 

 

VanRaden P. M., C. M. B. Dematawewa, R. E. Pearson, M. E. Tooker. 2006. "Productive Life Including All Lactations and Longer Lactations with Diminishing Credits". Journal of Dairy Science, 89:3213-3220

KEYWORDS: longevity, productive life, lactation length

SUMMARY: Alternative measures of productive life (PL) were compared, and life expectancy factors were updated to replace estimates from 1993. Alternatives were proposed with extra credits for lactations longer than 10 mo and beyond 84 mo of age and for each calving so that an extremely long lactation would not receive more credits than multiple shorter lactations with dry periods between. Maximum credits per lactation of 10 mo (original PL), 12 mo, and unlimited were compared. The unlimited credits option either included or excluded a calf value equal to 2 mo of production and had credits given for all days either uniformly or based on lactation curves (diminishing credits). Standard lactation curves (first, second, and greater lactations) were estimated based on the test-day yields of Holstein cows remaining in lactation from a set of 903,579 lactation records. For the diminishing credits alternative, credit for a given day of a parity was derived using the predicted yield of the day proportional to the average daily yield of the first 305 d of second parity. Daily yields were deviations from a baseline of 13.62 kg. Heritabilities and genetic correlations were estimated by multitrait REML for alternative measures of PL, for longevity censored at various ages, and for yield traits and SCS in first parity. Data for REML analysis included records from 1,098,329 Holsteins born from 1994 through 1997 from 5,109 sires, and a relationship matrix among sires was included in the model. Lactations beyond 84 mo added little information. Heritability of PL was 0.073 with 10 mo, 0.069 with 12 mo, 0.068 and 0.067 with unlimited (uniform) lactation credits (with and without calf credits, respectively), and 0.070 with unlimited diminishing credits. Corresponding correlations among predicted transmitting abilities for PL and protein yield were 0.07, 0.06, 0.12, 0.23, and 0.09, all much lower than the 0.46 estimated in 1993. Heritability of PL with diminishing credits improved from 0.017 to 0.070 when censoring age increased from 36 to 96 mo. There was no further increase in heritability beyond 96 mo. Genetic correlation with the final PL was 0.87 when PL was censored at 36 mo, but the estimate increased steadily with the censoring age. The PL with diminishing credits, which was favorable in both economic and genetic aspects, was desirable in crediting cows for complete lactations.
 

 

Sewalem A., F. Miglior, G. J. Kistemaker, B. J. Van Doormaal. 2006. "Analysis of the Relationship Between Somatic Cell Score and Functional Longevity in Canadian Dairy Cattle". Journal of Dairy Science, 89:3609-3614

KEYWORDS: functional longevity, somatic cell score, Canadian dairy breed

SUMMARY: The aim of this study was to assess the level of somatic cell count (SCC) and to explore the impact of somatic cell score (SCS) on the functional longevity of Canadian dairy cattle by using a Weibull proportional hazards model. Data consisted of 1,911,428 cows from 15,970 herds sired by 7,826 sires for Holsteins, 80,977 cows in 2,036 herds from 1,153 sires for Ayrshires, and 53,114 cows in 1,372 herds from 1,758 sires for Jerseys. Functional longevity was defined as the number of days from the first calving to culling, death, or censoring. The test-day SCC was transformed to a linear score, and the resulting SCS were averaged within each lactation. The average SCS were grouped into 10 classes. The statistical model included the effects of stage of lactation; season of production; annual change in herd size; type of milk recording supervision; age at first calving; effects of milk, fat, and protein yields, calculated as within-herd-year-parity deviations; herd-year-season of calving; SCS class; and sire. The relative culling rate was calculated for animals in each SCS class after accounting for the aforementioned effects. The overall average SCC for Holsteins was 167,000 cells/mL, for Ayrshires was 155,000 cells/mL, and for the Jerseys was 212,000 cells/mL. In all breeds there were no appreciable differences in the relative risk of culling among classes of SCS breed averages (i.e., up to a SCS of 5). However, as the SCS increased beyond the breed average, the relative risk of cows being culled increased considerably. For instance, Holstein, Ayrshire, and Jersey cows with the highest classes of SCS had, respectively, a 4.95, 6.73, and 6.62 times greater risk of being culled than cows with average SCS.

 

 

Nielsen H. M., L. G. Christensen, J. Ødegård. 2006. "A Method to Define Breeding Goals for Sustainable Dairy Cattle Production". Journal of Dairy Science, 89:3615-3625

KEYWORDS: breeding objective. desired gain index, sustainability

SUMMARY: The objective of this study was to present a method to define breeding goals for sustainable dairy cattle production by adding nonmarket values to market economic values for functional traits in the breeding goal. A nonmarket value can represent the value of improved animal welfare or societal influences for animal production. The nonmarket value for mastitis resistance, conception rate, and stillbirth were derived based on how much farmers or breeding companies were willing to lose in selection response for milk yield to improve functional traits. The desired response for milk yield corresponding to a given percent loss was obtained using desired gain indices. By allowing a 5% loss in the selection response for milk yield, the nonmarket value was found to be 40.4 for mastitis resistance, 16.1 for conception rate, and –9.7 for stillbirth. The nonmarket value increased proportionally with increasing loss in the selection response for milk yield, but the selection response was lower for conception rate than for mastitis resistance because of differences in market economic value and heritability. To increase the response for conception rate, the nonmarket value was also derived for 2 situations, in which the desired responses for milk yield, mastitis resistance, and conception rate were specified. The method can be used to define breeding goals for sustainable production and to increase the response for traits that are at critically low levels. When defining breeding goals for sustainable production, breeding organizations should predict the selection response based on market economic value and add non-market value for traits with unacceptable selection responses.
 

 

Sharma B. S., I. Leyva, F. Schenkel, N. A. Karrow. 2006. "Association of Toll-Like Receptor 4 Polymorphisms with Somatic Cell Score and Lactation Persistency in Holstein Bulls". Journal of Dairy Science, 89:3626-3635

KEYWORDS: Toll-like receptor 4, health trait, somatic cell score, Canadian Holstein

SUMMARY: Mastitis, an inflammatory disease of the mammary gland generally caused by intramammary infections, is the most frequently occurring disease in the North American dairy industry. Reduced milk yield, milk quality, and lactation persistency as well as early culling contribute to the economic losses associated with this disease. During intramammary infections, cells of the innate immune system become activated through pattern recognition receptors that recognize conserved molecular signatures associated with the invading pathogen. The quality, timing, and intensity of the host inflammatory and subsequent immune response determine the fate of this disease. Toll-like receptor 4 (TLR4) is an important pattern recognition receptor that recognizes endotoxins associated with gram-negative bacterial infections. Its role in pathogen recognition and subsequent initiation of the inflammatory and immune response makes it a suitable candidate gene for enhancing disease resistance in Canadian Holsteins. In this study, polymorphisms in the TLR4 gene were identified in the Canadian Holstein bull population. Genotypes and haplotypes were constructed, and their associations with somatic cell score and lactation persistency were determined. Sequencing of selective DNA pools was used to reveal polymorphisms in TLR4. Two DNA pools were constituted based on high and low estimated breeding values for somatic cell scores. A total of 3 single nucleotide polymorphisms (SNP), including 1 SNP in a putative promoter region (P-226) and 2 SNP in exon3 (E3+1656 and E3+2021) of TLR4 were detected. A total of 388 bulls were genotyped for the SNP, haplotypes were reconstructed, and their frequencies were obtained. Polymorphisms in these regions were found to be associated with estimated breeding values for lactation persistency, and somatic cell scores in the Canadian Holstein bull population. The unfavorable alleles at P-226 and E3+1656 were found at a frequency of 40 and 37%, respectively; hence, selection against these alleles is promising in Canadian Holsteins. Selection against the unfavorable allele, T at E3+2021, is limited because of its low frequency (7%). Two frequently occurring haplotypes (GCC and CTC) occurred in 86% of the Canadian Holstein bull population chosen for genotyping. The most frequent haplotype (GCC; 54%) was found to be associated with higher lactation persistency and lower somatic cell scores. The transversion SNP in the putative promoter region (P-226) was in a potential DNA binding site.
 

König S., F. Köhn, K. Kuwan, H. Simianer, M. Gauly. 2006. "Use of Repeated Measures Analysis for Evaluation of Genetic Background of Dairy Cattle Behavior in Automatic Milking Systems". Journal of Dairy Science, 89:3636-3644

KEYWORDS: automatic milking system, milking frequency, heritability, genetic correlation

SUMMARY: Milking frequencies measured at official test days were used with repeated measurement analysis to reveal the environmental and genetic impact on the milking frequency of cows in automatic milking systems. Repeated measurements were 3 test-day observations per cow within days in milk (DIM) classes, with 1,216 cows in DIM class 1 (d 0 to 99), from 1,112 cows in DIM class 2 (d 100 to 199), and from 1,004 cows in DIM class 3 (d 200 to 299) kept in 15 farms. Selection criteria for models analyzing repeated measurements were Akaike and Schwarz Bayesian values, which favored the autoregressive [AR(1)] covariance structure over the compound symmetry model. Results from the AR(1) model indicated a significant impact of fixed herd and parity effects. Milking frequencies decreased with increasing parities and were greatest for first-parity cows. High daily milk yield was associated with higher milking frequencies. Heritabilities for milking frequency were 0.16, 0.19, and 0.22 in DIM classes 1, 2, and 3, respectively, from the AR(1) model. Higher heritabilities in the later stage of lactation were due to a substantial reduction of the residual variance. Genetic correlations between test-day milk yield and daily milking frequency were in the range of 0.46 to 0.57 for all DIM classes and between milking frequency and somatic cell score were near zero. For verification of results, milking frequencies of the same cows obtained from herd management programs were averaged within DIM classes. Heritabilities were slightly above the values from the AR(1) model. In conclusion, heritabilities for milking frequency in automatic milking systems are moderate enough to incorporate this behavioral trait in a combined breeding goal. The inevitable improvement of labor efficiency in dairy cattle farming demands such cows going easily and voluntarily in automatic milking systems.
(16-Oct-2006)
 

Løvendahl P., M. A. Bjerring. 2006. "Detection of Carryover in Automated Milk Sampling Equipment". Journal of Dairy Science, 89:3645-3652
KEYWORDS: carryover, milk sampling, milk recording

SUMMARY: Equipment for sampling milk in automated milking systems may cause carryover problems if residues from one sample remain and are mixed with the subsequent sample. The degree of carryover can be estimated statistically by linear regression models. This study applied various regression analyses to several real and simulated data sets. The statistical power for detecting carryover milk improved considerably when information about cow identity was included and a mixed model was applied. Carryover may affect variation between animals, including genetic variation, and thereby have an impact on management decisions and diagnostic tools based on the milk content of somatic cells. An extended procedure is needed for approval of sampling equipment for automated milking with acceptable latitudes of carryover, and this could include the regression approach taken in this study.
(16-Oct-2006)
 

Sharma B. S., G. B. Jansen, N. A. Karrow, D. Kelton, Z. Jiang. 2006. "Detection and Characterization of Amplified Fragment Length Polymorphism Markers for Clinical Mastitis in Canadian Holsteins". Journal of Dairy Science, 89:3653-3663

KEYWORDS: amplified fragment length polymorphism, clinical mastitis, quantitative trait locus mapping, radiation hybrid mapping

SUMMARY: Mastitis is the most frequent, complex, and costly disease in dairy cattle. Genetic improvement of milk production traits has accompanied an increased susceptibility to mastitis. To determine genome-wide quantitative trait locus-linked markers for mastitis resistance, a total of 200 cows, comprising 100 top clinical mastitis- (CM) resistant and 100 top CM-susceptible cows, were screened by selective DNA pooling and amplified fragment length polymorphism (AFLP) technique. The AFLP analysis on resistant and susceptible pools using 89 selective primer combinations revealed 27 significant AFLP markers at a false discovery rate (FDR) of <5%. The most promising AFLP marker was then selected for further characterization. Individual AFLP genotyping of the marker on all selected animals confirmed a significant difference. Sequence analysis detected a single nucleotide polymorphism (A G) responsible for the AFLP polymorphism, which was named CGIL4. The PCR-RFLP analysis indicated that the frequency of allele A was significantly higher in the resistant group. The logistic regression analysis demonstrated that the marker was significantly associated with somatic cell score, CM residual values, and production traits. Radiation hybrid mapping assigned the marker to Bos taurus autosome 22. The present study provides promising markers for marker-assisted selection for CM resistance. Our results also demonstrated the capability of AFLP on selective DNA pools as a method for detection of genome regions containing quantitative trait loci.
(16-Oct-2006)
 

Holmberg M., L. Andersson-Eklund. 2006. "Quantitative Trait Loci Affecting Fertility and Calving Traits in Swedish Dairy Cattle". Journal of Dairy Science, 89:3664-3671

KEYWORDS: quantitative trait loci, fertility, calving, dairy cattle

SUMMARY: Impaired fertility is the main reason for involuntary culling of dairy cows in Sweden. The objective of this study was to map quantitative trait loci (QTL) influencing fertility and calving traits in the Swedish dairy cattle population. The traits analyzed were number of inseminations, 56-d nonreturn rate, interval from calving to first insemination, fertility treatments, heat intensity score, stillbirth, and calving performance. A genome scan covering 20 bovine chromosomes was performed using 145 microsatellite markers. The mapping population consisted of 10 sires and their 417 sons in a granddaughter design. Nine of the sires were of the Swedish Red Breed, and one was a Swedish Holstein. Least squares regression was used to map loci affecting the analyzed traits, and permutation tests were used to set significance thresholds. Cofactors were used in the analyses of individual chromosomes to adjust for QTL found on other chromosomes. The use of cofactors increased both the number of QTL found and the significance level. In the initial analysis, we found 13 suggestive QTL that were mapped to chromosomes 6, 7, 9, 11, 13, 15, 20, and 29. When cofactors were included, 30 QTL were detected on chromosomes 1, 3, 4, 18, 19, 22, and 25, in addition to the 8 previously mentioned chromosomes. Some of the results from the cofactor analysis may be false positives and require further validation. In conclusion, we were able to map several QTL affecting fertility and calving traits in Swedish dairy cattle.
(16-Oct-2006)
 

Garcia-Peniche T. B., B. G. Cassell, I. Misztal. 2006. "Effects of Breed and Region on Longevity Traits Through Five Years of Age in Brown Swiss, Holstein, and Jersey Cows in the United States". Journal of Dairy Science, 89:3672-3680

KEYWORDS: breed comparison, region, survival

SUMMARY: The objective of this study was to assess breed, and breed x region interactions for several longevity-related traits, measured up to 5 yr of age in Brown Swiss, Holstein, and Jersey cows in 7 regions of the United States. Data were analyzed using logistic, poisson, and linear models, and survival analyses. The traits were stayability (yes/no survived to 5 yr of age), number of completed lactations, days lived, herd-life, and days in milk (DIM) to 5 yr of age. Probable lifetime DIM were also estimated using data from the first 5 yr of age of the cows. Herd-life was defined as the days lived up to 5 yr of age minus the age at first calving. Days in milk consisted of herd-life up to 5 yr of age minus the dry periods. Three data files were analyzed: herds with one breed of cows, herds with Holstein and Brown Swiss, and herds with Holstein and Jersey cows. Breed x region interaction was usually significant, with larger effects for the southern regions. Jerseys obtained largest values for the ratio of DIM to days lived, and for the number of completed lactations to 5 yr of age. Brown Swiss had the largest probabilities of surviving to 5 yr of age (stayabilities) in all regions. For the other traits, the results for Brown Swiss were inconsistent, but usually the cows of this breed had shorter herd-life and DIM to 5 yr of age than Holsteins. Brown Swiss cows were expected to have more total DIM in their lifetime in the Southeast than Holsteins. Survival analysis gave the most readily interpretable information, although the linear, poisson, and logistic analyses answered slightly different questions. Adjustment for herd size did not modify the results.
(16-Oct-2006)
 

Averill T., R. Rekaya, K. Weigel. 2006. "Random Regression Models for Male and Female Fertility Evaluation Using Longitudinal Binary Data". Journal of Dairy Science, 89:3681-3689

KEYWORDS: longitudinal binary data, random regression, fertility, dairy cow

SUMMARY: A longitudinal Bayesian threshold analysis of insemination outcomes was carried out using 2 random regression models with 3 (Model 1) and 5 (Model 2) parameters to model the additive genetic values at the liability scale. All insemination events of first-parity Holstein cows were used. The outcome of an insemination event was treated as a binary response of either a success (1) or a failure (0). Thus, all breeding information for a cow, including all service sires, was included, thereby allowing for a joint evaluation of male and female fertility. An edited data set of 369,353 insemination records from 210,373 first-lactation cows was used. On the liability scale, both models included the systematic effects of herd-year, month of insemination, technician, and regressions on age of service sire and milk yield during the first 100 d of lactation. The random effects in the model were the 3 or 5 random regression coefficients specific to each cow, the permanent effect of the cow, and the service sire effect. Using Model 1, the estimated heritability of an insemination outcome decreased from 0.035 at d 50 to 0.032 at d 140 and then increased continuously with DIM. The genetic correlations for insemination success at different time points ranged from 0.83 to 0.99, and their magnitude decreased with an increase in the interval between inseminations. A similar trend was observed for heritability and genetic correlations using Model 2. However, the average estimate of heritability was much higher (0.058) than those obtained using Model 1 or a repeatability model. In addition, the estimated genetic correlations followed the same trend as Model 1, but were lower and with a higher rate of decrease when the interval between inseminations increased. The posterior mean of service sire variance was 0.01 for both models, and permanent environmental variance was 0.05 and 0.02 for Models 1 and 2, respectively. Model comparison based on the Bayes factor indicated that Model 1 was more plausible, given the data.
(16-Oct-2006)
 

Heringstad B., Y. M. Chang, I. M. Andersen-Ranberg, D. Gianola. 2006. "Genetic Analysis of Number of Mastitis Cases and Number of Services to Conception Using a Censored Threshold Model". Journal of Dairy Science, 89:4042-4048

KEYWORDS: clinical mastitis, censoring, female fertility, threshold model

SUMMARY: The objective of this study was to infer genetic parameters and genetic change for number of clinical mastitis cases (NCM) and number of services to conception (STC) in first-lactation Norwegian Red (NRF) cows. Records on 620,492 daughters of 3,064 NRF sires, with first calving from 1980 through 2004, were analyzed with a bivariate threshold liability model that takes censoring into account. Posterior mean (SD) of heritability of liability was 0.08 (0.004) for NCM and 0.03 (0.002) for STC. The mean (SD) of the posterior distribution of the genetic correlation between the 2 traits was 0.21 (0.04). Posterior means of the correlation between herd-5-yr effects, and between residuals for NCM and STC were 0.17 and 0.05, respectively. To evaluate effects of taking censoring into account, the data were also analyzed with a bivariate ordered threshold model ignoring censoring. The genetic correlation between NCM and STC was lower than in the censored threshold model (0.09 vs. 0.21). Heritability of liability to NCM and STC from this model was also slightly lower, whereas the point estimates of herd-5-yr and residual correlations were 0.15, and –0.01, respectively. These results suggest that genetic (co)variance may be understated in models ignoring censoring. For comparison purposes, the data were analyzed with a bivariate linear sire model and standard REML-BLUP procedures. The correlation (rank correlation) between sire evaluations from the censored threshold model and sire predicted transmitting abilities from the linear model was 0.90 (0.90) for NCM and 0.87 (0.86) for STC. The evolution of average sire posterior means by birth year of daughters was used to assess genetic change, and results indicated genetic reduction (i.e., genetic improvement) of NCM and little or no genetic change for STC in the NRF population.
(16-Oct-2006)

Carlén E., U. Emanuelson, E. Strandberg. 2006. "Genetic Evaluation of Mastitis in Dairy Cattle Using Linear Models, Threshold Models, and Survival Analysis: A Simulation Study". Journal of Dairy Science, 89:4049-4057

KEYWORDS: genetic evaluation, mastitis, simulation, survival analysis

SUMMARY: The objective was to study, by simulation, whether survival analysis results in a more precise genetic evaluation for mastitis in dairy cattle than cross-sectional linear models and threshold models by using observation periods for mastitis of 2 lengths (the first 150 d of lactation, and the full lactation, respectively). True breeding values for mastitis liability on the underlying scale were simulated for daughters of 400 sires (average daughter group size, 60 or 150), and the possible event of a mastitis case within lactation for each cow was created. For the linear models and the threshold models, mastitis was defined as a binary trait within either the first 150 d of lactation or the full lactation. For the survival analysis, mastitis was defined as the number of days from calving to either the first case of mastitis (uncensored record) or to the day of censoring (i.e., day of culling, lactation d 150 or day of next calving; censored record). Cows could be culled early in lactation (within 10 d after calving) for calving-related reasons or later on because of infertility. The correlation between sire true breeding values for mastitis liability and sire predicted breeding values was greater when using the full lactation data (0.76) than when using data from the first 150 d (0.70) with an average of 150 daughters per sire. The corresponding results were 0.60 and 0.53, respectively, with an average of 60 daughters per sire. Under these simulated conditions, the method used had no effect on accuracy. The higher accuracy of sire breeding values can be translated into a greater genetic gain, unless counteracted by a longer generation interval.
(16-Oct-2006)
 

Terawaki Y., T. Katsumi, V. Ducrocq. 2006. "Development of a Survival Model with Piecewise Weibull Baselines for the Analysis of Length of Productive Life of Holstein Cows in Japan". Journal of Dairy Science, 89: 4058-4065

KEYWORDS: survival model, piecewise Weibull baseline, longevity, survival analysis

SUMMARY: A total of 100,000 records of Holstein dairy cows in Hokkaido, Japan, were used to study the current characteristics of their length of productive life, to build up a suitable model for genetic survival analysis, and to apply the piecewise Weibull baseline model. The data for this analysis only included records of cows belonging to herds in which more than 60% of cows had type score. Compared with other studies, the proportions of cows with only 1 or 2 calvings were low (24 and 46%, respectively), indicating a very low culling rate in first or second parity in Hokkaido. The median length of productive life was about 1,250 d (3 yr and 5 mo). Four different definitions of stages of lactation were studied. The best fit of the data was obtained when stages of lactation were chosen with cutpoints at 0, 60, 250, and 350 d after calving. Whatever the definition of stages of lactation, the piecewise Weibull baseline model was better than a unique baseline model. The estimated shape Weibull parameters for the different parity x stage of lactation combinations varied greatly (1.0 to 5.0). The estimated hazard functions based on the piecewise Weibull baseline model were smooth and reflected the important changes in observed hazard within lactation. The results of this study are expected to contribute to the development of a genetic model for sire evaluation and to genetic improvement of length of productive life of Holstein cattle in Hokkaido, Japan.
(16-Oct-2006)
 

De Ketelaere A., K. Goossens, L. Peelman, C. Burvenich. 2006. "Technical Note: Validation of Internal Control Genes for Gene Expression Analysis in Bovine Polymorphonuclear Leukocytes". Journal of Dairy Science, 89:4066-4069

KEYWORDS: gene expression analysis, control gene, bovine polymorphonuclear leukocyte

SUMMARY: Analysis of gene expression is becoming more important in all areas of biological research to evaluate gene expression during physiological and pathological conditions (e.g., mastitis), not the least in the field of animal research. Presently, real-time gene expression analysis is considered to be the method of choice for accurate and sensitive quantification of mRNA transcripts. Because comparison of gene expression levels is frequently the aim of these experiments, there is a critical need to validate internal control genes. When studying gene expression in bovine polymorphonuclear leukocytes, special attention should be paid to this validation, because polymorphonuclear leukocytes are subjected to numerous physiological influences, depending on the stage of lactation. In this study, 8 commonly used reference genes (ACT, GAPD, H2A, TBP, HPRT1, SDHA, YWHAZ, and 18S rRNA) were evaluated in bovine polymorphonuclear leukocytes. The transcription levels of 6 reference genes were determined using real-time PCR. By geometrically averaging the expression levels of these genes, SDHA, YWHAZ, and 18S rRNA were selected as being the most stable genes for accurate normalization of real-time results of bovine polymorphonuclear leukocytes.
(16-Oct-2006)
 

Druet T., S. Fritz, D. Boichard, J. J. Colleau. 2006. "Estimation of Genetic Parameters for Quantitative Trait Loci for Dairy Traits in the French Holstein Population". Journal of Dairy Science, 89:4070-4076

KEYWORDS: genetic parameter, quantitative trait locus, dairy trait, marker-assisted selection

SUMMARY: A marker-assisted selection program (MAS) has been implemented in dairy cattle in France. The efficiency of such a selection program depends on the use of correct genetic parameters for the marked quantitative trait loci (QTL). Therefore, the objective of this study was to estimate the proportion of genetic variance explained by 4 QTL described in previous studies (these QTL are segregating on chromosomes 6, 14, 20, and 26). Genotypes for 11 markers were available for 3,974 bulls grouped within 54 sire families of the French Holstein population undergoing MAS. The parameters were estimated for 4 QTL and 5 dairy traits: milk, fat and protein yields, and fat and protein percentages. The proportion of genetic variance explained by the QTL ranged from as low as 0.03 to 0.36%. Both lack of marker informativity and poor monitoring of QTL transmission might limit the accuracy of estimation. The QTL explained a larger proportion of genetic variance for milk composition traits. The QTL on chromosome 14 and chromosomes 6 and 20 have their largest influence on fat and protein percentages, respectively. The overall proportions of genetic variance explained by the QTL were 27.0, 30.7, 24.1, 48.2, and 33.6% for milk, fat and protein yields, and fat and protein percentages, respectively. These results clearly indicated that a large part of the genetic variance is explained by a small number of QTL and that their use in MAS might be beneficial for dairy cattle breeding programs.
(16-Oct-2006)
 

Sørensen A. C., P. Madsen, M. K. Sørensen, P. Berg. 2006. "Udder Health Shows Inbreeding Depression in Danish Holsteins". Journal of Dairy Science, 89:4077-4082

KEYWORDS: inbreeding depression, udder health, mastitis, somatic cell count

SUMMARY: The purpose of this study was to estimate inbreeding depression for udder health using records on mastitis incidence and somatic cell count (SCC). Data were selected based on a pedigree completeness index so that inbreeding coefficients were reliable. Average inbreeding was 3.3%. The presence or absence of mastitis was considered in first (CM1), second (CM2), and third (CM3) lactations, and was recorded as a binary trait. Somatic cell count was also included and analyzed on the log scale. A minimum of 140,000 cows with records were included per trait. Linear sire models were used and (co)variance components were estimated. Linear and curvilinear effects of the coefficient of inbreeding were included. Inbreeding significantly affected all traits investigated. Three traits, CM1, CM3, and SCC, showed a nonlinear relationship between phenotype and inbreeding coefficient. A cow with 5% inbreeding compared with a cow with 2% inbreeding had a higher SCC and a higher incidence of mastitis. The SCC increased by 1,500 cells/mL in first lactation and the incidence of mastitis increased by 1.08, 0.55, and 0.98% in first, second, and third lactation, respectively. The corresponding reduction in net return from these traits over 3 lactations amounted to US$11.00 under Danish production circumstances. These results are a step on the way to estimating the total cost of inbreeding depression to determine an acceptable rate of inbreeding.
(16-Oct-2006)

Abdullah A.R., Olutogun, O. 2006. "Estimates of genetic and phenotypic parameters for preweaning growth traits of N'Dama (Bos Taurus) calves in the humid tropics of Nigeria". Livestock Research for Rural Development. Volume 18, Article #120. Retrieved September 27, 2006, from:
http://www.cipav.org.co/lrrd/lrrd18/8/abdu18120.htm

KEYWORDS: Genetic and phenotypic parameters, humid tropics, N'Dama, Nigeria, preweaning growth traits

SUMMARY: Birth weight (BWT), 205-day adjusted weaning weight (205DWT) and average daily gain till weaning (ADG) data of 1277 N'Dama calves were analyzed by nested analysis of variance procedure of SAS to derive half-sib estimate of variance and covariance components which were used to estimate heritability and both genetic and phenotypic correlations between the pairs of traits. The repeatability estimates were also computed for the traits using records of 594 calves. The heritability estimates increased with age of calves from 0.10 ± 0.052 for BWT to 0.39 ± 0.09 for 205DWT. The genetic correlation ranged from 0.47 between ADG and BWT, 0.53 between BWT and 205DWT to 0.99 between BWT and ADG. Phenotypic correlations between the traits followed the same trend ranging from 0.15 between ADG and BWT, 0.58 between BWT and 205DWT to 0.99 between 205DWT and ADG. The repeatability estimate was 0.10 ± 0.004 for each of the three traits. The low estimates of all the genetic parameters in this study confirmed the effect of poor management and nutrition in limiting the expression of the true genetic worth of the indigenous stock.
(16-Oct-2006)
 

Koenig S., H. Simianer. 2006. "Approaches to the management of inbreeding and relationship in the German Holstein dairy cattle population". Livestock Science, 103 (1-2): 40-53

KEYWORDS: Dairy cattle; Inbreeding; Relationship; Optimum genetic contributions
SMMAARY: The aim of this study was to estimate the current level of inbreeding in the German cow population and for bull dams born in Germany, to find out sires most related to different subsets of their breed and to demonstrate the negative effect of homozygosity in the case of complex vertebral malformation (CVM). Further on, the application of optimum genetic contribution (OGC) theory for the selection of bull dams and bull sires in different breeding scenarios was investigated. Levels of inbreeding for the cow population were in a low range from 0.97% to 1.70% evaluating birth years from 1996 to 1999 in a total dataset of 244,427 registered Holstein cows. The inbreeding coefficient of 8030 bull dams was much higher, i.e. 3.71%, for the birth year 1999. Increases in inbreeding of 0.19% per year indicated an effective population size of only 52 animals. Individual sires like R.O.R.A. Elevation and Hannoverhill Starbuck were highly related to potential bull dams with coefficients of relationship of 13.4% and 12.9%, respectively, whereas P.F. Arlinda Chief (16.3%) and Carlin-M Ivanhoe Bell (16.1%) were highest related to the best available AI sires. Coefficients of relationship were calculated by classes of estimated breeding values (EBV) for production traits showing highest values above 7% in the two highest EBV-classes. The optimum genetic contribution theory using official EBVs and approximative, for zero inbreeding corrected EBVs, was applied for elite matings in a breeding program embracing 30 young bulls per year to find the optimal allocations of bull sires and bull dams. Compared with the actual breeding program applied in practice, OGC-theory has the potential to increase genetic gain under the same constraint for the increase of average relationship by 13.1%. A more relaxed constraint on increase in inbreeding allowed even higher expected genetic gain whereas a more severe constraint resulted in more equal contributions of selected bull sires. Contributions from 21 selected bull sires and 30 selected bull dams for a scenario at 5% constrained relationship were used to develop a specific mating plan to minimise inbreeding in the short term in the following generation applying a simulated annealing algorithm. The expected coefficient of inbreeding of progeny was 66.3% less then the one resulting from random mating. Mating programs can address inbreeding concerns on the farm, at least in the short term, but long-term control of inbreeding in a dairy population requires consideration of relationships between young bulls entering AI progeny test programs. Significantly better EBVs of CVM-free bulls compared with CVM-carriers for the paternal fertility justify the application of OGC for elite matings.
(16-Oct-2006)
 

Dooley A.E., W.J. Parker, H.T. Blair, N. Lopez-Villalobos. 2006. "Selection and segregation of herds for a valuable milk trait". Livestock Science, 102 (1-2): 60-71

KEYWORDS: Niche products; Milk segregation; Milk fat colour; Dairying; Animal breeding

SUMMARY: Dairy processors are seeking to exploit the natural variation in milk components at the farm level to produce high margin niche products. On-farm segregation of milk within or between herds and enhancement of desired traits are mechanisms to increase supply. A simulation modelling approach was used to investigate the genetic effects of breeding and segregating cows for an illustrative milk attribute, milk fat colour. This trait is valuable to New Zealand seasonal supply dairy farmers. Changes in production and the proportion of cows producing “white” (lighter milk fat colour) milk were predicted for a 20 year period for several selection strategies. Genetic gains relative to the status quo were predicted using sires from a small breeding scheme selecting for milk fat colour and yield. It took 18 years or more of continuous breeding for the whole herd to produce “white” milk, although not necessarily over the whole of the lactation under a pasture-based farming system. Selection on colour reduced yield of other valuable traits relative to the status quo herd. Initial selection of cows, reproduction and management strategies can all speed up progress but add cost. Premiums for segregated milks need to compensate owners for transition costs, production losses (if any) relative to the status quo, and the risk associated with long term change.
(16-Oct-2006)
 

Khatib Hasan, Valerie Schutzkus. 2006."The expression profile of the H19 gene in cattle". Mammalian Genome, 17 (9): 991-996

KEYWORDS: H19 gene, cattle

SUMMARY: The expression of the H19 gene has been well studied in fetal human and mouse tissues but not in cattle. It is generally believed that H19 is abundantly expressed in the early stages of embryogenesis and is repressed postnatally. We report the expression pattern of this gene in cattle in a total of 120 fetal-organ combinations and in a total of 108 adult-organ combinations using quantitative real time PCR. In fetal tissues, H19 was abundantly expressed in amnion, chorion, and allantois. Fetal liver, lung, heart, spleen, eye, rib, mammary gland, and cotyledon showed moderate expression, while intestine and brain showed lower expression levels. For some organs examined in this study, the expression pattern in cattle fetal organs was similar to that of human, mouse, and sheep. For adult organs, H19 was highly expressed in muscle and moderately expressed in liver, lung, heart, kidney, pancreas, and ovary. Low expression levels were observed for adult spleen, caruncle, and endometrium. Of considerable interest was the observation that H19 transcripts have not been detected in the mouse and human kidney or in the mouse spleen. In contrast, we observed significant expression levels in adult kidney and low expression levels in adult spleen. In a comparison of adults and fetuses, significant differences in H19 expression levels were found for liver, lung, heart, and spleen. The expression pattern in adults implies that, in addition to possible roles in embryogenesis, the H19 gene may have other functions.
(16-Oct-2006)
 

Taylor Kristen H., Jeremy F. Taylor, Stephen N. White, James E. Womack. 2006. "Identification of genetic variation and putative regulatory regions in bovine CARD15". Mammalian Genome, 17 (8): 892-901

KEYWORDS: genetic variation, regulatory regions, bovine CARD15

SUMMARY: Mutations in caspase recruitment domain 15 (CARD15) are associated with susceptibility to Crohn’s disease and Blau Syndrome. We performed comparative analyses of the bovine, murine, and human CARD15 transcripts to elucidate functionality of bovine CARD15 and examine its potential role in bovine disease resistance. Comparative analyses of intronic sequence across seven divergent species were performed to identify putative regulatory element binding motifs. High levels of interspecies conservation in sequence, genomic structure, and protein domains were detected indicating common functionality for CARD15 in cattle, human, and mouse. We identified species-specific regulatory elements in the 5′ and 3′ untranslated regions, suggesting that modes of regulation may have diverged across species. Thirty-one conserved putative regulatory element binding motifs were identified in the CARD15 intronic sequence of seven species. To assess the extent of genetic diversity within bovine CARD15, 41 individuals from two subspecies were sequenced and screened for polymorphisms. Thirty-six single nucleotide polymorphisms (SNPs) were identified. Finally, 20 subspecies-specific haplotypes were predicted with 7 and 13 unique haplotypes explaining the diversity within B. taurus taurus and B. taurus indicus animals, respectively. Strong evidence for a simple causal relationship between these SNP loci and their haplotypes with Johne’s disease was not detected.
(16-Oct-2006)
 

Morris C. A., N. C. Amyes, N. G. Cullen, S. M. Hickey. 2006. "Carcass composition and growth in Angus cattle genetically selected for differences in pubertal traits". New Zealand Journal of Agricultural Research, 49: 1–11.

KEYWORDS: Angus; puberty; weight; genetics; correlation; carcass; fat

SUMMARY: A selection experiment to change reproductive traits in Angus cattle was established in New Zealand in 1984/85. Alongside an unselected control line, three lines were set up, selected for increased age at puberty in heifers (AGE+ line), reduced age at puberty in heifers (AGE– line), or increased scrotal circumference (SC line), with the last two lines being merged at the 1992 matings (forming a new AGE– line, with continued heifer puberty selection). The heritability of the direct response (age at puberty) through to 2004 was 0.27 ± 0.04. The purpose of the present study was to investigate correlated responses in carcass composition and growth traits, in response to pubertal selection. Traits measured included weaning, yearling, and breeding-cow weights, carcass weight, dressing percentage, the weights of pericardial, omental and kidney fats, and the percentages of meat, bone, and trimmed fat. The carcass study included selection-line and control animals (n = 185; calf crops born in 1997–2002), and also back-crosses to both lines (n = 294; calf crops born in 2000–02). The divergence in age at puberty in heifers from the AGE+ and AGE– lines was 62 days (16% of the mean). For carcass traits, the only consistent line effects across both the AGE+ and AGE– lines and the back-cross lines were in pericardial fat weights of post-pubertal bulls (P < 0.05). However, where significant line differences in kidney fat weight or fore-quarter fat trim percentage occurred, they were also in the same direction as for pericardial fat (AGE+ animals fatter than AGE– animals). For heifers and steers, none of the line contrasts for fat traits was significant. The selection-line effects for weaning, yearling, and pre-calving mature cow weights (AGE+ minus AGE– means) were 2.5 ± 2.1, –7.3 ± 3.0 (P < 0.05), and 8.2 ± 3.7 kg (P < 0.05), 1.5, –2.7, and 1.8% of their respective means. The interpretation of these results was that earlier sexual maturity in heifers (AGE– line) was associated with a steeper juvenile growth curve through puberty, but ultimately the cows were lighter than in the AGE+ line and not different in fatness. Earlier sexual maturity in bulls was also associated with a steeper growth curve, but there was the suggestion from some fatness traits that the AGE– line were leaner than the AGE+ line when compared at the same age.
(16-Oct-2006)
 

Araujo, Cláudio Vieira de, Torres, Robledo de Almeida, Costa, Claudio Napolis. 2006. "Genetic modelling of daily milk yield using orthogonal polynomials in random regression". Revista Brasileira de Zootecnia, 35 (3, suppl.): 967-974.

KEYWORDS: genetic parameters; heritability.

SUMMARY: Data comprising 68,523 test day milk yield of 8,536 cows of the Holstein breed, daughters of 537 sires, distributed in 266 herds, calving from 1996 to 2001, were used to compare random regression models, for estimating variance. Test day records (TD) were analyzed by different random regression models regarding the function used to describe the trajectory of the lactation curve of the animals. Legendre orthogonal polynomials function of second, third and fourth order were used. The random regression models included the effects of herd-month-year of the control, genetic group of the animals; the frequency of the daily milk; regression coefficients for each class of age-season (in order to describe the fixed part of the lactation curve) and random regression coefficients related to the direct genetic and the permanent environmental effects. The heritability estimates obtained using the random regression models ranged from 0.122 to 0.291. The random regression model which used the fourth order Legendre polynomials was the model which better described the genetic variation of the milk yield, according to AIC test.
(16-Oct-2006)
 

Araujo, Cláudio Vieira de, Torres, Robledo de Almeida, Costa, Claudio Napolis. 2006. "Random regressions models to describe the genetic variation of milk yield in Holstein breed". Revista Brasileira de Zootecnia, 35.(3, suppl.): 975-981.

KEYWORDS: genetic evaluation; milk yield; random regression.

SUMMARY: Data comprising 68,523 test day milk yield of 8,536 cows of the Holstein breed, calving from 1996 to 2001, were used to compare random regression models, for estimating variance components. Test day records (TD) were analyzed as multiple traits, considering each TD as a different trait. The test day records were analyzed as longitudinal traits by different random regression models regarding the function used to describe the trajectory of the lactation curve of the animals. The Wilmink's exponential function, the Ali and Schaeffer logarithmic function and the Legendre orthogonal polynomials of second and fourth order were used. The comparisons among the models were based on the following criteria: estimates of variance components of the multiple-trait model and random regressions models, values of residual variance and values of the logarithms of the likelihood functions. The heritability estimates obtained using the multiple-trait model varied from 0.110 to 0.244, for the random regression models the values ranged from 0.127 to 0.301, being the largest estimates observed in the models with larger number of parameters. The random regression models which used the Legendre polynomials was the model which better described the genetic variation of the milk yield.
(16-Oct-2006)
 

Azevedo, Danielle Maria Machado Ribeiro, Martins Filho, Raimundo, Bozzi, Riccardo. 2006. "Genetic and phenotypic parameters of reproductive performance of Chianina females". Revista Brasileira de Zootecnia, 35 (3, suppl.): 982-987.

KEYWORDS: age at first calving; calving interval; heritability; repeatability.

SUMMARY: This study aimed to evaluate the reproductive performance of Chianina cows born from 1977 to 2002. Data was used to calculate age at first calving (AFC), first calving interval (CI1) and average calving intervals (avgCIs) for the whole lifetime of cows. After editing data, the number of records used for AFC, CI1 and avgCIs analyses were respectively 31,023; 23,998 and 94,497 respectively. Statistical analyses were done using the SAS program (Statistical Analysis System) and variance components were estimated by REML using the software MTDFREML fitting animal models. Means for AFC, CI1 and avgCIs were 1,037.69 ± 186.37, 457.93 ± 12.22 and 436,26 ± 12,17 days, respectively. Heritability estimates for AFC, CI1 and avgCIs were respectively 0.36 ± 0.014; 0.13 ± 0.014 e 0.05±0.004 and the repeatability for avgCIs was 0.075 ± 0.004. The use of AFC and CI1 in genetic improvement programs may lead to an increase in precocity and potential longevity. Changes in management of females may decrease avgCIs, leading to higher and faster improvement in reproductive efficiency.
(16-Oct-2006)
 

Correa, Marcela Bicca Bragança, Dionello, Nelson José Laurino, Cardoso, Fernando Flores. 2006. "Estimation of genetic parameters and (co) variance components for pre-weaning productive traits in Devon cattle in Rio Grande do Sul". Revista Brasileira de Zootecnia, 35 (3, suppl.): 997-1004.

KEYWORDS: correlations; heritability; maternal effect; pre-weaning.

SUMMARY: The objective of this study was to estimate (co)variance components and genetic parameters, such as heritabilities and correlations, and genetic and phenotypic trends for birth weight (PN), weaning weight (PD) and 205 day adjusted weight gain (GNDA). A total of 23,369 records on animals, born from 1980 through 2000, collected by PROMEBO - beef cattle improvement program of Associação Nacional de Criadores Herd Book Collares, were used. Of these animals, 16,593 had record of PN, 22,530 had of PD and 22,259 of GNDA. Analyses were performed by the restricted maximum likelihood method using the MTDFREML program. Initially, a univariate analysis was used for each trait and, afterwards, bivariate models were used in analyses relating weights at birth and weaning with pre-weaning gain. Heritabilities and standard errors obtained from univariate analyses were of 0.32 ± 0.03 for PN, 0.17 ± 0.01 for GNDA and of 0,12 ± 0,01 for PD. From bivariate analyses of PN with GNDA and of PD with GNDA, heritability estimates were of 0.35 and 0.17 and of 0,32 and 0.42, respectively. Medium heritabilities for weights and weight gains indicate that these traits efficiently respond to selection. Genetic correlation estimates was high (0.95) between PD and GNDA and low (0.15) between PN and GNDA indicating that selection for weight gain make it possible to obtain a correlated response on weaning weight, without increasing birth weight. Estimated genetic and phenotypic trends demonstrated genetic progress for GNDA and PD, while PN is on plateau, thereby, indicating favorable change in pre-weaning performance, without increasing risk of calving difficulty.
(16-Oct-2006)
 

Azevedo, Danielle Maria Machado Ribeiro, Martins Filho, Raimundo, Lobo, Raimundo Nonato Braga. 2006. "Reproductive performance of Nelore cows in the North and Northeast Regions of Brazil". Revista Brasileira de Zootecnia, 35 (3, suppl.): 988-996.

KEYWORDS: beef cattle; genetic parameters; reproductive efficiency; zebu cattle.

SUMMARY: The objective of this study was to estimate genetic and phenotypic parameters for reproductive traits of Nelore cows raised in the North and Northeast regions of Brazil. The traits studied were age at first calving (AFC), calving interval (CI), post-partum interval (PPI), number of services per conception (NSC) and gestation length (GL). The statistical analyses were done using the SAS program (Statistical Analysis System) and variance components were estimated by Restricted Maximum Likelihood method using the MTDFREML software. Means and heritability estimates for AFC, CI, PPI, NSC and GL were 45.14±10.83 months; 465.55±128.49 days; 165.76±110.29 days; 1.34±0.67 services and 295.03±5.85 days and 0.21±0.05; 0.05±0.02; 0.32±0.11; 0.05±0.04 e 0.12±0.04, respectively. The repeatability for CI, PPI, NSC and GL were, respectively, 0.05; 0.63; 0.09 and 0.22. The results suggest that despite the small genetic variability for the reproductive traits, AFC and GL must be included in selection programs. The high heritability estimate for PPI is probably associated to the structure of the data, in its majority coming from the same herd. The repeatability estimate for CI suggests that female culling based on first calving interval is not accurate and there is a risk of culling animals with probable good reproductive efficiency.
(16-Oct-2006)
 

Pimentel, Eduardo da Cruz Gouveia, Queiroz, Sandra Aidar de, Carvalheiro, Roberto. 2006. "Estimates of genetic effects in crossbred calves by different models and estimation methods". Revista Brasileira de Zootecnia, 35 (3, suppl.): 1020-1027.

KEYWORDS: biased estimation; epistasis; heterosis; multicollinearity; ridge regression.
SUMMARY: The purpose of this study was to compare estimates of genetic effects obtained using the additive-dominance model and another which included parameters for joint-additive (complementarity) and epistatic effects, as well as evaluate alternative objective criteria for choosing the lambda coefficient in ridge regression implementation. The results indicated that the criterion to be employed at the choice of lambda not only depends on the data set and the model used, but also on a previous knowledge about the phenomenon under study and the practical interpretation of estimated coefficients. When performing genetic effects evaluation, if other than additive and dominance effects are contemplated, it may be possible to identify and separate joint-additive and epistatic effects, which are usually inlaid in the heterotic effect estimated by the additive-dominance model. The use of ridge regression method can make such analyses possible even under strong multicollinearity.
(16-Oct-2006)
 

Sirol, Mirella Leme Franco Geraldini, Hadlich, Janaina Conte, Suguisawa, Liliane. 2006. "Effects of transforming a normally distributed variable into its inverse on parameters of the distribution using Monte Carlo techniques". Revista Brasileira de Zootecnia, 35 (3, suppl.): 1028-1038.

KEYWORDS: beef cattle; selection criteria; bayesian inference; average daily gain.

SUMMARY: Four simulation studies were conducted to verify the distribution of the inverse of variables with normal distribution, relatively to variances, averages, truncation points and sample sizes. The variables simulated were GMD, with normal distribution and representing average daily gain, and DIAS defined as a multiple of the inverse of GMD and representing days to reach a fixed body weight. The SAS® (1990) system was used, for simulation of the data, and for subsequent analysis of the results in all studies. The standard deviations simulated for GMD significantly affected DIAS sampling averages. The regression analyses showed a reduction on the mean and in the standard deviation of DIAS as a function of the increase in the average of GMD. Including a truncation point at about 10 to 25% of the mean value reduced the mean of GMD and increased the mean of DIAS when the coefficient of variation of GMD was above 25%. Size of the groups did not significantly affect averages of GMD or DIAS. Standard deviation and CV of GMD increased with the increase on group size. Due to the dependence between the average and the standard deviation and the variation observed in the standard deviations of DIAS as a function of group size, the use of DIAS as selection criteria may reduce the accuracy of the genetic evaluation. Therefore, in order to substitute GMD by DIAS, it is necessary the use of a method of analysis robust enough to eliminate the heterogeneity of variance.
(16-Oct-2006)
 

Knackfuss, Fabiana Batalha, Razook, Alexander George, Mercadante, Maria Eugênia Zerlotti. 2006. "Selection for yearling weight in Gir cattle. 1. Direct and correlated response in 21 years of selection". Revista Brasileira de Zootecnia, 35 (3): 715-725.

KEYWORDS: beef cattle; control population; generation coefficient; genetic change; selection intensity.

SUMMARY: Selection for yearling weight has been applied in a herd of Gir breed (80 cows, 6 sires) since 1976 and a Nelore Control herd (60 cows, 4 sires) has been used to evaluate the environmental change. Selection criteria were bull weight at 378 days (P378) in a performance test and heifer weight at 550 days (P550), under grazing conditions. The effective midparent selection differentials for P378 and P550 were 19.5 and 1.8 kg respectively for Gir and NeC, corresponding to 0.72 and 0.07 standard deviation units (s.d.u). The midparent cumulative effective selection differentials for the 2001 offspring were respectively 83.7 and 7.2 kg for Gir and NeC, corresponding to 3.17 and 0.29 s.d.u. The average generation intervals were 5.65 and 5.0 years respectively for the Gir and NeC herds. The individual generation coefficient for the 2001 offspring attained the values of 4.25 (Gir) and 4.65 (NeC). Annual genetic trends estimated by least square methodology in the Gir herd were - PN: 0.16; P210: 0.81 kg/year; GPRE: 3.02 g/day/year; P378: 2.88; P550: 2.80 kg/year; G112: 11.2 g/day/year; AM: 0.003 and AF: 0.004 m/year. Using the mixed model methodology, the estimates for these traits were lower, 0.03, and 0.28 kg/year; 1.15 g/day/year; 1.45 and 1.07 kg/year; 3.73 g/day/year; 0.003 and 0.002 m/year. The realized heritability was 0.69 and 0.64 for P378 and P550, respectively. The results indicated significant genetic response from direct selection based on individual performance information for postweaning weight as well as correlated response in pre and postweaning growth traits in a Gir herd.
(16-Oct-2006)
 

Knackfuss, Fabiana Batalha, Razook, Alexander George, Mercadante, Maria Eugênia Zerlotti. 2006. "Selection for growth traits in Gyr cattle. 2. Estimates of variances and genetic parameters due to direct and maternal effects". Revista Brasileira de Zootecnia, 35 (3): 726-732.

KEYWORDS: animal model; beef cattle; daily gain; heritability; likelihood ratio test; performance testing.

SUMMARY: Variance components and genetic parameters for growth traits of Gyr breed were estimated using univariate analyses by restricted maximum likelihood. Five models differing in the random effects were evaluated. The models included the fixed effects of month of birth, contemporary group and age of cow. According to the likelihood ratio test (LRT) the best fit for all traits measured in the pre-weaning period was obtained by the model including the direct and maternal effects (genetic and environment). Heritability estimates for birth weight (PN), weight adjusted to 120 days (P120), weaning weight adjusted to 210 days (P210) and daily weight gain in pre-weaning period (P210) were respectively, 0.31 ± 0.07, 0.14 ± 0.06, 0.23 ± 0.07, and 0.22 ± 0.07. For the post-weaning traits, the best fitting model was the one which included only the direct genetic effect. Heritability estimates for male performance test weight at 378 days (P378), heifer weight at 550 days (P550), daily weight gain during the performance test (G112), male height at 378 days (AM) and heifer's height at 550 days (AF) were respectively, 0.45 ± 0.11, 0.29 ± 0.11, 0.37 ± 0.11, 0.79 ± 0,13, and 0.36 ± 0.0. The maternal genetic and permanent environmental effects were important sources of variation only for the traits measured in the pre-weaning period.
(16-Oct-2006)
 

Perotto, Daniel, Abrahao, José Jorge dos Santos and Kroetz, Inácio Afonso. 2006. "Calving interval of Nellore, Guzerath x Nellore, Red Angus x Nellore, Marchigiana x Nellore and Simental x Nellore". Revista Brasileira de Zootecnia, 35 (3): 733-741.

KEYWORDS: beef cattle; crossbreeding; calving interval.

SUMMARY: Two hundred and eighty-six observations on interval between first and second parturition (IEP1) and 1,106 observations on interval between parturitions considering all parturitions (IEP2) of 89 Nellore (NN), 47 F1 Guzerat x Nellore (GN), 76 F1 Red Angus x Nellore (RN), 35 F1 Marchigiana x Nellore (MN) and 39 F1 Simental x Nellore (SN) cows were analyzed in this study. Least squares means for IEP1 were: 492 ± 22 d, 505 ± 25 d, 433 ± 22 d, 453 ± 27 d e 450 ± 24 d, respectively for NN, GN, RN, MN and SN. The contrasts RN - NN and RN - GN were highly significant whereas the contrasts SN - GN, MN - GN and SN - NN were significant. In the same order, LS means for the five groups for IEP2 were: 466 ± 20 d, 485 ± 22 d, 385 ± 29 d, 432 ± 30 d e 446 ± 29d, with highly significant differences for RN - NN and RN - GN while the differences RN - SN e MN - GN approached the significance level of 5%. The study also revealed important environmental effects of order of parturition, year of first parturition and month of first and second parturition of interval under study upon IEP2. It can be concluded that F1 Red Angus x Nellore cows are the best choice as genetic resources for improving reproductive performance of beef herds in the region and that judicious combination of crossbreeding with breeding season can also contribute for enhancing that performance.
(16-Oct-2006)
 

Falcao, Alencariano José da Silva, Martins, Elias Nunes, COSTA, Claudio Napolis 2006. "An evaluation of heteroscedasticity of variances of milk yield of Holstein cattle in different states using Bayesian inference via Gibbs sampler". Revista Brasileira de Zootecnia, 35 (2): 405-414.

KEYWORDS: Bayesian inference; convergence criterion; heritability; variance components; genotype × environment interaction.

SUMMAARY: Adjusted for 305 days milk yield records of Holstein cows calving from 1980 to 1993 in the states of MG, SP, PR, SC, and RS were used to investigate heterogeneity of variance and to evaluate the genotype by environment interaction. Milk production from each State was considered as a different trait and variances were assumed heterogeneous. Milk production was also analyzed using a single-trait model assuming homogeneity of variance. (Co)variance components and genetic parameters were estimated by Bayesian inference, via Gibbs sampler (GS), using a model which included season of calving, genetic group, herd-year of calving and parity as fixed effects and animal additive genetic, permanent environmental and residual as random effects. Convergence of the GS chain to the stationary distribution was diagnosed using the method described by Heidelberg & Welch (1983). The posterior precision of the variance components and the heritability were high in the single-trait analysis. Posterior mean and standard deviation (SD) of heritability of milk yield were 0,278±0,012. For the multiple-trait analysis, posterior precisions of the (co)variance components were larger for SP and PR states. Posterior means and standard errors of heritability for MG, SP, PR, SC, and RS were 0.280±0.021, 0.233±0.015, 0.280±0.012, 0.393±0.026, and 0.382±0.022, respectively. Genetic correlations for milk yield between the five states were very low and ranged from 0.070 to 0.364, suggesting the presence of genotype by environment interaction. Differences in genetic and residual variances of milk yield among the states indicate it would be necessary to account for heterogeneous variances in genetic evaluations.
(16-Oct-2006)
 

Magalhaes, Hélida Regina, El Faro, Lenira, Cardoso, Vera Lucia. 2006. "Effects of environmental factors on somatic cell count and reduction of milk yield on Holstein cows". Revista Brasileira de Zootecnia, 35 (2): 415-421.

KEYWORDS: dairy cattle; mastitis; milk yield; somatic cells.

SUMMARY: Cumulative milk yield at 305 days (MY-305) and somatic cell count (SCC) from the first to the fifth lactation of Holstein cows were analyzed in this study. Somatic cell count was logarithmically transformed to somatic cell score (SCS) that was then included in the model not only as a dependent but also as an independent variable. Year, season, and parity order all significantly affected the average SCS in this study. Data of the effect of SCS on milk yield showed significant losses on MY-305 because of the observed negative linear relationship between these two variables. Somatic cell score affected differently MY-305 from different parity orders with greater effect after the 3rd parity. Although clinical mastitis seems to cause greater economic losses, prevention and control of sub-clinical mastitis deserve more attention due to its greater prevalence leading to significant reduction on herd productivity.
(16-Oct-2006)
 

Ruas, José Reinaldo Mendes, Brandao, Felipe Zandonadi, Silva Filho, José Monteiro da. 2006. "Effect of milking frequency on production of crossbred holstein-zebu cows". Revista Brasileira de Zootecnia, 35 (2): 428-434.

KEYWORDS: calf weight; crossbred cows; daily milking; milk yield; weight gain.

SUMMARY: This trial was conducted to study the effects of daily milking frequency on milk yield, duration of lactation, incidence of mastitis, and calves body weight gain. Sixty-three crossbred Holstein-Zebu cows were equally and randomly assigned to three experimental groups according to the frequency of daily milkings as follows: once a day milking, twice a day milking, or alternating once or twice a day milking every 14 days. The duration of lactation, mammary gland health, and calf production did not differ among treatments in this study. However, cows milked twice a day yielded 24.54% more milk per lactation (699.9 kg) compared to the other milking regimes.
(16-Oct-2006)
 

Mello, Silvio de Paula, Alencar, Maurício Mello de, Toral, Fábio Luiz Buranelo. 2006. "Estimates of genetic parameters for growth and productivity traits of Canchim cows using Bayesian inference". Revista Brasileira de Zootecnia, 35 (1): 92-97.

KEYWORDS: beef cattle; body weight; days in herd; female productivity.

SUMMARY: The objective of this study was to estimate genetic parameters for body weights at weaning (PD), 12 months old (P12) and adult age (PAD), culling age (TPR, days in herd), number (ND10) and kilograms (QD10) of calves weaned up to ten years of age, total number (NDT) and total kilograms (QDT) of calves weaned during herd life, and kilograms of calves weaned per year in herd (QTPR) of Canchim (5/8 Charolais + 3/8 Zebu) females from one herd. Data consisted of 3,249, 3,111, 1,138, 1,340, 1,362, 1,362, 1,340, 1,340 and 1,340 records of PD, P12, PAD, TPR, ND10, QD10, NDT, QDT and QTPR, respectively. Variance and covariance components were estimated by bivariate analyses between PD, P12 and PAD and other production traits using Bayesian inference. The models included the additive direct, permanent environmental and residual random effects and the fixed effects year and month of birth or calving, calving age and age of the animal, depending on the trait. QD10, QDT and QTPR of each female were obtained by adjusting the weaning weights of calves for year and month of birth, sex and age of cow. Average of heritability estimates were 0.38 (PD), 0.40 (P12), 0.54 (PAD), 0.22 (TPR), 0.22 (ND10), 0.24 (QD10), 0.23 (NDT), 0.23 (QDT) and 0.32 (QTPR), indicating genetic variability to obtain response by selection. Genetic correlations between TPR (-0.02, 0.26 and -0.12), ND10 (0.04, 0.10 and -0.29), QD10 (0.37, 0.39 and -0.13), NDT (-0.03, 0.14 and -0.25), QDT (0.20, 0.33 and -0.16), QTPR (0.21, 0.28 and -0.19) and body weights (PD, P12 and PAD) suggest that selection of females based on weaning and 12-month body weights will not affect productivity. However, it may be decreased by increasing female adult body weight.
(16-Oct-2006)
 

Kaminski S., K.'Olenski, P. Brym, T. Malewski, and A. A. Sazanov. 2006. "Single Nucleotide Polymorphism in the Promoter Region of the Lactoferrin Gene and Its Associations with Milk Performance Traits in Polish Holstein–Friesian Cows". Russian Journal of Genetics, 42: 924-927

KEYWORDS: Single Nucleotide Polymorphism, Promoter Region, Lactoferrin Gene, Milk Performance Traits, Polish Holstein–Friesian

SUMMARY: Bovine lactoferrin (LTF) is a multifunctional small glycoprotein found in milk acting mainly as a defense factor in the mammary gland. Many polymorphisms have been found in the bovine LTF gene but almost none were considered as genetic markers of production traits in dairy cattle. In this study, the promoter fragment of LTF gene containing mutation (G/C) in position +32 has been amplified by PCR followed by genotyping by the SSCP and RFLP method. Three hundred fifty-eight Polish Holstein–Friesian cows were screened, giving the following frequency of genotypes: 0.628, 0.313 and 0.059 for GG, GC and CC, respectively. GLM (General Linear Model) analysis was applied to evaluate the associations of lactoferrin with milk performance traits, including SCC (somatic cell count). It was found that CC cows show significantly higher (P 0.01) protein content in milk in comparison with GG cows. The values of other milk performance traits were also higher but at nonsignificant levels. SCC in milk was the lowest in CC cows, but also at a nonsignificant level.
(16-Oct-2006)
 

Maiwashe A., K.A. Nephawe, R.R. van der Westhuizen, B.E. Mostert, H.E. Theron. 2006. "Rate of inbreeding and effective population size in four major South African dairy cattle breeds". South African Journal of Animal Science, 36 (1): 50-57.

KEYWORDS: inbreeding, effective population size, South African dairy cattle breeds

SUMMARY: Pedigree information on the registered South African Ayrshire (n = 47 116), Guernsey (n = 18 766), Holstein (n = 892 458) and Jersey (n = 314 403) breeds was analyzed to determine the rate of inbreeding and effective population sizes for the period 1960 to 2003. Inbreeding coefficients were calculated using the Animal Breeder’s Tool Kit. The mean inbreeding coefficients for 2003 were 2.02%, 2.04%, 2.30%, and 3.05% for the Ayrshire, Guernsey, Holstein and Jersey, respectively. The corresponding rates of inbreeding per year were 0.05%, 0.05%, 0.06%, and 0.07% indicating that inbreeding is accumulating at a slightly higher rate in Jersey compared to the other three breeds. However, the rates of inbreeding in the current study are still considerably lower than the acceptable rate of less than 0.5% per year. Estimates of effective population sizes were 148, 165, 137, and 108 for the Ayrshire, Guernsey, Holstein and Jersey, respectively. Results indicate that the impact of inbreeding on genetic variability is still minimal. However, the impact of inbreeding on phenotypic performance on traits of economic importance was not investigated in the current study and should therefore receive future consideration.
(16-Oct-2006)
 

Mostert B.E., H.E. Theron, F.H.J. Kanfer and E. van Marle-Kِster. 2006. "Test-day models for South African dairy cattle for participation in international evaluations". South African Journal of Animal Science, 36 (1): 58-70

KEYWORDS: Test-day models, South African dairy cattle, international evaluations

SUMMARY: Variance components and breeding values of production traits and somatic cell score of South African Guernsey, Ayrshire, Holstein and Jersey breeds have been estimated using a multi-lactation repeatability test-day model, including tests of the first three lactations as repeated measures and fitting the permanent environmental effect across lactations. Multitrait evaluations were done for the production traits (milk, butterfat and protein) and single trait evaluations for somatic cell score. Heritability estimates were comparable with yield and somatic cell score estimates obtained by test-day models from other countries (17-24% for milk yield; 10-13% for butterfat yield; 14-19% for protein yield and 6-8% for somatic cell score). Proofs of qualifying sires were sent to the International Bull Evaluation Service (INTERBULL) for participation in the March 2005 test runs. Genetic correlations between South Africa and other participating countries, estimated by INTERBULL, compared well with those amongst the other participating countries. Trend validation tests were successful using this methodology for all traits and breeds except for somatic cell score of the Guernsey breed, due to insufficient data for this trait. South Africa can now participate in routine INTERBULL evaluations to obtain Multiple Across Country Evaluation (MACE) breeding values, using this methodology.
(16-Oct-2006)
 

Mostert B.E., H.E. Theron, F.H.J. Kanfer, E. van Marle-Kِster. 2006. "Comparison of breeding values and genetic trends for production traits estimated by a Lactation Model and a Fixed Regression Test-day Model". South African Journal of Animal Science, 36 (2): 71-78.

KEYWORDS: breeding values, genetic trends, Lactation Model, Fixed Regression Test-day Model

SUMMARY: A comparison of breeding values and genetic trends of production traits from two models is made. One set of breeding values and trends was estimated by the September/October 2003 South African National Genetic Evaluation, using a Lactation Model (LM). The other set was obtained in the 2004 South African National Genetic Evaluation, using a Fixed Regression Test-day Model (TDM). This comparison is made for Ayrshire, Guernsey, Holstein and Jersey cows participating in the South African Dairy Animal Improvement Scheme. Specific differences between the two models were documented, with differences in statistical methodology and inclusion of test-day records of the first three parities in the TDM vs. only first lactation 305-day yields in the LM, as the main differences. Significant reranking of especially cows and unproven sires occurred between the models. Genetic trends of the TDM were not as steep as those from the LM, as the trait that was selected was first lactation yield, while the TDM trends reflect genetic progress over the first three parities.
(16-Oct-2006)
 

Muller C.J.C., S.W.P. Cloete, J.J. Olivier, J.A. Botha, H. de Waal. 2006. "Heritability of live weight and condition score in a Holstein herd and correlations with milk traits–preliminary estimates". South African Journal of Animal Science, 36 (2): 79-88

KEYWORDS: Heritability, live weight, condition score, Holstein herd

SUMMARY: Genetic and e live weight nvironmental parameters for live weight and condition score have been determined for Holstein cows. Genetic correlations with milk traits were also derived. Monthly records were modelled by cubic splines, while the direct, additive effects of animal and the temporary environment (defined as cow environmental effects within lactations) were fitted as random. Lactation number interacted with monthly trends in cow live weight. Cows lost weight in the early part of the lactation. This reduction in live weight was probably because of a loss in body reserves, as suggested by a lower condition score. Cows gained live weight towards the end of lactation. The ultimate live weight of cows increased with parity because of ongoing growth. The heritability (h²) estimate for live weight was high at 0.65 ± 0.04, albeit still within the expected range. Condition score had a medium h² of 0.24 ± 0.05. Genetic and phenotypic correlations of live weight with milk yield were positive, i.e. 0.19 ± 0.14 and 0.12 ± 0.05, respectively, while correlations of condition score with milk yield were negative, i.e. 0.42 ± 0.15 and -0.17 ± 0.04, respectively. Although live weight could be used as an indirect indicator of feed intake and efficiency of milk production, other body conformation traits could also be used. There is a need in the South African dairy industry for a selection index based on production parameters and some traits such as live weight, condition score or specific conformation traits. However, a large participation of animals in milk recording and measurement of such traits is a prerequisite for such developments.
(16-Oct-2006)
 

du Plessis I., L.C. Hoffman, F.J. Calitz. 2006. "Influence of reproduction traits and pre-weaning growth rate on herd efficiency of different beef breed types in an arid sub-tropical environment". South African Journal of Animal Science, 36 (2): 89-98.

KEYWORDS: reproduction traits, pre-weaning growth rate, herd efficiency, beef breed types, arid sub-tropical environment.

SUMMARY: The efficiency of Simmentaler cross (SX), Bonsmara cross (BX), Afrikaner (AF) and Nguni (NG) cowherds to produce weaner calves under natural sweetveld conditions was investigated. The respective cowherds were selected to differ with regard to frame size (SX > BX > AF > NG). The AF cows, young (13 to 15 months old) heifers and herd had significantly lower pregnancy rates than the SX, BX and NG cows, young heifers and herds. The weaning rate for NG was significantly higher (15%) than SX, and although not significant, it was still 5 and 8% respectively higher than BX and AF. Weaning weight and pre-weaning growth parameters differed significantly between breed types (SX > BX > AF > NG). Cow efficiency was significantly lower for the AF cows than for the SX, BX and NG cows. The NG herd was more efficient than the other three herds, while the AF herd was the least efficient. Differences in herd efficiency were mainly due to differences in the reproduction rates of the respective herds. The reproduction and calf survival rates were the most important production traits that affected herd efficiency. Management practices should be adapted to maximize the reproduction rate of the females, including the young heifers, to maximise herd efficiency.
(16-Oct-2006)
 

Lirón, Juan Pedro Pilar Peral-García, and Guillermo Giovambattista. 2006. "Genetic Characterization of Argentine and Bolivian Creole Cattle Breeds Assessed through Microsatellites". Journal of Heredity, 97(4):331-339;

KEYWORDS: Genetic Characterization, Creole Cattle Breeds, Microsatellites

SUMMARY: In the present report, the polymorphisms from 9 microsatellites were used to assess genetic diversity and relationships in 4 Creole cattle breeds from Argentina and Bolivia, 4 European taurine breeds, and 2 American zebu populations. The Creole populations display a relatively high level of genetic variation as estimated by allelic diversity and heterozygosity, whereas the British breeds displayed reduced levels of genetic diversity. The analysis of molecular variance indicated that 7.8% of variance can be explained by differences among taurine and zebu breeds. Consistent with these results, the first principal component (PC), which comprised the 40% of the total variance, clearly distinguishes these 2 groups. In addition, all constructed phylogenetic trees cluster together Nelore and Brahman breeds with robust bootstrap values. Only 1% of variance was due to difference between American Creole and European taurine cattle. Although this secondary split was supported by the classical genetic distance and the second PC (15%), the topology of trees is not particularly robust. The presence of zebu-specific alleles in Creole cattle allowed estimating a moderate degree of zebu admixture. When these data were compared with mitochondrial and Y chromosomal studies, a clearl pattern of male-mediated introgression was revealed. The results presented here contribute to the understanding of origin and history of the American Creole cattle.
(16-Oct-2006)
 

Çilek Süleyman, Mehmet Emin Tekin. 2006. "Calculation of Adjustment Factors for Standardizing Lactations to Mature Age and 305-Day and Estimation of Heritability and Repeatability of Standardized Milk Yield of Simmental Cattle Reared on Kazova State Farm". Turkish Journal of Veterinary and Animal Sciences, 30:283-289.

KEYWORDS: Simmental, milk yield, adjustment factors, repeatability, heritability

SUMMARY: Adjustment factors of lactation milk yield to mature age and 305-day were calculated and heritability and repeatability of milk yield were estimated for Simmental cows reared on Kazova State Farm. A total of 1549 lactation records of Simmental cows reared on Kazova State Farm between 1992 and 2002 were used. The factors for standardizing incomplete lactations to 305-day were estimated by taking 7 calving age groups into consideration (2, 3, 4, 5, 6-8, 9 and 10 years of age and older). The factors for standardizing to mature equivalent estimated by polynomial regression are between the 24th and 143rd month and older. The repeatability of milk yield was estimated as 0.44 ± 0.028 using intra- class correlation. Heritability of milk yield was estimated using paternal half-sib correlation. Heritability of milk yield for all lactations was estimated as 0.24 ± 0.08. Heritability for first lactation was estimated as 0.30 ± 0.154.
(16-Oct-2006)
 

Özlütürk Abdülkadir, Mete Yanar, Naci Tüzemen, Sinan Kopuzlu. 2006. "Calving and Preweaning Growth Performance Traits of Calves Sired by Charolais, Simmental and Eastern Anatolian Red Bulls". Turkish Journal of Veterinary and Animal Sciences, 30: 257-263.

KEYWORDS: Calf, breeds of sire, growth traits, beef cattle, calving traits

SUMMARY: Charolais (C)-, Simmental (S)-, and Eastern Anatolian Red (EAR)-sired calves born in 2 locations in Eastern Anatolia were compared in terms of calving traits and preweaning growth characteristics. Breed of sire effects were significant (P < 0.01) for birth weight, 205-day weaning weight, average daily weight gain from birth to weaning, and some body measurements at birth. S- and C-sired calves were heavier at birth and larger for most body measurements at birth than EAR-sired calves. The C- and S-sired calves also had higher 205-day weight than the EAR-sired calves. Although the level of calving difficulty was higher in the S and C crosses, the differences were not statistically significant. Male calves had significantly (P < 0.01) heavier birth and 205-day weights, higher preweaning average daily gain and greater body measurements (e.g., height at withers, heart girth and cannon bone girth) than females. Location differences were also significant (P < 0.01) for survival rate from birth to weaning, preweaning growth rate and 205-day weight. In conclusion, although C- and S-sired calves performed similarly for most traits, all parameters of the preweaning growth were higher in calves sired by S and C bulls than in calves sired by EAR bulls. Therefore, both C and S could be considered as sire breeds for crossbreeding programs to be implemented in Eastern Anatolia, since these breeds did not cause an adverse influence on the calving and growth traits of the crossbred calves.
(16-Oct-2006)
 

Forabosco Flavio, Paul Boettcher, Riccardo Bozzi, Francesco Filippini, Piter Bijma. 2006. "Genetic selection strategies to improve longevity in Chianina beef cattle". Italian Journal of Animal Science, 5: 117-127.

KEYWORDS: Chianina, Selection program, Profit, Longevity, Breeding goals.

SUMMARY: Longevity in beef cattle is an important economic trait. Including this trait in a breeding scheme increases profit and has a positive impact on the well-being and welfare of the animals. The aim of the present study was to evaluate the consequences of alternative selection strategies to include longevity in different breeding schemes using deterministic simulation. Different schemes were compared and economic (EcW) and empirical weights (EmW) were used to evaluate the responses. The empirical weights of average daily gain (ADG) and muscularity (MU) were identical because both traits have an identical importance for the breeders. Economic weights have been derived from profit equations. Traits used in the Base scenarios were: average daily gain pre-performance test (ADG1), average daily gain during the performance test (ADG2) and muscularity (MU); longevity (L) was included in the alternative schemes. When longevity was included both in the breeding index and in the breeding goal (scenario A-2), the total longevity response using EmW and EcW was +2.97 d/yr and +4.92 d/yr, respectively. The total economic response for scenario A-2 using EmW and EcW were 3.020 €/yr and 3.342 €/yr, respectively, and the total response in units of Bull Selection Index were +0.699 and +0.678, respectively. Longevity decreased when it was not included in either the breeding goal or in the breeding index (scenario Base), and economic response was the lowest found. The results of the current study indicate that the highest total response using either economic weights or empirical weights was found when information on longevity was included both in the breeding index and in the breeding goal (scenario A-2).
(16-Oct-2006)
 

Bozzi Riccardo, Oreste Franci, Flavio Forabosco, Carolina Pugliese, Alessandro Crovetti, Francesco Filippini. 2006. "Genetic variability in three Italian beef cattle breeds derived from pedigree information". Italian Journal of Animal Science, 5: 129-137.

KEYWORDS: Pedigree analysis, Italian beef cattle, Genetic diversity, Probabilities of gene origin

SUMMARY: The aim of the present work was to estimate genetic variability in Chianina (CH), Marchigiana (MC) and Romagnola (RO) breeds using pedigree information. Different approaches based on probability of identity-by-descent (effective population size through an increase in inbreeding Ne) or probability of gene origin (total number of founders f, effective number of founders fe, ancestors fa and founder genomes fg) were used. Reference populations were defined using female animals born between 1996 and 2000 where both parents are known. Generation intervals were 5.35, 4.93 and 5.15 years for CH, MC and RO, respectively. The total number of founders were 7092, 11947, 3928, for CH, MC and RO, respectively. Complete generation equivalent showed the relative high quality of pedigree information: 5.66 for CH, 4.54 for MC and 4.95 for RO. For CH, MC and RO, respectively, a fe value of 152.1, 70.9 and 89.8, a fa value of 73.6, 48.0 and 59.5 and a fg value of 39.5, 25.0 and 38.5, were calculated. When inbreeding was used effective population sizes were 138, 122 and 124 for CH, MC and RO, respectively. Parameters derived from the probabilities of gene origin were variable among the investigated breeds and the results for MC demonstrate the need to pay specific attention to breeding strategies.
(16-Oct-2006)
 

d’Angelo Francesca, Elena Ciani, Agostino Sevi, Marzia Albenzio, Roberta Ciampolini, Dario Cianci. 2006. "The genetic variability of the Podolica cattle breed from the Gargano area. Preliminary results". Italian Journal of Animal Science, 5:, 79-85.

KEYWORDS: Microsatellites, Cattle, Genetic variability, Polymorphism, Heterozygosis.

SUMMARY: The Podolica cattle breed is autochthonous of Southern Italy and denoted by its particular rusticity. This study presents the preliminary results of the genetic characterization of the Podolica breed using DNA STR markers. A total of 20 microsatellite loci were analysed in 79 individuals reared in the Gargano area. Number of polymorphisms, allele frequencies, deviations from Hardy-Weinberg proportions, linkage disequilibrium between loci and genetic similarities between animals were calculated. The results showed a high deficiency of heterozygotes, the observed mean of heterozygosis being 0.449, whereas the expected mean was 0.766. Many markers showed also deviations from the Hardy-Weinberg proportions and significant linkage disequilibrium between loci. However the genetic similarity within the population was low (0.281) and the average number of alleles per locus was high (10), representing a high genetic variability. In order to explain these results, a stratification of the breed in sub-populations with a high interior genetic homogeneity but markedly differentiated one from each other could be hypothesized; this situation probably derived from nonrandom mating within each herd (consanguinity) and from the lack of exchange of genetic material between the herds. A further study is needed on a wider sample and extending the analysis to FAO-ISAG microsatellite panel in order to confirm this hypothesis. This could eventually provide the information necessary for the correct management of the reproductive schemes and for genomic traceability of meat production.
(16-Oct-2006)
 

Andrea Rolando, Liliana Di Stasio. 2006. "Short Communication: MC1R gene analysis applied to breed traceability of beef". Italian Journal of Animal Science, 5: 87-91.

KEYWORDS: Cattle, Beef, MC1R gene, Traceability.

SUMMARY: Since the breed of origin highly affects the beef price, reliable methods are needed to detect incorrect declarations. As most breeds are standardised for coat colour, the Melanocortin 1 Receptor gene (MC1R), involved in the regulation of eu/pheomelanins synthesis, has been suggested as marker for breed traceability of products of animal origin. The aim of this investigation is to characterise the main breeds reared in the Piedmont Region by MC1R locus and to apply the analysis of the locus to breed traceability of beef cuts purchased in different outlets of the Region. A total of 168 DNA samples of four cattle breeds (Piemontese, Blonde d’Aquitaine, Italian Friesian and Aosta Red Pied) were analysed for MC1R locus by PCR-RFLP. In addition, 28 DNA samples from beef with breed indication were tested. Piemontese and Blonde d’Aquitaine were monomorphic for the E+ and e allele, respectively. In the Friesian breed the EdEd genotype was the most frequent, but Ede was also observed (2%). Aosta Red Pied was the most variable breed, with the presence of the three alleles and five genotypes out of six. The comparison of the genotypic distribution in the four breeds clearly indicates that it is possible to distinguish among Piemontese, Blonde d’Aquitaine and Friesian breeds, but the same is not true for Aosta Red Pied, which has genotypes in common with the other breeds. The results on beef samples revealed a high percentage of mislabelling (about 18%), which concerned Friesian breed and crossbreds. These results indicate that MC1R locus is an effective marker in breed traceability of beef, when the involved breeds are characterised by different genotypes. Moreover, compared to other genetic markers, it has the great advantage of not requiring DNA reference samples. This survey, though limited, has revealed a high percentage of incompatibilities. Therefore, the analysis of MC1R locus is recommended in the framework of product certification, at least for random controls within a system aimed at preventing fraud.
(16-Oct-2006)
 

Perelygin Andrey A., Teri L. Lear, Andrey A. Zharkikh, Margo A. Brinton. 2006. "Comparative analysis of vertebrate EIF2AK2 (PKR) genes and assignment of the equine gene to ECA15q24-q25 and the bovine gene to BTA11q12-q15". Genetic Selection Evolution, 38: 551-563

KEYWORDS: translation initiation factor, innate immunity, phylogenetic analysis, FISH mapping.

SUMMARY: The structures of the canine, rabbit, bovine and equine EIF2AK2 genes were determined. Each of these genes has a 5' non-coding exon as well as 15 coding exons. All of the canine, bovine and equine EIF2AK2 introns have consensus donor and acceptor splice sites. In the equine EIF2AK2 gene, a unique single nucleotide polymorphism that encoded a Tyr329Cys substitution was detected. Regulatory elements predicted in the promoter region were conserved in ungulates, primates, rodents, Afrotheria (elephant) and Insectifora (shrew). Western clawed frog and fugu EIF2AK2 gene sequences were detected in the USCS Genome Browser and compared to those of other vertebrate EIF2AK2 genes. A comparison of EIF2AK2 protein domains in vertebrates indicates that the kinase catalytic domains were evolutionarily more conserved than the nucleic acid-binding motifs. Nucleotide substitution rates were uniform among the vertebrate sequences with the exception of the zebrafish and goldfish EIF2AK2 genes, which showed substitution rates about 20% higher than those of other vertebrates. FISH was used to physically assign the horse and cattle genes to chromosome locations, ECA15q24-q25 and BTA11q12-15, respectively. Comparative mapping data confirmed conservation of synteny between ungulates, humans and rodents.
(16-Oct-2006)
 

Schaeffer L. R. (2006) Journal of Animal Breeding and Genetics (123), 4, 218-223.

KEYWORDS: SNPs, breeding values, selection.

SUMMARY: animals can be genotyped for thousands of single nucleotide polymorphisms (SNPs) at one time, where the SNPs are located at roughly 1-cM intervals throughout the genome. For each contiguous pair of SNPs there are four possible haplotypes that could be inherited from the sire. The effects of each interval on a trait can be estimated for all intervals simultaneously in a model where interval effects are random factors. Given the estimated effects of each haplotype for every interval in the genome, and given an animal's genotype, a ‘genomic’ estimated breeding value is obtained by summing the estimated effects for that genotype. The accuracy of that estimator of breeding values is around 80%. Because the genomic estimated breeding values can be calculated at birth, and because it has a high accuracy, a strategy that utilizes these advantages was compared with a traditional progeny testing strategy under a typical Canadian-like dairy cattle situation. Costs of proving bulls were reduced by 92% and genetic change was increased by a factor of 2. Genome-wide selection may become a popular tool for genetic improvement in livestock.
(16-Oct-2006)
 

Koenig S., H. Simianer (2006) “Approaches to the management of inbreeding and relationship in the German Holstein dairy cattle population.” Livestock Science 103, 40–53

KEYWORDS: Dairy cattle, Inbreeding, Relationship, Optimum genetic contributions.

SUMMARY: the aim of this study was to estimate the current level of inbreeding in the German cow population and for bull dams born in Germany, to find out sires most related to different subsets of their breed and to demonstrate the negative effect of homozygosity in the case of complex vertebral malformation (CVM). Further on, the application of optimum genetic contribution (OGC) theory for the selection of bull dams and bull sires in different breeding scenarios was investigated. Levels of inbreeding for the cow population were in a low range from 0.97% to 1.70% evaluating birth years from 1996 to 1999 in a total dataset of 244,427 registered Holstein cows. The inbreeding coefficient of 8030 bull dams was much higher, i.e. 3.71%, for the birth year 1999. Coefficients of relationship were calculated by classes of estimated breeding values (EBV) for production traits showing highest values above 7% in the two highest EBV-classes. A more relaxed constraint on increase in inbreeding allowed even higher expected genetic gain whereas a more severe constraint resulted in more equal contributions of selected bull sires. Contributions from 21 selected bull sires and 30 selected bull dams for a scenario at 5% constrained relationship were used to develop a specific mating plan to minimise inbreeding in the short term in the following generation applying a simulated annealing algorithm. The expected coefficient of inbreeding of progeny was 66.3% less then the one resulting from random mating. Mating programs can address inbreeding concerns on the farm, at least in the short term, but long-term control of inbreeding in a dairy population requires consideration of relationships between young bulls entering AI progeny test programs. Significantly better EBVs of CVM-free bulls compared with CVM-carriers for the paternal fertility justify the application of OGC for elite matings.
(16-Oct-2006)
 

Maltecca C., Khatib H., Schutzkus V.R., Hoffman P.C., Weigel K.A. (2006) “Changes in conception rate, calving performance, and calf health and survival from the use of crossbred Jersey x Holstein sires as mates for Holstein dams” J. Dairy Sci. 89(7):2747-54.

KEYWORDS: crossbreeding; dairy calf; health; immune-function

SUMMARY: Differences in conception rates in matings of Holstein sires (HS) or F1 Jersey x Holstein sires (JHS) to Holstein dams in experimental herds were evaluated, as were differences in birth weight, dystocia, serum protein, serum IgG, fecal consistency, respiratory disease, and perinatal and preweaning mortality among the resulting calves. When mated to randomly chosen lactating Holstein cows, HS and JHS did not differ in male fertility. Calves from HS and multiparous Holstein dams were 1.9 kg heavier than calves from JHS and multiparous Holstein dams, leading to greater likelihood of dystocia. Calves from JHS and multiparous Holstein dams had higher serum protein and serum IgG levels between 24 and 72h of age, as well as lower rates of perinatal and preweaning morality than calves from HS and multiparous or primiparous Holstein dams. Mean fecal consistency scores from birth to 7d of age and number of days with scours tended to be lower among calves from crossbred sires, compared with calves from HS. No differences were observed in the incidence or severity of respiratory disease. Results of this study suggest that introduction of Jersey genes via crossbreeding may lead to a reduction in dystocia and improvements in calf health and survival in Holstein herds. Future studies should address other traits related to dairy farm profitability, including milk composition, female fertility, longevity, feed efficiency, and resistance to infectious and metabolic diseases.
(16-Oct-2006)

 

Drögemüller C., Ottmar Distl (2006) “Genetic analysis of syndactyly in German Holstein cattle.” The Veterinary Journal 171, 120-125.

KEYWORDS: syndactyly, Mulefoot, Cattle, Microsatellite, Linkage.

SUMMARY: in this work, congenital syndactyly with a variable number of affected feet was observed in eight black and white German Holstein calves. Analysis of the pedigree data revealed that all affected individuals could be traced back to a single founder. The pedigree was consistent with monogenic autosomal recessive inheritance and variable expressivity. Bovine syndactyly or ‘‘mulefoot’’ has been previously shown to map on the telomeric end of bovine chromosome 15 and we performed PCR genotyping of microsatellite markers spanning 27 cM of this chromosomal region to test the new cases for genetic linkage with the phenotype. The results confirmed the chromosomal location of the mulefoot gene in this pedigree. Furthermore the study demonstrated that although marker testing has been available for nearly a decade the use of mulefoot carriers in cattle breeding remains uncontrolled. The presented family provides a resource for positional cloning of the causative mutation.
(21-July-2006)

Guimarães, P.H.S., Madalena, F.E. Cezar, I.M. 2006. "Comparative economics of Holstein/Gir F1 dairy female production and conventional beef cattle suckler herds–A simulation study". Agricultural Systems, 88 (2-3): 111-124.

KEYWORDS: Beef cattle; F1 Holstein × Gir; F1 Angus × Nelore; Nelore; Economic performance.

SUMMARY: Three cow–calf production systems were compared using simulation: N (straightbred Nelore), AN (Nelore cows producing Angus by Nelore calves) and HG (Gir cows producing Holstein by Gir calves). All three systems produced their own straightbred replacement females. Male calves were sold at weaning and female calves in excess of those required to keep the herd size constant were sold at one year of age. In the base situation, F1 HG females were priced at twice as much as the price per kg of the beef male calves, according to present market values. Typical 1000 ha beef cattle farms were simulated for each system, based on Brachiaria brizantha pastures managed according to recommended practices. Herd dynamics were controlled by reproduction and survival. Literature figures on monthly pasture nutrient production, live weights and milk yield were used to estimate nutrient requirements to match stocking rate to nutrient availability in each system. For calving rate set to 0.8 in all three systems, the total numbers of cows for the N, AN and HG systems were, respectively, 803, 795 and 885 and the total live weight sold annually was 129,070, 133,120 and 127,680 kg. The annual economic return on investment was 5.21%, 5.81% and 10.84%, respectively, for the N, AN and HG systems. Reducing the relative price of the HG heifers diminished the economic superiority of this system over N and AN. The difference was zero when the price of HG heifers was reduced to approximately 1.2 times the beef calf price. This also happened when the calving rate of the Gir cows was set to 0.6 keeping N cows at 0.8 or higher.
(21-July-2006)

Villalba, D., Casasús, L., Sanz, A., Bernués, A., Estany, J., Revilla, R. 2006. "Stochastic simulation of mountain beef cattle systems". Agricultural Systems, 89 (2-3): 414-434

KEYWORDS: Simulation; Stochastic models; Beef cattle; Feeding strategies.

SUMMARY: A stochastic model for simulating mountain beef cattle systems was described and validated using real data. The model was able to properly simulate complex batches of animals with different initial characteristics and so obtain results about the mean and variance of animal productive and reproductive outputs. Model was used to simulate four feeding strategies during winter period in the conditions of autumn calving in the Spanish Pyrenees. The simulated strategies were CONTROL: 100% of recommendations for the mean animal; LOW1: as 24% restriction from the amount of energy provided to CONTROL, applied only during lactation; LOW2: the same of LOW1, but was applied only the last two thirds of lactation; LOW3: 16% restriction from CONTROL applied at late gestation and first third of lactation. Simulated results showed that restrictions around 25% of the total winter energy requirements of beef cows in housing conditions are possible and sustainable. The best option taking into account reproductive performance and outputs variability seems to be a continuous restriction during all lactation (strategy LOW1). On the other hand, an extensification policy implying extended grazing till mid or late December with housing afterwards (strategy LOW3), is also possible and will have no negative consequences on calf growth (only viability of young calves being outdoors in autumn should be evaluated), but can affect the PPA of cows and so the herd reproductive performance could be compromised in the long term.

Muncie, S.A., Cassady, J.P., Ashwell, M.S. 2006. "Refinement of quantitative trait loci on bovine chromosome 18 affecting health and reproduction in US Holsteins". Animal genetics, 37(3): 273-275.

KEYWORDS: Bos Taurus, chromosome 18, pregnancy rate, quantitative trait locus

SUMMARY: Selection for increased milk yield is associated with decreased fertility in US Holsteins. Previously, a putative quantitative trait locus (QTL) on chromosome 18 affecting daughter pregnancy rate (DPR) was identified in one family. The aim of this study was to determine the validity of the QTL using additional markers and an extended pedigree. Twelve markers were genotyped in 940 descendants of the original sire in which the QTL was identified. Analysis of the extended pedigree detected significant and suggestive QTL for DPR, productive life and somatic cell score. Further analysis is underway to refine the QTL region so that positional candidate genes can be identified.
(21-July-2006)

Roy, R., Ordovas, L., Zaragoza, P., Romero, A., Moreno, C., Altarriba, J., Rodellar, C. 2006. "Association of polymorphisms in the bovine FASN gene with milk-fat content". Animal genetics, 37(3): 215-218.

KEYWORDS: candidate gene, fatty acid synthase, linkage disequilibrium, single nucleotide polymorphisms

SUMMARY: Fatty acid synthase (FASN) is a multifunctional protein that carries out the synthesis of fatty acids so it plays a central role in de novo lipogenesis in mammals. Previously, the genetic structure and expression of the bovine FASN gene has been defined. Previous mapping studies placed FASN on BTA19 (19q22) where several quantitative trait loci (QTL) affecting milk-fat content and related traits have been described. This study was conducted to identify polymorphisms in the bovine FASN gene and to study their association with milk-fat content. The bovine FASN gene was screened for polymorphisms in two cattle breeds. Sequence analysis revealed several single nucleotide polymorphisms (SNPs), and two of them were analysed: a G>C substitution in the untranslated exon 1 (g.763G>C), altering a potential Sp1 transcription factor-binding site, and an A>G substitution in exon 34 (g.16009A>G), which determines a non-conservative substitution of threonine by alanine. Allele-specific amplification of the SNPs in FASN revealed significant frequency differences for both polymorphisms in Holsteins with high and low breeding values for milk-fat content. The intragenic haplotypes comprising exon 1 (alleles G and C) and exon 34 (alleles A and G) polymorphisms were studied, and the existence of linkage disequilibrium between these SNPs was found (DCG = 0.048, P < 0.001). The results suggest that the FASN gene polymorphisms contribute to variation in milk-fat content. It is proposed that the bovine FASN gene is a candidate gene for a milk-fat content QTL.

Barendse, W., Bunch, R.J., Harrison, B.E., Thomas, M.B. 2006. "The growth hormone 1 GH1:c.457C>G mutation is associated with intramuscular and rump fat distribution in a large sample of Australian feedlot cattle". Animal genetics, 37(3): 211-214.

KEYWORDS: cattle, DNA, fat deposition, fat depots, growth hormone, marbling, rump fat

SUMMARY: The GH1:c.457C>G exon 5 missense mutation in the bovine growth hormone 1 (GH1) gene that causes the replacement of leucine (L) with valine (V) was investigated in 1027 cattle with primarily Angus and Shorthorn breeding from Australian feedlots. The allele frequency of the GH1:c.457C allele was 0.77 in Angus and 0.76 in Shorthorn. The GH1:c.457C allele was associated with lower marbling (P = 0.0472), and the average effect of allele substitution was −0.22 of a phenotypic standard deviation. This allele was also associated with slightly higher rump fat (P = 0.0541) and the average effect of allele substitution was 0.11 SD. Marbling and rump fat were not strongly correlated (r = 0.097, P < 0.01) in this data set. This mutation had no significant effect on eye muscle area or hot dressed carcass weight (P > 0.1). Given these relationships, the differences between GH1 alleles could be the result of differential deposition of fat in fat depots.
(21-July-2006)

Bittencourt, T.C.C., Lobo, R.B., Bezerra, L.A.F. 2006. "Economic values for breeding goal traits for Brazilian beef cattle production". Arquivo Brasileiro de Medicina Veterinária e Zootecnia, 58(2): 196-204.

KEYWORDS: beef cattle; breeding objective; economic value.

SUMMARY: Breeding objectives were developed for beef cattle production under typical economic and environmental conditions of central Brazil. The traits considered were: calves weaned per cow/year (NCW), weaning weight (WW), carcass weight (CW) and food intake. In the study, two systems were examined, a cow-calf system (surplus calves sold after weaning) and a cow-calf enterprise (in which surplus calves are raised for slaughter). In the first, income is from the sale of male calves and surplus heifers after weaning and of culled cows. In the second, the income is from the sale of steers, surplus heifers and culled cows. For both situations, the profit (US$/cow/year) was estimated by the difference between revenue and costs. The economical values (EV) were calculated as the change in profit resulting from a unit change in each trait, as other traits remained unchanged. The trait with greatest economic value was NCW, followed by food intake, CW and WW. The order of importance when values were in additive genetic standard deviation units were feed intake, CW, NCW and WW.
(21-July-2006)

Alford, A.R., Hegarty, R.S., Parnell, P.F., Cacho, O.J., Herd, R.M., Griffith, G.R. 2006. "The impact of breeding to reduce residual feed intake on enteric methane emissions from the Australian beef industry". Australian Journal of Experimental Agriculture, 46(7): 813–820

KEYWORDS: beef industry, greenhouse gas, feed efficiency, residual feed intake.
SUMMARY: The expected reduction in methane emissions from the Australian beef herd resulting from using bulls identified as being more feed efficient as a result of having a lower residual feed intake (RFI) was modelled, both in a single herd in southern Australia and in the national herd. A gene flow model was developed to simulate the spread of improved RFI genes through a breeding herd over 25 years, from 2002 to 2026. Based on the estimated gene flow, the voluntary feed intakes were revised annually for all beef classes using livestock populations taken from the Australian National Greenhouse Gas Inventory (NGGI). Changes in emissions (kg methane/animal.year) associated with the reduction in feed intake were then calculated using NGGI procedures. Annual enteric methane emissions from both the individual and national herd were calculated by multiplying the livestock numbers in each beef class by the revised estimates of emissions per animal. For an individual adopting herd, the annual methane abatement in year 25 of selection was 15.9% lower than in year 1. For the national herd, differential lags and limits to adoption were assumed for northern and southern Australia. The cumulative reduction in national emissions was 568 100 t of methane over 25 years, with annual emissions in year 25 being 3.1% lower than in year 1. It is concluded that selection for reduced RFI will lead to substantial and lasting methane abatement, largely as a consequence of its implementation as a breeding objective for the grazing beef herd.
(21-July-2006)

Graham, J.F., Bernaud, E., Deland, M.P.B. 2006. "Sire and dam breed effects on fatty acid profiles in the longissimus dorsi muscle and subcutaneous fat of beef cattle". Australian Journal of Experimental Agriculture, 46(7): 913–919

KEYWORDS: breed, cattle, fatty acids, intramuscular fat, subcutaneous fat

SUMMARY: This study investigated the effect of sire and dam breed on the fatty acid profiles of muscle and subcutaneous fat in beef cattle. Seven hundred and ninety-three steer and 222 female progeny derived from mating Angus and Hereford cows to Angus, Hereford, Limousine and Simmental bulls, were slaughtered at around 2 years of age (about 540 kg liveweight). The mean fat content of the longissimus dorsi muscle ranged from 4.6% for the Limousine-sired cattle to 6.0% for the Angus-sired cattle. Breed differences occurred in the majority of fatty acids from the intramuscular fat, but fewer differences were observed from the subcutaneous fat. The Limousine- and Simmental-sired progeny had less (P<0.001) saturated fat and more (P<0.001) unsaturated intramuscular fat compared with the Angus- and Hereford-sired cattle. The Angus and Simmental cattle had more (P<0.001) monounsaturates than the Limousine and Hereford cattle. There were differences (P<0.001) in the level of intramuscular polyunsaturates between all 4 sire-breeds, the Limousine having the highest and Angus the lowest. Simmental progeny had significantly higher levels of polyunsaturated fatty acids, compared with the Hereford-sired progeny, as well as a higher monousaturated : saturated fatty acid ratio. Hereford-sired progeny had a lower (P<0.001) monousaturated : saturated fatty acid ratio in the intramuscular fat. Intramuscular fatty acids were affected by dam breed, with progeny of Hereford cows having a higher percentage of unsaturated fatty acids (P = 0.015), lower saturated fatty acids (P = 0.011), and a higher monousaturated : saturated fatty acid ratio (P = 0.028) than those of Angus cows. There was no effect of dam breed on the totals of the different fatty acid groups in the subcutaneous fat. The subcutaneous fat had higher levels of saturated fatty acids and lower levels of unsaturated and polyunsaturated fatty acids compared with the intramuscular fat. Although the differences reported were generally small, it would seem that there may be scope to utilise these genetic differences to produce meat with more desirable fatty acid characteristics.
(21-July-2006)

Cafe, L.M., Hearnshaw, H., Hennessy, D.W., Greenwood, P.L. 2006. "Growth and carcass characteristics of Wagyu-sired steers at heavy market weights following slow or rapid growth to weaning". Australian Journal of Experimental Agriculture, 46(7): 951–955

KEYWORDS: backgrounding, beef, cattle, feedlot, marbling, meat

SUMMARY: Two groups of Wagyu × Hereford steers grown slowly (slow preweaning group, n = 14, mean average daily gain = 631 g/day) or rapidly (rapid preweaning group, n = 15, mean average daily gain = 979 g/day) from birth to weaning were backgrounded on improved, temperate pasture to equivalent group liveweights (543 v. 548 kg, s.e. = 8.8 kg), then finished in a feedlot for 120 days. At weaning, the slow preweaning group was 79 kg lighter than the rapid preweaning group. They required an additional 43 days of backgrounding to reach the same feedlot entry weight as the rapid preweaning group. The slow preweaning group grew more rapidly during backgrounding (630 v. 549 g/day, s.e. = 13.7 g/day) but tended to grow more slowly during feedlotting (1798 v. 1982 g/day, s.e. = 74.9 g/day) than their rapid preweaning counterparts, with overall growth rates from weaning to feedlot exit not differing between the 2 groups (rapid 763 g/day v. slow 772 g/day, s.e. = 17.5 g/day). At slaughter, following the feedlot phase, carcass weights of the 2 groups did not differ significantly (rapid 430 kg v. slow 417 kg, s.e. = 7.2 kg). There was a tendency for the steers grown slowly to weaning to have a higher dressing percentage (57.6 v. 56.6%, s.e. = 0.33%), but there were no significant differences in carcass compositional characteristics between the 2 groups. The slow preweaning steers did have a greater eye muscle area than the rapid preweaning steers (106.6 v. 98.9 cm2, s.e. = 1.87) when carcass weight was used as a covariate. These findings demonstrate that cattle grown slowly to weaning have similar composition at slaughter as those grown rapidly during the same period when backgrounded on pasture to the same feedlot entry weight. Furthermore, marbling was not adversely affected by slow growth to weaning.
(21-July-2006)

Rachagani, S., Gupta, I.D., Gupta, N., Gupta, Sc. 2006. "Genotyping of beta-Lactoglobulin gene by PCR-RFLP in Sahiwal and Tharparkar cattle breeds". BMC Genetics, 7:31.

KEYWORDS: Genotyping, beta-Lactoglobulin gene, PCR-RFLP, cattle

SUMMARY: Improvement of efficiency and economic returns is an important goal in dairy farming, as in any agricultural enterprise. The primary goal of dairy industry has been to identify an efficient and economical way of increasing milk production and its constituents without increasing the size of the dairy herd. Selection of animals with desirable genotypes and mating them to produce the next generation has been the basis of livestock improvement and this would continue to remain the same in the coming years. The use of polymorphic genes as detectable molecular markers is a promising alternative to the current methods of trait selection once these genes are proven to be associated with traits of interest in animals. The point mutations in exon IV of bovine &#946;-Lactoglobulin gene determine two allelic variants A and B. These variants were distinguished by Polymerase Chain Reaction and Restriction Fragment Length Polymorphism (PCR-RFLP) analysis in two indigenous Bos indicus breeds viz. Sahiwal and Tharparkar cattle. DNA samples (228 in Sahiwal and 86 in Tharparkar) were analyzed for allelic variants of &#946;-Lactoglobulin gene. Polymorphism was detected by digestion of PCR amplified products with Hae III enzyme, and separation on 12 % non-denaturing gels and resolved by silver staining. The allele B of &#946;-Lactoglobulin occurred at a higher frequency than the allele A in both Sahiwal and Tharparkar breeds. The genotypic frequencies of AA, AB, and BB in Sahiwal and Tharparkar breeds were 0.031, 0.276, 0.693 and 0.023, 0.733, 0.244 respectively. Frequencies of A and B alleles were 0.17 and 0.83, and 0.39 and 0.61 in Sahiwal and Tharparkar breeds respectively. The Chi-square test results (at one degree of freedom at one per cent level) revealed that the Tharparkar population was not in Hardy-Weinberg equilibrium as there was a continuous migration of animals in the herd studied, where as, the results are not significant for the Sahiwal population. Genotype frequencies of AA were the lowest compared to that of BB genotype in Sahiwal cattle while AB genotypes were more frequent in Tharparkar cattle. The frequency of A allele was found to be lower than that of B allele in both the breeds studied. These results further confirm that Bos indicus cattle are predominantly of b-Lactoglobulin B type than Bos taurus breeds.
(21-July-2006)

Cheong, H.S., Yoon, D-H., Kim, L.H., Park, B.L., Choi, Y.H., Chung, E.R., Cho, Y.M., Park, E.W., Cheong, C., Oh, S-J., Yi, S-G., Park, T., Shin, H.D. 2006. "Growth hormone-releasing hormone (GHRH) polymorphisms associated with carcass traits of meat in Korean cattle". BMC Genetics, 7:35. 2156-7-35

KEYWORDS: Growth hormone-releasing hormone, polymorphism, carcass traits, cattle

SUMMARY: Cold carcass weight (CW) and longissimus muscle area (EMA) are the major quantitative traits in beef cattle. In this study, several polymorphisms of growth hormone-releasing hormone (GHRH) gene were found and the association of polymorphisms with carcass traits (CW and EMA) was examined in Korean native cattle (Hanwoo). By direct DNA sequencing in 24 unrelated Korean cattle, 12 single nucleotide polymorphisms were identified within the 9 kb full gene region, including the 1.5 kb promoter region. Among them, six polymorphic sites were selected for genotyping (n = 428) and five marker haplotypes (frequency > 0.1) were identified. Statistical analysis revealed that -4241A>T showed significant associations with CW and EMA (Pcor = 0.03 and 0.05, respectively). In addition, significant association of ht4 with EMA (Pcor = 0.03) was also detected. These findings suggest that polymorphisms in GHRH might be one of the important genetic factors that influence carcass yield in beef cattle. Sequence variation/haplotype information identified in this study would provide valuable information for the production of a commercial line of beef cattle
(21-July-2006)

Armstrong, E., Postiglioni, A., Marinez, A. 2006. "Microsatellite analysis of a sample of Uruguayan Creole bulls (Bos taurus)". Genetic and Molecular Biology, 29(2):267-272.

KEYWORDS: Uruguayan Creole cattle, genetic diversity, microsatellites

SUMMARY: The Uruguayan Creole cattle genetic reserve consists of a herd of about 600 animals (bulls, cows and calves) located in an indigenous habitat of 650 hectares. In a previous study, a random sample from this herd showed high heterozygosity and a Hardy-Weinberg equilibrium for markers of major genes related to milk production. To study its genetic diversity, a sample of bulls (N = 19 out of 23 for the whole herd) were genotyped using the PCR reaction with a set of 17 microsatellite markers. Between two and seven different alleles were identified per microsatellite in a total of 73 alleles. The expected mean heterozygosity (He) per locus was between 0.465 and 0.801, except for microsatellite HEL13 which gave a He value of 0.288. The expected mean heterozygosity was 0.623 and the polymorphic information content (PIC) was between 0.266 for HEL13 and 0.794 for CSSM66. The genetic diversity found in polymorphic markers in the breeding bulls of this Creole cattle population supports previous genetic analyses using major production genes and indicate that further studies should be carried out on this population to provide data of interest to cattle production.
(21-July-2006)

Costa, L.F.S. da, Machado, M.S.N., Oliveira, J.F.C. 2006. "Annexin II mRNA expression in bovine oocytes during follicular development". Genetic and Molecular Biology, 29(2):396-400.

KEYWORDS: bovine oocytes, annexin II, retinol.

SUMMARY: the expression of calcium-dependent phospholipid binding protein annexin-II (Ann-II) messenger RNA (mRNA) during preantral follicle development and in oocytes from antral follicles of different diameters (< 3 mm, 5 to 8 mm and > 8 mm) were investigated. The action of retinol on Ann-II mRNA expression in mature oocytes was also examined. Only oocytes from secondary preantral follicles expressed Ann-II mRNA and at the germinal vesicle stage expression by oocytes from follicles larger than 8 mm was significantly higher (p < 0.05) compared with oocytes from follicles smaller than 3 mm or between 5 and 8 mm. Ann-II mRNA expression by metaphase II oocytes from follicles larger than 8 mm was significantly higher (p < 0.05) than that from oocytes from follicles smaller than 3 mm, with oocytes from both these size-classes showing similar levels of Ann-II mRNA expression as oocytes recovered from 5-8 mm follicles. In the presence of retinol, Ann-II mRNA expression was higher than when retinol was absent (p < 0.05). The data indicate that Ann-II mRNA expression is highest in competent oocytes and that retinol increases Ann-II mRNA and may be involved in the regulation of oocyte competence by decreasing the translation and/or degradation of Ann-II mRNA.
(21-July-2006)

MacNeil, M. D., Mott, T. B. 2006. "Genetic analysis of gain from birth to weaning, milk production, and udder conformation in Line 1 Hereford cattle". Journal of Animal Science, 84:1639-1645

KEYWORDS: genetic correlation, growth, heritability, maternal, udder score

SUMMARY: The objective of this research was to partition phenotypic variation in calf gain from birth to weaning, and milk production measured, by the weigh-suckle-weigh method, and udder score of cows into genetic and nongenetic components. Data were from the Line 1 Hereford population maintained by USDA-ARS at Miles City, MT, and included observations of pre-weaning gain (n = 6,835) from 2,172 dams, milk production (n = 692) from 403 cows, and udder score (n = 1,686) from 622 cows. Data were analyzed using a Gibbs sampler for multiple-trait animal models. Results are reported as means ± SD derived from the posterior distributions of parameter estimates. Mean estimates of the phenotypic variance of preweaning gain, milk production, and udder score were 476.3 kg2, 8.88 kg2, and 1.89 (1 to 9 scale), respectively. Estimates of phenotypic correlations between preweaning gain and milk production, preweaning gain and udder score, and milk production and udder score were 0.37 ± 0.04, – 0.07 ± 0.04, and – 0.09 ± 0.05, respectively. Estimates of heritability for direct and maternal preweaning gain, milk production, and udder score were 0.13 ± 0.03, 0.25 ± 0.04, 0.25 ± 0.06, and 0.23 ± 0.05, respectively. Genetic correlations of milk production with maternal preweaning gain and udder score were estimated as 0.80 ± 0.08 and – 0.36 ± 0.16, respectively. Posterior distributions of the other genetic correlations all contained 0.00 within the respective 90% probability density posterior intervals. Estimates of repeatability of maternal preweaning gain, milk production, and udder score were 0.43 ± 0.03, 0.39 ± 0.05, and 0.34 ± 0.03, respectively. Breeding value for maternal gain from birth to weaning was highly predictive of breeding value for milk production. Direct measurement of milk production to use in genetic improvement may not be justified because it is difficult to measure, and selection based on the breeding value for maternal preweaning gain may be nearly as effective in changing milk production as direct selection. A potentially undesirable consequence of selection to increase milk production is the degradation of udder quality. However, this correlation is not so strong as to preclude simultaneous improvement of milk production and udder quality using appropriate predicted breeding values for each trait.
(21-July-2006)

MacNeil, M. D., Geary, T. W., Perry, G. A., Roberts, A. J. Alexander, L. J. 2006. "Genetic partitioning of variation in ovulatory follicle size and probability of pregnancy in beef cattle". Journal of Animal Science, 84: 1646-1650

KEYWORDS: cattle, fertility, follicle, ovulation

SUMMARY: The objectives of this research were to partition variation in ovulatory follicle size into genetic and nongenetic components and to assess the utility of ovulatory follicle size as an indicator trait associated with reproductive success in beef cattle. Data were collected during the years 2002 to 2005 from 780 beef females that ranged in age from 1 to 12 yr (mean of 2.4 observations per female). Data were analyzed with a multiple trait Gibbs sampler for animal models to make Bayesian inferences from flat priors. A chain of 500,000 Gibbs samples was thinned to every 200th sample to produce a posterior distribution composed of 2,500 samples. Heritability estimates (posterior mean ± SD) were 0.16 ± 0.03 for follicle size and 0.07 ± 0.02 and 0.02 ± 0.01 for pregnancy rate as a trait of the female and service sire, respectively. Posterior means of genetic correlations were all <0.10, with 0.00 contained within the respective 90% probability density posterior intervals. Results indicate that whereas follicle size is of greater heritability than pregnancy rate, its usefulness to improve reproductive rate is greatest as an ancillary phenotype in multiple trait selection.
(21-July-2006)

Keating, A.F., Smith, T.J., Ross, R.P., Cairns, M.T. 2006. "A single nucleotide polymorphism in the bovine β-casein promoter region across different bovine breeds". Journal of Dairy Research, 73: 193-196.

KEYWORDS: β–casein, SNP, bovine.

SUMMARY: The bovine β-casein (CSN2) gene has been shown to span a region of 8•5 kb, containing nine exons and eight intervening introns. The exons range in size from 24 to 498 bp; the introns, however, are much larger and account for 85% of the gene. Twelve genetic variants in the coding sequence of the β-casein gene have previously been reported. The A2 allele of the β-casein gene has been associated with a higher milk production, while the B variant has been associated with an increase in protein content and better cheesemaking properties. The β-casein gene codes for a protein of 209 amino acids with varying regions at codons 67, 106 and 122. The A1 variant differs from A2 at position 67, where a histidine replaces a praline. The β-casein A2 variant has histidine and the A3 variant has glycine at position 106, the β-casein A2 variant has serine at position 122 and the β-casein B variant has arginine at this codon.
(21-July-2006)

VanRaden, P.M., Miller, R.H. 2006. "Effects of Nonadditive Genetic Interactions, Inbreeding, and Recessive Defects on Embryo and Fetal Loss by Seventy Days". Journal of Dairy Science, 89:2716-2721

KEYWORDS: nonreturn rate, recessive defect, inbreeding, dominance

SUMMARY: Lethal recessive genes that cause early embryo loss are difficult to detect. Nonreturn rate at 70 d after first insemination (NR) was evaluated as a trait of the embryo using 1,739,055 first-service records from 1,251 Holstein bulls represented as both service sires and sires of cows. Effects modeled included herd-year-season, parity of cow, sire of cow, service bull, interaction of service bull with sire of cow, and regression on inbreeding of embryo. Variances of service bull and sire of cow were estimated using REML and estimated effects were removed from the data. Interaction variance was estimated from the residuals using the tilde-hat approximation to REML. An additive relationship matrix was used for sire of cow and a dominance relationship matrix for the interaction term. Service bull effects were assumed constant across time and unrelated. For each 10% increase in inbreeding, NR percentage declined by an estimated 1%. A regression of this size could be explained by > 20% of animals carrying defects that cause early embryo loss. Of the total variance, service bull contributed 0.36%; sire of cow, 0.24% (heritability of 1.0%); and interaction, 0.18% (dominance variance of 2.8%). Numbers of records exceeded 500 for 50 bull pair subclasses. Predicted interactions that included effects of inbreeding ranged from – 3.6% to +2.9%, compared with the mean NR of 56%. The largest negative interactions were not caused by known recessive defects. Complex vertebral malformation generally causes loss of pregnancies later in gestation, and few current bulls carry the gene for deficiency of uridine monophosphate synthase. Further study of the families with largest negative interactions could uncover new recessive defects.

Cole, J.B., VanRaden, P.M. 2006. "Genetic Evaluation and Best Prediction of Lactation Persistency". Journal of Dairy Science, 89:2722-2728

KEYWORDS: best prediction, genetic evaluation, persistency

SUMMARY: Cows with high persistency tend to produce less milk than expected at the beginning of lactation and more than expected at the end. Best prediction of persistency was calculated as a function of a trait-specific standard lactation curve and a linear regression of test-day deviations on days in milk. Regression coefficients were deviations from a balance point to make yield and persistency phenotypically uncorrelated. The objectives of this study were to calculate (co)variance components and breeding values for best predictions of persistency of milk (PM), fat (PF), protein (PP), and SCS (PSCS) in Holstein cows. Data included 8,682,138 lactations from 4,375,938 cows calving since 1997, and 39,354 sires were evaluated. Sire estimated breeding values (EBV) for PM, PF, and PP were similar and ranged from –0.70 to 0.75 for PM; EBV for PSCS ranged from –0.37 to 0.28. Regressions of sire EBV on birth year were near zero (<0.003) but positive for PM, PF, and PP, and negative for PSCS. Genetic correlations of PM, PF, and PP with PSCS were moderate and favorable, indicating that increasing SCS decreases yield traits, as expected. Genetic correlations among yield and persistency were low to moderate and ranged from –0.09 (PSCS) to 0.18 (PF). This definition of persistency may be more useful than those used in test-day models, which are often correlated with yield. Routine genetic evaluations for persistency are feasible and may allow for improved predictions of yield traits. As calving intervals increase, persistency may have greater value.
(21-July-2006)

Nauta, W.J., Veerkamp, R.F., Brascamp, E.W., Bovenhuis, H. 2006. "Genotype by Environment Interaction for Milk Production Traits Between Organic and Conventional Dairy Cattle Production in The Netherlands". Journal of Dairy Science, 89:2729-2737

KEYWORDS: genotype by environment interaction, organic dairy production, somatic cell score

SUMMARY: Estimates of genetic parameters for organic dairy farming have not been published previously, and neither is information available on the magnitude of genotype by environment interaction (GxE) between organic and conventional farming. However, organic farming is growing worldwide and basic information about genetic parameters is needed for future breeding strategies for organic dairy farming. The goal of this study was to estimate heritabilities of milk production traits under organic farming conditions and to estimate the magnitude of GxE between organic and conventional dairy farming. For this purpose, production records of first-parity Holstein heifers were used. Heritabilities of milk, fat and protein yield, and somatic cell score (SCS) were higher under organic farming conditions. For percentages of fat and protein, heritabilities of organic and conventional production were very similar. Genetic correlations between preorganic and organic, and organic and conventional milk production were 0.79 and 0.80, respectively. For fat yield, these correlations were 0.86 and 0.88, and for protein yield, these were 0.78 and 0.71, respectively. The findings indicate that moderate GxE was present for yield traits. For percentage of fat and protein and SCS, genetic correlations between organic and conventional and preorganic production were close to unity, indicating that there was no GxE for these traits.
(21-July-2006)

Weller, J. I., Ezra, E., Leitner, G. 2006. "Genetic Analysis of Persistency in the Israeli Holstein Population by the Multitrait Animal Model". Journal of Dairy Science, 89:2738-2746

KEYWORDS: persistency, multitrait animal model, Israeli Holstein, genetic evaluation

SUMMARY: Persistency was defined as the predicted milk production 180 d after peak divided by peak production (in %). Heritability of persistency in a multitrait analysis including parities 1 through 5 increased from 0.16 to 0.27 from first through third parity, and then declined through fifth parity. Genetic correlations for persistency between consecutive parities were all > 0.8. First-parity genetic correlations of the traits included in the Israeli selection index with persistency were all < 0.1, except for fertility and herdlife, which were 0.20 and 0.25; whereas second-parity genetic correlations of persistency with the 3 milk production traits were all > 0.34, and the genetic correlation with fertility was only 0.10. The genetic correlation between second-parity persistency and herdlife was 0.58. Persistency in the Israeli Holstein population was analyzed by the multitrait animal model. The genetic trend since 1985 for the multiparity index was 0.22% persistency/yr, even though there was no direct selection on persistency.
(21-July-2006)

Maltecca, C., Khatib, H., Schutzkus, V.R., Hoffman, P. C., Weigel, K.A. 2006. "Changes in Conception Rate, Calving Performance, and Calf Health and Survival From the Use of Crossbred Jersey x Holstein Sires as Mates for Holstein Dams". Journal of Dairy Science, 89:2747-2754

KEYWORDS: crossbreeding, dairy calf, health, immune function

SUMMARY: Differences in conception rates in matings of Holstein sires or F1 Jersey x Holstein sires to Holstein dams in the University of Wisconsin–Madison experimental herd were evaluated, as were differences in birth weight, dystocia, serum protein, serum IgG, fecal consistency, respiratory disease, and perinatal and pre-weaning mortality among the resulting calves. When mated to randomly chosen, lactating Holstein cows, Holstein sires (n = 74) and crossbred sires (n = 7) did not differ in male fertility. Calves from Holstein sires and multiparous Holstein dams (n = 99) were 1.9 kg heavier than calves from crossbred sires and multiparous Holstein dams (n = 211), leading to greater likelihood (odds ratio of 1.24) of dystocia. Furthermore, calves from crossbred sires and multiparous Holstein dams had higher serum protein and serum IgG levels between 24 and 72 h of age, as well as lower rates of perinatal and preweaning morality than calves from Holstein sires and multiparous or primiparous Holstein dams. Mean fecal consistency scores from birth to 7 d of age and number of days with scours also tended to be lower among calves from crossbred sires, compared with calves from Holstein sires. No differences were observed in the incidence or severity of respiratory disease. Results of this study suggest that introduction of Jersey genes via crossbreeding may lead to a reduction in dystocia and improvements in calf health and survival in Holstein herds. Future studies should address other traits related to dairy farm profitability, including milk composition, female fertility, longevity, feed efficiency, and resistance to infectious and metabolic diseases.
(21-July-2006)

Cienfuegos-Rivas, E.G., Blake, R.W., Oltenacu, P.A., Castillo-Juarez, H. 2006. "Fertility Responses of Mexican Holstein Cows to US Sire Selection". Journal of Dairy Science, 89:2755-2760

KEYWORDS: genotype by environment interaction • milk yield • age at first calving • Mexico

SUMMARY: Genetic relationships between 2 fertility traits and milk production were investigated using mature-equivalent lactation records of 55,162 daughters of 1,339 Holstein sires in Mexico and 499,401 daughters of 663 Holstein sires in the northeastern United States. Data sets contained yields in first and second lactation, age at first calving (AFC), and calving interval (CI). There were 474 US sires in common between countries. A herd-year standard deviation criterion defined nonoverlapping low- ( 1,300 kg) and high- ( 1,600 kg) opportunity Mexican herd environments and a low-opportunity ( 1,024 kg) US environment. Genetic variances for the average Mexican herd (all data) for AFC and CI were 65 and 85% as large as those obtained from half-sisters in the average US herd. Genetic correlations for first-lactation milk in the average US herd and AFC and CI in the average Mexican environment were unfavorable (0.18 and 0.10). Regression coefficients of AFC in Mexican environments on US genetic gain in milk ranged from 2 to 7 d/1,000 kg. However, the favorable predicted response in AFC from genetic gain in milk in Mexican environments, like those in average US herds, ranged from – 4 to – 7 d/1,000 kg (rg = – 0.20). This unequal AFC response may indicate genotype by environment interaction in fitness performance or differential breeding management of high and low yielding Mexican cows. The potential effects of age at first service of breeding females need to be disentangled to accurately assess genetic improvement needs for Mexican Holstein herds.
(21-July-2006)

Picard, B., Jurie, C., Duris, M.P., Renand, G. 2006. "Consequences of selection for higher growth rate on muscle fibre development in cattle". Livestock Science, 102 (1-2): 107-120

KEYWORDS: Muscle hypertophy; Muscle fibre development; Contractile and metabolic properties

SUMMARY: The aim of this study was to analyse the consequences of selection on the development of muscle fibres in the semitendinosus muscle of two groups of Charolais bulls with a high or low muscle growth index. Muscle fibre kinetics were analysed during foetal life (110, 180, 210, 260 days of gestation) and after birth (3 weeks, 9, 15, 19 months). The weight, length and area of muscle were measured. The total number of fibres and muscle fibre area were calculated for each stage. The contractile properties of fibres were revealed by immunohistochemistry. Oxidative capacity of individual fibres was determined on serial sections stained for Succinate Dehydrogenase. Finally, whole muscle metabolic properties were measured on homogenates of muscle with analysis of the activity of Lactate Dehydrogenase (glycolytic) and Isocitrate Dehydrogenase (oxidative). The main results showed muscle hypertrophy in bulls with a high growth potential due to a higher total number of fibres (indicating hyperplasia). From the last trimester of gestation onwards, this is associated with particular contractile and metabolic properties, with mainly a higher proportion of IIX fibres (fast glycolytic). However, the delayed physiological maturity of these bulls induced a delay in the plasticity of muscle fibres after birth. Consequently, the effects of selection on growth rate on muscle properties are not evident at each stage.
(21-July-2006)

Morris, C. A., Amyes, N. C., Cullen, N. G., Hickey, S. M. 2006. "Carcass composition and growth in Angus cattle genetically selected for differences in pubertal traits". New Zealand Journal of Agricultural Research, 49: 1–11

KEYWORDS: Angus; puberty; weight; genetics; correlation; carcass; fat

SUMMARY: A selection experiment to change reproductive traits in Angus cattle was established in New Zealand in 1984/85. Alongside an unselected control line, three lines were set up, selected for increased age at puberty in heifers (AGE+ line), reduced age at puberty in heifers (AGE– line), or increased scrotal circumference (SC line), with the last two lines being merged at the 1992 matings (forming a new AGE– line, with continued heifer puberty selection). The heritability of the direct response (age at puberty) through to 2004 was 0.27 ± 0.04. The purpose of the present study was to investigate correlated responses in carcass composition and growth traits, in response to pubertal selection. Traits measured included weaning, yearling, and breeding-cow weights, carcass weight, dressing percentage, the weights of pericardial, omental and kidney fats, and the percentages of meat, bone, and trimmed fat. The carcass study included selection-line and control animals (n = 185; calf crops born in 1997–2002), and also back-crosses to both lines (n = 294; calf crops born in 2000–02). The divergence in age at puberty in heifers from the AGE+ and AGE– lines was 62 days (16% of the mean). For carcass traits, the only consistent line effects across both the AGE+ and AGE– lines and the back-cross lines were in pericardial fat weights of post-pubertal bulls (P < 0.05). However, where significant line differences in kidney fat weight or fore-quarter fat trim percentage occurred, they were also in the same direction as for pericardial fat (AGE+ animals fatter than AGE– animals). For heifers and steers, none of the line contrasts for fat traits was significant. The selection-line effects for weaning, yearling, and pre-calving mature cow weights (AGE+ minus AGE– means) were 2.5 ± 2.1, –7.3 ± 3.0 (P < 0.05), and 8.2 ± 3.7 kg (P < 0.05), 1.5, –2.7, and 1.8% of their respective means. The interpretation of these results was that earlier sexual maturity in heifers (AGE– line) was associated with a steeper juvenile growth curve through puberty, but ultimately the cows were lighter than in the AGE+ line and not different in fatness. Earlier sexual maturity in bulls was also associated with a steeper growth curve, but there was the suggestion from some fatness traits that the AGE– line were leaner than the AGE+ line when compared at the same age.
(21-July-2006)

Larson, J.H., Kumar, C.G., Everts, R.E., Green, C.A., van der Wind, A.E., Band, M.R., Lewin, H.A. 2006. "Discovery of eight novel divergent homologs expressed in cattle placenta". Physiological Genomics, 25:405-413

KEYWORDS: molecular evolution, bovine genome, comparative genomics

SUMMARY: Ten divergent homologs were identified using a subtractive bioinformatic analysis of 12,614 cattle placenta expressed sequence tags followed by comparative, evolutionary, and gene expression studies. Among the 10 divergent homologs, 8 have not been identified previously. These were named as follows: cattle cerebrum and skeletal muscle-specific transcript 1 (CSSMST1), cattle intestine-specific transcript 1 (CIST1), hepatitis A virus cellular receptor 1 amino-terminal domain-containing protein (HAVCRNDP), prolactin-related proteins 8, 9, and 11 (PRP8, PRP9, and PRP11, respectively) and secreted and transmembrane protein 1A and 1B (SECTM1A and SECTM1B, respectively). In addition, two previously known divergent genes were identified, trophoblast Kunitz domain protein 1 (TKDP1) and a new splice variant of TKDP4. Nucleotide substitution analysis provided evidence for positive selection in members of the PRP gene family, SECTM1A and SECTM1B. Gene expression profiles, motif predictions, and annotations of homologous sequences indicate immunological and reproductive functions of the divergent homologs. The genes identified in this study are thus of evolutionary and physiological importance and may have a role in placental adaptations.
(21-July-2006)

Fürbass, R., Winter, A., Fries, R., Kühn, C. 2006. "Alleles of the bovine DGAT1 variable number of tandem repeat associated with a milk fat QTL at chromosome 14 can stimulate gene expression". Physiological Genomics, 25:116-120

KEYWORDS: DGAT1 promoter polymorphism, causal mutation, transcription factor Sp1, reporter gene expression

SUMMARY: A quantitative trait locus (QTL) affecting milk fat percentage has been mapped to the centromeric end of the bovine chromosome 14 (BTA14). This genomic area includes the DGAT1 gene, which encodes acyl-CoA:diacylglycerol acyltransferase 1, the key enzyme of triglyceride biosynthesis. Genetic and biochemical studies led to the identification of the nonconservative DGAT1-K232A polymorphism as a causal mutation for the QTL. In addition to this, another polymorphism in the 5'-regulatory region of this gene, the DGAT1 variable number of tandem repeat (VNTR), also showed a strong association with milk fat percentage. This promoter VNTR polymorphism affects the number of potential Sp1 binding sites and therefore might have an impact on DGAT1 expression and also milk fat content. Hence, the DGAT1 VNTR polymorphism might be another causal mutation for the BTA14 QTL. However, evidence for Sp1 binding to this polymorphic site and for the capability of DGAT1 VNTR alleles to stimulate gene expression was lacking. In the current work Sp1-VNTR interactions were analyzed by EMSA. In addition, effects of DGAT1 VNTR alleles on gene expression were measured with reporter gene analyses. Conclusions from the results are that 1) the DGAT1 VNTR sequence is indeed a target for Sp1 binding, 2) DGAT1 VNTR alleles can stimulate gene expression in vitro and probably in vivo as well, and 3) although the stimulating effects of the different DGAT1 VNTR alleles did not show significant differences in vitro, their effects on transcription might be different in the chromatin context existing in vivo.
(21-July-2006)

Falcao, A.J. da S., Martins, E.N., Costa, C.N. 2006. "An evaluation of heteroscedasticity of variances of milk yield of Holstein cattle in different states using Bayesian inference via Gibbs sampler". Revista Brasileira de Zootecnia, 35(2): 405-414.

KEYWORDS: Bayesian inference; convergence criterion; heritability; variance components; genotype × environment interaction.

SUMMARY: Adjusted for 305 days milk yield records of Holstein cows calving from 1980 to 1993 in the states of MG, SP, PR, SC, and RS were used to investigate heterogeneity of variance and to evaluate the genotype by environment interaction. Milk production from each State was considered as a different trait and variances were assumed heterogeneous. Milk production was also analyzed using a single-trait model assuming homogeneity of variance. (Co)variance components and genetic parameters were estimated by Bayesian inference, via Gibbs sampler (GS), using a model which included season of calving, genetic group, herd-year of calving and parity as fixed effects and animal additive genetic, permanent environmental and residual as random effects. Convergence of the GS chain to the stationary distribution was diagnosed using the method described by Heidelberg & Welch (1983). The posterior precision of the variance components and the heritability were high in the single-trait analysis. Posterior mean and standard deviation (SD) of heritability of milk yield were 0,278±0,012. For the multiple-trait analysis, posterior precisions of the (co)variance components were larger for SP and PR states. Posterior means and standard errors of heritability for MG, SP, PR, SC, and RS were 0.280±0.021, 0.233±0.015, 0.280±0.012, 0.393±0.026, and 0.382±0.022, respectively. Genetic correlations for milk yield between the five states were very low and ranged from 0.070 to 0.364, suggesting the presence of genotype by environment interaction. Differences in genetic and residual variances of milk yield among the states indicate it would be necessary to account for heterogeneous variances in genetic evaluations.
(21-July-2006)

Magalhaes, H.R., El Faro, L., Cardoso, V.L. 2006. "Effects of environmental factors on somatic cell count and reduction of milk yield on Holstein cows". Revista Brasileira de Zootecnia, 35(2): 415-421.

KEYWORDS: dairy cattle; mastitis; milk yield; somatic cells.

SUMMARY: Cumulative milk yield at 305 days (MY-305) and somatic cell count (SCC) from the first to the fifth lactation of Holstein cows were analyzed in this study. Somatic cell count was logarithmically transformed to somatic cell score (SCS) that was then included in the model not only as a dependent but also as an independent variable. Year, season, and parity order all significantly affected the average SCS in this study. Data of the effect of SCS on milk yield showed significant losses on MY-305 because of the observed negative linear relationship between these two variables. Somatic cell score affected differently MY-305 from different parity orders with greater effect after the 3rd parity. Although clinical mastitis seems to cause greater economic losses, prevention and control of sub-clinical mastitis deserve more attention due to its greater prevalence leading to significant reduction on herd productivity.
(21-July-2006)

Ruas, J.R.M., Brandao, F.Z., Silva Filho, J.M. da. 2006. "Effect of milking frequency on production of crossbred holstein-zebu cows". Revista Brasileira de Zootecnia, 35(2):428-434.

KEYWORDS: calf weight; crossbred cows; daily milking; milk yield; weight gain.

SUMMARY: This trial was conducted to study the effects of daily milking frequency on milk yield, duration of lactation, incidence of mastitis, and calves body weight gain. Sixty-three crossbred Holstein-Zebu cows were equally and randomly assigned to three experimental groups according to the frequency of daily milkings as follows: once a day milking, twice a day milking, or alternating once or twice a day milking every 14 days. The duration of lactation, mammary gland health, and calf production did not differ among treatments in this study. However, cows milked twice a day yielded 24.54% more milk per lactation (699.9 kg) compared to the other milking regimes.
(21-July-2006)

Özluturk, A., Yanar, M., Tuzemen, N., Kopuzlu, S. 2006. "Calving and Preweaning Growth Performance Traits of Calves Sired by Charolais, Simmental and Eastern Anatolian Red Bulls". Turkish Journal of Veterinary and Animal Sciences, 30: 257-263.

KEYWORDS: Calf, breeds of sire, growth traits, beef cattle, calving traits

SUMMARY: Charolais (C)-, Simmental (S)-, and Eastern Anatolian Red (EAR)-sired calves born in 2 locations in Eastern Anatolia were compared in terms of calving traits and preweaning growth characteristics. Breed of sire effects were significant (P < 0.01) for birth weight, 205-day weaning weight, average daily weight gain from birth to weaning, and some body measurements at birth. S- and C-sired calves were heavier at birth and larger for most body measurements at birth than EAR-sired calves. The C- and S-sired calves also had higher 205-day weight than the EAR-sired calves. Although the level of calving difficulty was higher in the S and C crosses, the differences were not statistically significant. Male calves had significantly (P < 0.01) heavier birth and 205-day weights, higher preweaning average daily gain and greater body measurements (e.g., height at withers, heart girth and cannon bone girth) than females. Location differences were also significant (P < 0.01) for survival rate from birth to weaning, preweaning growth rate and 205-day weight. In conclusion, although C- and S-sired calves performed similarly for most traits, all parameters of the preweaning growth were higher in calves sired by S and C bulls than in calves sired by EAR bulls. Therefore, both C and S could be considered as sire breeds for crossbreeding programs to be implemented in Eastern Anatolia, since these breeds did not cause an adverse influence on the calving and growth traits of the crossbred calves.
(21-July-2006)

Odani, M., Narita, A., Watanabe, T., Yokouchi, K., Sugimoto, Y., Fujita, T., Oguni, T., Matsumoto, M., Sasaki, Y. 2006. "Genome-wide linkage disequilibrium in two Japanese beef cattle breeds". Animal Genetics, 37 (2): 139-144.

KEYWORDS: Beef cattle, fine-mapping, linkage disequilibrium, selection

SUMMARY: There is little knowledge about the degree of linkage disequilibrium (LD) in beef cattle. This study aims to perform a genome-wide search for LD in Japanese Black and Japanese Brown beef cattle and to compare the level of LD between these two breeds. Parameter D' (the LD coefficient) was used as a measure of LD, and LD was tested for significance of allelic associations between syntenic and between non-syntenic marker pairs. Effects of breed, chromosome, genetic map distance and their interactions with D' were tested based on least squares analyses. Both breeds showed high levels of LD, which ranged over several tens of cM and declined as the marker distance increased for syntenic marker pairs. A rapid decline of the D' value was observed between markers that were spaced 5 and 20 cM apart. LD was significant in most cases for marker pairs <40 cM apart but was not significant between non-syntenic loci. The pattern of LD found in these two breeds was similar to that previously published for dairy cattle. The D' value between breeds was not significantly different (P > 0.05), but the interaction between breed and chromosome was highly significant (P < 0.001). Genetic selection seems to have caused the heterogeneity of the D' values among chromosomes within breed. These results indicate that LD mapping is a useful tool for fine-mapping quantitative trait loci of economically important traits in Japanese beef cattle.
(6-June-2006)
 

Childers, C. P., Newkirk, H. L., Honeycutt, D. A., Ramlachan, N., Muzney, D. M., Sodergren, E., Gibbs, R. A., Weinstock, G. M., Womack, J. E., Skow, L. C. 2006. "Comparative analysis of the bovine MHC class IIb sequence identifies inversion breakpoints and three unexpected genes". Animal Genetics, 37 (2): 121-129.

KEYWORDS: BoLA IIb, cow, genomic sequence, major histocompatibility complex

SUMMARY: The bovine major histocompatibility complex (MHC) or BoLA is organized differently from typical mammalian MHCs in that a large portion of the class II region, called class IIb, has been transposed to a position near the centromere on bovine chromosome 23. Gene mapping indicated that the rearrangement resulted from a single inversion, but the boundaries and gene content of the inverted segment have not been fully determined. The genomic sequence of BoLA IIb was reproted. Comparative sequence analysis with the human MHC revealed that the proximal inversion breakpoint occurred approximately 2.5 kb from the 3' end of the glutamate-cysteine ligase, catalytic subunit (GCLC) locus and that the distal breakpoint occurred about 2 kb from the 5' end from a divergent class IIDRβ-like sequence designated DSB. Gene content, order and orientation of BoLA IIb are consistent with the single inversion hypothesis when compared with the corresponding region of the human class II MHC (HLA class II). Differences with HLA include the presence of a single histone H2B gene located between the proteasome subunit, beta type, 9 (PSMB9) and DMB loci and a duplicated TAP2 with a variant splice site. BoLA IIb spans approximately 450 kb DNA, with 20 apparently intact genes and no obvious pseudogenes. The region contains 227 simple sequence repeats (SSRs) and approximately 167 kb of retroviral-related repetitive DNA. Nineteen of the 20 genes identified in silico are supported by bovine EST data indicating that the functional gene content of BoLA IIb has not been diminished because it has been transposed from the remainder of BoLA genes.
(6-June-2006)
 

Kahi, A. K., Hirooka, H. 2006. "Economic efficiency of Japanese Black cattle selection schemes utilizing crossbreeding with the Holstein breed". Animal Science Journal, 77 (2): 178-187.

KEYWORDS: Carcass traits, crossbreeding, Holstein, Japanese Black cattle, selection schemes

SUMMARY: The economic efficiency of Japanese Black (JB) cattle selection schemes utilizing crossbreeding with the Holstein (H) breed was evaluated in the context of maximizing profitability. Selection schemes were defined that differed in the records available for use as selection criteria. The selection schemes were assessed based on profitability per cow in the JB cattle population. Within each selection scheme, two terminal crossbreeding systems were considered: two-way crossbreeding without backcrossing (F1 system) and two-way crossbreeding with backcrossing (F1 cross system). The impact on profitability of varying number of sires selected per year and the proportion of H cows that were inseminated by JB semen and of F1 females that are retained for replacement was examined for all selection schemes. Utilizing crossbreeding with the H breed was less profitable than purebreeding of the JB. Profitability was higher in the F1 system than in the F1 cross system in all selection schemes. Profitability was influenced more by changes in the number of sires selected per year than by the proportion H cows that were inseminated by JB semen and of F1 females that were retained for replacement. Implications of these results for the JB breeding program are discussed.
(6-June-2006)
 

Rewe, T. O., Indetie, D., Ojango, J. M. K., Kahi, A.K. 2006. "Breeding objectives for the Boran breed in Kenya: Model development and application to pasture-based production systems". Animal Science Journal, 77 (2): 163-177.

KEYWORDS: Beef cattle, Boran, breeding objective, profit model, tropics

SUMMARY: Bio-economic profit models were developed and applied to evaluate biological and economic variables that characterize production systems utilizing the Boran breed. Production systems were described according to their sale age (24 months short-fed or 36 months long-fed), levels of input (low, medium or high) and final goal (beef or dual purpose) representing practical circumstances that exist in the various beef cattle farms in Kenya. The input variables were classified into production and economic variables. The outputs from the profit models included revenue, costs and feed intake of cows, heifers and steers in the different production systems. These models can be used to simulate changes in production and marketing circumstances. The biological relationships and assumptions in the model are general and flexible and can therefore be applied to a wide range of beef cattle production circumstances by changing the input variables. In addition, by modifying the herd dynamics and management variables this model may be applied in Kenya or other countries to production systems that utilize indigenous cattle genetic resources or their crosses with Bos taurus breeds
(6-June-2006)
 

Takeshima, S-N., Aida, Y. 2006. "Structure, function and disease susceptibility of the bovine major histocompatibility complex". Animal Science Journal, 77 (2): 138-150.

KEYWORDS: bovine leukocyte antigen, disease resistance, function, genetics, polymorphism.

SUMMARY: The major histocompatibility complex (MHC) of cattle is known as the bovine leukocyte antigen (BoLA) and is located on chromosome 23. BoLA has been linked to variation in resistance to disease including bovine leukemia virus-induced lymphoma and mastitis. Moreover, BoLA appears to influence other traits such as milk yield, growth and reproduction, which are not often measured in humans, and variations in individual immune response to antigen. The BoLA appears to be organized in a similar way to the MHC region in humans, but there are notable differences. A major rearrangement within the class II region has led to the division of the BoLA into two distinct subregions of chromosome 23 separated by about a third of the chromosome's length. The class IIa subregion contains functionally expressed DR and DQ genes, while the class IIb subregion contains the genes of undefined status such as DYA, DYB, DMA, DMB, DOB, DOA, TAP1, TAP2, LAP2 and LMP7. In addition, one pair of human class II genes (DP) does not appear to have an equivalent in cattle, and there is one pair of DY genes that seem to be found only cattle, sheep and goats. In humans, three classical, polymorphic class I genes (HLA-A, -B and -C ) are each present on all haplotypes. However, in cattle, none of the four (or more) classical class-I genes identified are consistently expressed, and haplotypes differ from one to another in both the gene number and composition. These variations in both class I and II are likely to play an important role in cattle immune responses. This review summarizes current knowledge of the structural and functional features and disease association of BoLA genes.
(6-June-2006)
 

Teixeira, C., Oliveira, D., Quirino, C. 2006.. "Double muscling II.– Genetic determination". Archivos Latinoamericanos de Producción Animal [Online] 14:1. Available: http://www.alpa.org.ve/ojs/viewarticle.php?id=472

KEYWORDS: Double muscling, myostatin, mutation

SUMMARY: Mutations in the myostatin gene that increase muscle mass, characterize double muscling or muscular hypertrophy phenotype in some cattle breeds. Despite of some restrictions related to calving easy, carcass of these animals are considered superior, resulting in higher meat yield, higher proportion of expensive meat cuts and lean and tender meat, and have been used in production systems worldwide. The possibility to identify the carriers of the mutation has been decisive in meat production systems. The mutation was identified in others species of economic interest, such as sheep, demanding new researches and strategies to improve the production systems.
(6-June-2006)
 

Gonzalez-Stagnaro, C., Goicochea Llaque, J., Rodríguez-Urbina, M., Madrid Bury, N., González Villalobos, D. 2006. "Introduction to breeding in crossbred dual purpose heifers". Archivos Latinoamericanos de Producción Animal [Online] 14:1. Available:
http://www.alpa.org.ve/ojs/viewarticle.php?id=344

KEYWORDS: crossbred cattle, weight at service, age at service

SUMMARY: This study evaluated 21,667 observations of age (EI) and weight (PI) of introduction to service in heifers from 47 dual purpose bovine herds, located in four areas of dry and humid tropical forest environments. Effects studied were those of geographic area (Laberinto, Perija, Costa Oriental and Sur del Lago); management system: traditional (ST) and improved (SM); breed predominance (Holstein, Brown Swiss, Brahman and Carora); season of birth and of introduction to service; birth weight (PN); and weaning age (ED) and weight (PD). Mean EI was 30.9 ± 5.9 m and was earlier (P < 0.001) in Laberinto and Perija than in the other regions, in SM than ST (27.3 ± 02 vs.31.6 ± 0.01 m), and in Brown Swiss and Brahman than in Holsteins (32.0 ± 01 m). Mean PI was 353.3 ± 31.9 kg and was heavier (P<0.001) in Laberinto to (383.4 ± 1.5 kg), in SM than ST (364.6± 1.0 vs. 349.7 ± 0.5 kg), and Holstein and Brown Swiss (354.3 ± 0.7 and 357.6 ± 1.2 kg). EI was related to PI and dependent on daily weight gain (GDP); 48% of the heifers had GDP of 251 to 350 g/d an only 9.2% gained > 350 g/d. A GDP of > 350 g/d resulted in earliest EI (24.4 ± 0.4 m) and heaviest PI (375.8 ± 1.8 kg). Birth and weaning in dry season delayed EI. Lower EI and higher PI during rainy season were related to grazing conditions. At ED of < 10 m or > 10 m, EI increased (29.2 ± 0.4 to 34.6 ± 0.4 m) and PI decreased (366.2 ± 2.0 to 358.6 ± 2.0 kg); while in heifers with PD < 180 and > 180 kg, EI was 29.9 ± 0.2 and 27.8 ± 0.2 m, and PI was 353.5 ± 0.9 and 359.1 ± 1.1 kg (P<0.001). Adequate feeding management improved EI and PI results.
(6-June-2006)
 

Colditz, I. G. , Watson, D. L., Kilgour, R., Ferguson, D. M., Prideaux, C., Ruby, J., Kirkland, P. D., Sullivan, K. 2006. "Impact of animal health and welfare research within the CRC for Cattle and Beef Quality on Australian beef production". Australian Journal of Experimental Agriculture, 46(2): 233–244.

KEYWORDS: Animal Health, Welfare, beef quality

SUMMARY: Research within the health and welfare program of the Cooperative Research Centre for Cattle and Beef Quality has delivered important improvements to the Australian cattle industry. Vaccines to assist with the control of bovine respiratory disease were developed and commercialised from Australian isolates of Mannheimia haemolytica and pestivirus (mucosal disease). Understanding of the benefits of weaning cattle by confinement and hand feeding in yards (yard weaning) has been consolidated, and yard weaning has been adopted as ‘best practice’ for cattle production in the temperate zones of Australia. The importance of good temperament for improved growth rates and reduced morbidity during feedlot finishing, and for adaptation to stressors such as road transport, has been demonstrated. In response to this knowledge, industry is increasingly measuring flight time for use in breeding programs and feedlot management. The risk to meat quality of stressors such as mixing unfamiliar cattle in the weeks preceding slaughter or acute stress in the last 15 min before slaughter has been described. Adoption of these findings through Quality Assurance schemes will assist in assurance for the community and for export markets of the welfare standards of the Australian cattle and beef industry. This review provides details of the experiments that led to these achievements and to some improved understandings of temperament and behaviour of beef cattle.
(6-June-2006)
 

Pitchford, W. S., Mirzaei, H. M., Deland, M. P. B., Afolayan, R. A., Rutley, D. L. Verbyla, A. P. 2006. "Variance components for birth and carcass traits of crossbred cattle". Australian Journal of Experimental Agriculture, 46(2): 225–231.

KEYWORDS: beef cattle, birth weight, carcass quality, covariance, heritability, survival

SUMMARY: During a 4-year period (1994–97) of the Australian ‘Southern Crossbreeding Project’, mature Hereford cows (n = 637) were mated to 97 sires from 7 breeds (Jersey, Wagyu, Angus, Hereford, South Devon, Limousin and Belgian Blue), resulting in 1334 calves. Heifers were slaughtered at around 16 months and steers at 23 months. The objective of the study was to quantify between- and within-breed genetic variation for numerous production and quality traits in a southern-Australian production system. Calf survival, birth weight and carcass production traits (carcass weight, fat depth, loin eye area, intramuscular fat) were obtained from these cattle. The carcass traits were loge-transformed because of a scale effect on the variance. Data were analysed using multi-variate animal models containing fixed effects of sex with random effects of management group, sire breed and animal. In addition, birth month and age of dam were included as fixed effects for birth weight. Covariances between survival and other traits could not be estimated from the multi-variate model so they were estimated from a series of bi-variate models. On average, management group and sire breed accounted for similar proportions of variance. Heritability ranged from 0.14 (survival), 0.17 (intramuscular fat), 0.28 (loin eye area), 0.29 (P8 fat depth), 0.31 (birth weight) to 0.50 (carcass weight). In general, environmental (management and residual) correlations between meat (carcass weight and loin eye area) and fat traits (fat depth and intramuscular fat) were positive, but the genetic correlations (both between and within breed) were negative. Management and genetic (co)variation has been quantified and can facilitate production of calves with carcasses suitable for specific market requirements.
(6-June-2006)
 

Corbet, N. J., Shepherd, R. K., Burrow, H. M., Prayaga, K. C., van der Westhuizen, J., Bosman, D.J. 2006. "Evaluation of Bonsmara and Belmont Red cattle breeds in South Africa. 2. Genetic parameters for growth and fertility". Australian Journal of Experimental Agriculture, 46(2): 213–223

KEYWORDS: genetic correlation, heritability, maternal effects

SUMMARY: Genetic parameters were estimated for growth and fertility indicator traits in a South African beef cattle population. Measurements on 5601 pedigreed progeny of 96 Bonsmara sires, 18 Belmont Red sires and 20 Bonsmara × Belmont Red cross sires were recorded over 19 years in 4 diverse climatic regions of South Africa. Growth traits were measured on growing stock from birth to 18 months at pasture. Cow weights were measured at calving and weaning. Age at first calving, and repeated measurements of calving day and calving interval were recorded on 1993 breeding females as indicators of reproductive performance. The traits were analysed using univariate and bivariate animal models with maternal effects fitted.
Direct heritability of growth traits (0.11–0.42) and female fertility traits (0.02–0.13) suggested that genetic progress could be made by selection for some traits. Genetic correlations between growth and fertility traits were variable (–0.47–0.85) and indicated that multi-trait selection would be the best method of dealing with multidirectional forces on productivity traits. Genetic correlations between direct and maternal effects on liveweight traits were mostly negative indicating that genetic improvement of traits with strong maternal influence, such as weaning weight, would be complicated and supported the use of post-weaning weights with less maternal influence as selection criteria to improve the direct additive component of growth. The genetic parameter estimates provide useful reference values for estimation of breeding values in a proposed combined-breed genetic evaluation program.
(6-June-2006)
 

Corbet, N. J., Shepherd, R. K., Burrow, H. M., van der Westhuizen, J., Strydom, P. E. Bosman, D.J. 2006. "Evaluation of Bonsmara and Belmont Red cattle breeds in South Africa. 1. Productive performance". Australian Journal of Experimental Agriculture, 46(2): 199–212.

KEYWORDS: adaptability, breed comparison, fertility, growth.

SUMMARY: The productive performance of progeny by Bonsmara and Belmont Red sires was compared in contemporarily reared groups in South Africa. Measurements on 4279 pedigreed progeny of 96 Bonsmara sires and 18 Belmont Red sires were recorded over 15 years in 4 diverse climatic regions of South Africa. Growth traits were measured on growing stock from birth to 18 months at pasture. Weight gain, feed conversion rate, frame size, scrotal circumference and visually assessed ‘functional efficiency’ scores were recorded on male progeny fed high protein rations. Carcass traits were measured on a subset of the male progeny. Age at first calving, and repeated measurements of calving date and calving interval were recorded on breeding females as indicators of reproductive performance. Tick counts were made on males and females across a range of ages during times of heavy field infestation.
There were differences in progeny performance for some traits. Bonsmara sired animals generally scored higher than Belmont Red progeny for functional efficiency. Belmont Red sired calves were lighter at birth (35.9 v. 37.3; P0.05) and cows by Belmont Red sires had a shorter average calving interval (440 v. 455; P<0.05). Sire breed by region interaction was not important. The differences in scored and measured traits generally reflected differences in selection policies adopted by the breed societies. Variation in growth and fertility traits due to sire was greater than variation due to breed and demonstrated the potential for identifying superior individuals. The performance of the sire breeds for the range of traits and environments studied advocated that selected Bonsmara and Belmont Red animals from South African herds would be suitable for inclusion in breeding programs in Australian Belmont Red herds.
(6-June-2006)
 

Hammond, K. 2006. "Breeding strategies for the development of the Australian beef industry: an overview". Australian Journal of Experimental Agriculture, 46(2): 183–198

KEYWORDS: adaptive fitness, artificial insemination, Beef Cooperative Research Centre (CRC), breeding, BREEDOBJECT, BREEDPLAN, carcass quality and yield, cattle, extension, feed intake, genetic improvement, genotype × environment interaction (GEI), management groups, production systems, progeny testing, value-added marketing.

SUMMARY: Strategic directions for the period 2010 to 2020 and research and development needs are considered for the Australian Beef Industry from the breeding sector’s perspective. These are related to the way major technologies are developed for an industry, the current status and likely trends in market development and appropriation of benefits to the consumer, processor, commercial beef producer and breeding sectors. The primary strategic needs identified are: (i) understand the functional biology for the major production environments (supply chain packages), (ii) accelerate the speed of genetic improvement for production environment breeding goals based on commercial sector profitability and the dissemination of superior genetic material to this sector, and (iii) retain and develop the Beef Cooperative Research Centre concept over the period. Tactics for realising each strategy are considered. Rigorously designed industry-level studies based on a genotype × environment interaction approach, involving all major production environments and breeds, have an important role to play, as do the serial development of measuring equipment and procedures for carcass quality and yield, body maintenance, disease management and maternal performance. Information and communication, molecular genetics and artificial insemination technologies, along with formal progeny testing and an extended BREEDPLAN system, will be increasingly used by the breeding as well as commercial industry sectors to more consistently meet particular market demands. Carefully executed progeny testing is a pragmatic and necessary breeding approach for the period, serving a number of important purposes. The beef industry as a whole will need to take more responsibility for its genetic improvement element by: managing the appropriation of benefits across sectors, developing an increasingly effective system of value-based marketing and, for each sector and production environment, a more appropriate program of capacity building. The industry could now usefully consider the further development of its activity to address these longer-term strategic needs.
(6-June-2006)
 

Lehnert, S. A., Wang, Y. H., Tan, S. H., Reverter, A. 2006. "Gene expression-based approaches to beef quality research". Australian Journal of Experimental Agriculture, 46(2): 165–172

KEYWORDS: Gene expression, beef quality

SUMMARY: Advances in mammalian genomics have permitted the application of gene expression profiling approaches to gene discovery for meat quality traits in cattle. The first custom cDNA microarray based on the transcriptome of bovine muscle and fat tissue was developed and applied to animal experimentation and cell culture experimentation between 1999 and 2005. Complementary DNA microarray tools for beef quality research were developed in parallel with bioinformatics tools that permit the analysis of microarray data obtained from complex experimental designs commonly encountered in large animal research. In addition, tools were designed to link gene expression data with gene function in the bovine, such as in vitro models of bovine adipogenesis and bioinformatics tools to map gene networks from expression data. The application of these genomics tools to the study of beef quality has yielded novel knowledge of genes and molecules involved in the processes of intramuscular adipogenesis and protein turnover. This review summarises the current state of knowledge and important lessons derived from bovine genomics initiatives in Australia and around the world.
(6-June-2006)
 

Drinkwater, R. D., Li, Y., Lenane, I., Davis, G. P., Shorthose, R., Harrison, B. E., Richardson, K., Ferguson, D., Stevenson, R., Renaud, J., Loxton, I., Hawken, R. J., Thomas, M. B., Newman, S., Hetzel, D. J. S., Barendse, W. 2006. "Detecting quantitative trait loci affecting beef tenderness on bovine chromosome 7 near calpastatin and lysyl oxidase". Australian Journal of Experimental Agriculture, 46(2): 159–164.

KEYWORDS: Quantitative trait loci, beef tederness, chromosome 7

SUMMARY: From a study of 3 large half-sib families of cattle, linkage between DNA polymorphisms on bovine chromosome 7 and meat tenderness was described. Quantitative trait loci (QTL) for Longissimus lumborum peak force (LLPF) and Semitendonosis adhesion (STADH) were located to this map of DNA markers, which includes the calpastatin (CAST) and lysyl oxidase (LOX) genes. The LLPF QTL has a maximum lodscore of 4.9 and allele substitution of approximately 0.80 of a phenotypic standard deviation, and the peak is located over the CAST gene. The STADH QTL has a maximum lodscore of 3.5 and an allele substitution of approximately 0.37 of a phenotypic standard deviation, and the peak is located over the LOX gene. This suggests 2 separate likelihood peaks on the chromosome. Further analyses of meat tenderness measures in the Longissimus lumborum, LLPF and LL compression (LLC), in which outlier individuals or kill groups are removed, demonstrate large shifts in the location of LLPF QTL, as well as confirming that there are indeed 2 QTL on bovine chromosome 7. These components of tenderness, myofibrillar and connective tissue are detected by both measurements in this muscle.
(6-June-2006)
 

Curi, R.A., Palmieri, D. A., Suguisawa, L. 2006. "Growth and carcass traits associated with GH1/Alu I and POU1F1/Hinf I gene polymorphisms in Zebu and crossbred beef cattle". Genetic and Molecular Biology, 29: 56-61.

KEYWORDS: beef cattle, polymorphisms, candidate gene, growth, carcass.

SUMMARY: The objectives of the present study were to estimate the allele and genotype frequencies of the GH1/Alu I and POU1F1/Hinf I polymorphisms in beef cattle belonging to different genetic groups and to determine the effects of these polymorphisms on growth and carcass traits in cattle submitted to feedlot management, an intensive production model. Genotyping was performed on 384 animals, including 79 Nellore, 30 Canchim (5/8 Charolais + 3/8 Zebu), 30 Simmental x Nellore crossbred and 245 Angus x Nellore crossbred cattle. Body weight, weight gain, dressing percentage, Longissimus dorsi area and backfat thickness were fitted using the General Linear Model (GLM) procedure of the SAS program and the least square means of the genotypes were compared using the F test. The results showed significant associations between the LL genotype of the GH1/Alu I polymorphism and higher weight gain and body weight at slaughter (p < 0.05). The POU1F1/Hinf I polymorphism did not have any effect on the growth and carcass traits analyzed.
(6-June-2006)
 

Golik, M., Cohen-Zinder, M., Loor, J. J., Drackley, J.K., Band, M.R., Lewin, H.A., Weller, J.I., Ron, M., Seroussi, E. 2006. "Accelerated expansion of group IID-like phospholipase A2 genes in Bos taurus". Genomics. 87 (4): 527-533.

KEYWORDS: Phospholipase A2; Genes Duplicate; Immunity Natural; Cattle

SUMMARY: Low-molecular-weight, calcium-dependent phospholipase A2 genes (PLA2s) that belong to the secreted type of PLA2s are clustered within a syntenic group on human 1p35–p36 and mouse 4qD3. Trace files available from the Whole Genome Sequencing (WGS) Project, obtaining an 86-kb contig with three tandem PLA2G2D duplications in the Hereford strain were reassembled. Mate-pair data were used to monitor the assembly and to exclude chimeric clones, demonstrating that the current WGS data may be assembled even in a highly repetitive region with a coverage exceeding fivefold. The genomic structure indicated that most of the PLA2G2D transcripts are formed by four exons. Two alternative first exons were present in all duplications. In two duplications insertions of satellite DNA in the third intron created a novel exon that gave rise to a two-exon product. Linkage and comparative mapping placed the bovine PLA2G2 locus on BTA2, indicating that it evolved from an ancestral PLA2G2D locus common to human, cattle, and rodents. Bovine PLA2G2D variants were capable of encoding 147-amino-acid polypeptides that consisted of putative signal peptide and metal-binding domains. Cysteine residues were conserved in positions analogous to those forming the seven disulfide bonds characteristic of PLA2G2 genes. Quantitative PCR analysis of bovine PLA2G2D transcripts indicated that their expression levels varied between the dry period and lactation in the mammary gland samples and that their expression was polymorphic in liver tissue. The recent burst of duplication and divergence of the bovine PLA2G2D genes and their polymorphic nature are typical of innate immune response genes.
(6-June-2006)
 

Harder, B., Bennewitz, J., Reinsch, N., Thaller, G., Thomsen, H., Kühn, C., Schwerin, M., Erhardt, G., Förster, M., Reinhardt, F., Kalm, E. 2006. "Mapping of quantitative trait loci for lactation persistency traits in German Holstein dairy cattle". Journal of Animal Breeding and Genetics, 123 (2): 89-96.

KEYWORDS: Quantitative trait loci, persistency, German Holstein, dairy cattle.

SUMMARY: A whole genome scan to map quantitative trait loci (QTL) for persistency of milk yield (PMY), persistency of fat yield (PFY), persistency of protein yield (PPY) and persistency of milk energy yield (PEY) was performed in a granddaughter design in the German Holstein dairy cattle population. The analysis included 16 paternal half-sib families with a total of 872 bulls. The analysis was carried out for the first lactation and for the first three lactations combined using univariate weighted multimarker regression. Controlling the false discovery rate across traits and data sets at a level of 0.15 and treating the four persistency traits as different traits revealed 27 significant QTL. A total of 12 chromosomes showed significant QTL effects on a chromosomewise basis. The DGAT1 effect was highly significant for PPY and protein yield. A haplotype analysis using results of previous studies of the same design revealed a co-segregation of various persistency QTL and QTL affecting health traits like dystocia and stillbirth and functional traits like non-return rate 90 and somatic cell score.
(6-June-2006)
 

Wolfová, M., Přibyl, J., Wolf, J., Zahrádková, R. 2006. "Effect of subsidy regimes on economic values of functional traits in beef cattle breeding". Journal of Animal Breeding and Genetics, 123 (2): 97-104.

KEYWORDS: Economic values, functional traits, beef cattle.

SUMMARY: The impact of five monetary subsidy regimes on economic values of traits in a cow–calf pasture production system with surplus calves fed for slaughter was investigated. The following regimes were analysed: (1) maximum prices for slaughter animals actually received in the Czech Republic during 2004, with no subsidies of any kind; (2) prices as in (1), with subsidies awarded per hectare of permanent grassland and per calf born; (3) prices as in (1), with subsidies awarded per hectare of agricultural land, per hectare of pasture and meadow, per beef cow in a forage system and per livestock unit; (4) prices as in (1), with subsidies awarded per hectare of agricultural land; (5) no subsidies, but prices received for slaughter animals that covered production costs and resulted in 1% profitability. The modeled farm showed negative profit under real price conditions with no subsidies (regime 1), which led to an underestimation of economic values for functional traits. The same results were obtained in regimes in which subsidies did not depend on the number of animals (3) or on meat production from the enterprise (4). Economic values of production traits (growth and carcass traits) did not vary among subsidy regimes. To determine optimum economic values for functional traits in beef cattle, By using the method applied in subsidy regime 5, no subsidies but prices for slaughter animals that cover production cost and a small profit.
(6-June-2006)
 

Honda, T., Fujii, T., Nomura, T., Mukai, F. 2006. "Evaluation of genetic diversity in Japanese Brown cattle population by pedigree analysis". Journal of Animal Breeding and Genetics, 123 (3): 172-179.

KEYWORDS: genetic diversity, Japanese Brown cattle, pedigree analysis

SUMMARY: The Japanese Brown is the second most common domestic beef breed in Japan. However, nowadays this breed is facing reduction in numbers because of pressure from a profitable domestic breed. This breed is uniformly characterized by its brown coat colour, but is comprised of two isolated sub-breeds, Kumamoto and Kouchi, each possessing a different gene pool. Pedigree analyses were carried out for the two sub-breeds using the pedigree records of animals born from 1970 to 2000. The effective population size has been found to be consistently reducing during the last three decades in both sub-breeds. The current effective sizes were estimated to be 25.5 and 6.0 for the Kumamoto and Kouchi sub-breeds, respectively. The estimate of the effective number of founders (Nef) in the Kumamoto sub-breed decreased from 152.1 to 74.4; that of non-founders (Nenf), from 41.7 to 5.3; and that of founder genome equivalents (Nge), from 32.7 to 4.9. The corresponding changes in the Kouchi sub-breed were from 108.2 to 79.4, 16.2 to 4.1, and 14.1 to 3.9. Increasing differences between the two genetic diversity indices in the sub-breeds indicate that the greater part of the reduction of genetic diversity can be attributed to genetic drift that accumulated in the non-founder generations. A comparison with published estimates for several cattle breeds suggests the extremely limited genetic diversity of Japanese Brown. In addition to the avoidance of further reduction of genetic diversity, it will be important to counteract the process of breed decline by establishing a production system to efficiently utilize the unique characteristics of this breed and by developing links between the breed and products with market value.
(6-June-2006)
 

Ferraz, A. L. J., Bortolossi, J. C., Curi, R. A., Ferro, M. I. T., Ferro, J. A, Furlan, L. R. 2006. "Identification and characterization of polymorphisms within the 5' flanking region, first exon and part of first intron of bovine GH gene". Journal of Animal Breeding and Genetics, 123 (3): 208-212.

KEYWORDS: polymorphisms, bovine GH gene, exon, intron

SUMMARY: The aim of the present study was to identify and characterize polymorphisms within the 5' flanking region, first exon and part of first intron of the bovine growth hormone gene among different beef cattle breeds: Nelore (n = 25), Simmental (n = 39), Simbrasil (n = 24), Simmental × Nelore (n = 30), Canchim × Nelore (n = 30) and Angus × Nelore (n = 30). Two DNA fragments (GH1, 464 bp and GH2, 453 bp) were amplified by polymerase chain reaction and then used for polymorphism identification by SSCP. Within the GH1 fragment, five polymorphisms were identified, corresponding to three different alleles: GH1.1, GH1.2 and GH1.3 (GenBank: AY662648, AY662649 and AY662650, respectively). These allele sequences were aligned and compared with bovine GH gene nucleotide sequence (GenBank: M57764 and AF118837), resulting in the identification of five insertion/deletions (INDELs) and five single nucleotide polymorphisms (SNPs). In the GH2 fragment two alleles were identified, GH2.1 and GH2.2 (GenBank: AY662651 and AY662652, respectively). The allele sequences were compared with GenBank sequences (M57764, AF007750 and AH009106) and three INDELs and four SNPs were identified. In conclusion, Six new polymorphisms of the bovine GH gene (one INDEL and five SNPs) were identified, which can be used as molecular markers in genetic studies
(6-June-2006)
 

Williams, C. B., Bennett, G. L., Jenkins, T. G., Cundiff, L. V., Ferrell, C. L. 2006. "Using simulation models to predict feed intake: Phenotypic and genetic relationships between observed and predicted values in cattle". Journal Animal Science, 84:1310-1316

KEYWORDS: cattle, feed intake, mathematical model, nutrient requirement

SUMMARY: The objectives of this study were to evaluate the accuracy of the Decision Evaluator for the Cattle Industry (DECI) and the Cornell Value Discovery System (CVDS) in predicting individual DMI and to assess the feasibility of using predicted DMI data in genetic evaluations of cattle. Observed individual animal data on the average daily DMI (OFI), ADG, and carcass measurements were obtained from postweaning records of 504 steers from 52 sires (502 with complete data). The experimental data and daily temperature and wind speed data were used as inputs to predict average daily feed DMI (kg) required (feed required; FR) for maintenance, cold stress, and ADG; maintenance and cold stress; ADG; maintenance and ADG; and maintenance alone, with CVDS (CFRmcg, CFRmc, CFRg, CFRmg, and CFRm, respectively) and DECI (DFRmcg, DFRmc, DFRg, DFRmg, and DFRm, respectively). Genetic parameters were estimated by REML using an animal model with age on test as a covariate and with genotype, age of dam, and year as fixed effects. Regression equations for observed on predicted DMI were OFI = 1.27 (SE = 0.27) + 0.83 (SE = 0.04) x CFRmcg [R2 = 0.44, residual SD (sy.x) = 0.669 kg/d] and OFI = 1.32 (SE = 0.22) + 0.8 (SE = 0.03) x DFRmcg (R2 = 0.53, sy.x = 0.612 kg/d). Heritability of OFI was 0.27 ± 0.12, and heritabilities ranged from 0.33 ± 0.12 to 0.41 ± 0.13 for predicted measures of DMI. Phenotypic and genetic correlations between OFI and CFRmcg, CFRmc, CFRg, CFRmg, CFRm, DFRmcg, DFRmc, DFRg, DFRmg, and DFRm were 0.67, 0.73, 0.41, 0.63, 0.78, 0.73, 0.82, 0.45, 0.77, and 0.86 (P < 0.001 for all phenotypic correlations); and 0.95 ± 0.07, 0.82 ± 0.13, 0.89 ± 0.09, 0.95 ± 0.07, 0.91 ± 0.09, 0.96 ± 0.07, 0.89 ± 0.09, 0.88 ± 0.09, 0.96 ± 0.06, and 0.96 ± 0.07, respectively. Phenotypic and genetic correlations between CFRmcg and DFRmcg, CFRmc and DFRmc, CFRg and DFRg, CFRmg and DFRmg, and CFRm and DFRm were 0.98, 0.94, 0.99, 0.98, and 0.95 (P < 0.001 for all phenotypic correlations), and 0.99 ± 0.004, 0.98 ± 0.017, 0.99 ± 0.004, 0.99 ± 0.005, and 0.97 ± 0.021, respectively. The strong genetic relationships between OFI and CFRmcg, CFRmg, DFRmcg, and DFRmg indicate that these predicted measures of DMI may be used in genetic evaluations and that DM requirements for cold stress may not be needed, thus reducing model complexity. However, high genetic correlations for final weight with OFI, CFRmcg, and DFRmcg suggest that the technology needs to be further evaluated in populations with genetic variance in feed efficiency.
(6-June-2006)
 

Bergen, R., Miller, S. P., Wilton, J. W., Mandell, I. B. 2006. "Genetic correlations between live yearling bull and steer carcass traits adjusted to different slaughter end points. 2. Carcass fat partitioning". Journal Animal Science, 84:558-566

KEYWORDS: cattle, fat partitioning, genetic parameters, selection, ultrasound

SUMMARY: Partial carcass dissection data from 1,031 finished crossbred beef steers were used to calculate heritabilities and genetic correlations among subcutaneous, intermuscular, and body cavity fat percentage and marbling score adjusted to slaughter age-, HCW-, fat depth-, and marbling score-constant endpoints. Genetic correlations were also calculated among these fat partitions with live growth and ultrasound traits evaluated in yearling beef bulls (n = 2,172) and steer carcass measurements. Heritabilities of the different fat partitions ranged from 0.22 (marbling score-constant body cavity fat) to 0.46 (HCW-constant marbling score). Genetic correlations between subcutaneous fat and intermuscular fat (rg = 0.16 to 0.32) and between intermuscular fat and body cavity fat (rg = 0.38 to 0.50) were more highly associated than subcutaneous fat and body cavity fat (rg = –0.08 to 0.05), indicating that fat depots are not under identical genetic control. Adjusting fat depots to different end points affected the magnitude but usually not the sign of the genetic correlations. Bull postweaning gain was associated with intermuscular (–0.24 to –0.35), body cavity (–0.24 to –0.29), and marbling fat (–0.24 to –0.39) in steers. Bull hip height was associated with body cavity (–0.20 to –0.29) and marbling fat (–0.20 to –0.47) in steers. Bull ultrasound fat depth was associated with subcutaneous (0.11 to 0.29), intermuscular (0.05 to 0.36), body cavity (0.27 to 0.49), and marbling fat (0.27 to 0.73) in steers. Bull ultrasound intramuscular fat percentage was associated with subcutaneous (–0.22 to –0.44) and intermuscular fat (–0.06 to 0.31) in steers. Bull ultrasound LM area was associated with body cavity (–0.25 to –0.31) and marbling fat (–0.25 to –0.30) in steers. Ultrasound LM width measurements were negatively correlated with subcutaneous fat (rg = –0.09 to –0.18), intermuscular fat (rg = –0.53 to –0.61), body cavity fat (rg = –0.63 to –0.69), and marbling score (rg = –0.75 to –0.87) at slaughter age-, HCW-, and fat depth-constant endpoints; correlations were generally lower at a marbling score-constant end point (rg = 0.07 to –0.49). Ultrasound indicator traits measured in seedstock may be useful in altering fat partitioning in commercial beef carcasses.
(6-June-2006)
 

Bergen, R., Miller, S. P., Wilton, J. W., Crews, D. H. Jr., Mandell, I. B. 2006. "Genetic correlations between live yearling bull and steer carcass traits adjusted to different slaughter end points. 1. Carcass lean percentage". Journal Animal Science, 84:546-557

KEYWORDS: cattle, end point, genetic parameter, selection, ultrasound

SUMMARY: Genetic relationships between age-constant live yearling beef bull growth and ultrasound traits and steer carcass traits with dissected steer carcass lean percentage adjusted to slaughter age-, HCW-, fat depth-, and marbling score-constant end points were studied. Three measures of steer carcass lean percentage were used. Blue Tag lean percentage (BTLean) was predicted from HCW, fat depth, and LM area measurements. Ruler lean percentage (RulerLean) was predicted from carcass fat depth and LM depth and width measurements. Dissected lean percentage (DissLean) was based on dissection of the 10–11–12th rib section. Both BTLean (h2 = 0.30 to 0.44) and DissLean (h2 = 0.34 to 0.39) were more heritable than RulerLean (h2 = 0.05 to 0.14) at all end points. Genetic correlations among DissLean and RulerLean (rg = 0.61 to 0.70), DissLean and BTLean (rg = 0.56 to 0.72), and BTLean and RulerLean (rg = 0.59 to 0.90) indicated that these traits were not genetically identical. Adjusting Diss-Lean to different end points changed the magnitude, but generally not the direction, of genetic correlations with indicator traits. Ultrasound scan-age-constant live yearling bull lean percentage estimates were heritable (h2 = 0.26 to 0.42) and genetically correlated with each other (rg = 0.68 to 0.99) but had greater correlations with DissLean at slaughter age (rg = 0.24 to 0.48) and HCW (rg = 0.16 to 0.40) end points than at fat depth (rg = –0.08 to 0.13) and marbling score (rg = 0.02 to 0.11) end points. Scan-age-constant yearling bull ultrasound fat depth also had stronger correlations with DissLean at slaughter age (rg = –0.34) and HCW (rg = –0.25) than at fat depth (rg = –0.02) and marbling score (rg = –0.03) end points. Yearling bull scan-age-constant ultrasound LM area was positively correlated with DissLean at all endpoints (rg = 0.11 to 0.23). Genetic correlations between yearling bull LM method 1 width (rg = 0.38 to 0.56) and method 2 depth (rg = –0.17 to –0.38) measurements with DissLean suggested that LM shape may be a valuable addition to genetic improvement programs for carcass lean percentage at slaughter age, HCW, and fat depth constant end points. At all end points, steer carcass fat depth (rg = –0.60 to –0.64) and LM area (rg = 0.48 to 0.59) had stronger associations with DissLean than did corresponding live yearling bull measurements. Improved methods that combine live ultrasound and carcass traits would be beneficial for evaluating carcass lean percentage at fat depth or marbling score end points.
(6-June-2006)
 

Casas, E., White, S. N., Wheeler, T. L., Shackelford, S. D., Koohmaraie, M., Riley, D. G., Chase, C. C. Jr., Johnson, D. D., Smith, T. P. L. 2006. "Effects of calpastatin and µ-calpain markers in beef cattle on tenderness traits". Journal Animal Science, 84:520-525

KEYWORDS: µ-calpain, calpastatin, cattle, genetic marker, meat tenderness, shear force

SUMMARY: The objective of this study was to assess the association of single nucleotide polymorphisms (SNP) developed at the calpastatin (CAST) and µ-calpain (CAPN1) genes with meat tenderness and palatability traits in populations with diverse genetic backgrounds. Three populations were used in the study. One population consisted of Bos taurus that included crossbred animals derived from Hereford, Angus, Red Angus, Limousin, Charolais, Gelbvieh, and Simmental (GPE7; n = 539). Another population consisted of Bos taurus with Bos indicus influence, including crossbred animals from Hereford, Angus, Brangus, Beefmaster, Bonsmara, and Romosinuano (GPE8; n = 580). The third population was Bos indicus and consisted of purebred Brahman (STARS; n = 444). Traits evaluated were meat tenderness measured as Warner-Bratzler shear force (WBSF; kg) at 14 d postmortem, and traits evaluated by trained sensory panels that included tenderness score, juiciness, and flavor intensity. A SNP at the CAST gene had a significant (P < 0.003) effect on WBSF and tenderness score in the GPE7 and GPE8 populations. Animals inheriting the TT genotype at CAST had meat that was more tender than those inheriting the CC genotype. The marker at the CAPN1 gene was significant (P < 0.03) for tenderness score in GPE7 and GPE8. Animals inheriting the CC genotype at CAPN1 had meat that was more tender than those inheriting the TT genotype. Markers at the CAST and CAPN1 genes were associated with flavor intensity in the GPE8 population. Animals inheriting the CC genotype at CAST and the TT genotype at CAPN1 produced steaks with an intense flavor when compared with the other genotypes. An interaction between CAST and CAPN1 was detected (P < 0.05) for WBSF on GPE8. The statistical significance of the interaction is questionable because of the limited number of observations in some cells. Markers developed at the CAST and CAPN1 genes are suitable for use in identifying animals with the genetic potential to produce meat that is more tender.
(6-June-2006)
 

Powell R. L., Norman H. D. 2006. "Major Advances in Genetic Evaluation Techniques". Journal of Dairy Science, 89:1337-1348

KEYWORDS: genetic evaluation, Interbull, evaluation accuracy, somatic cell score

SUMMARY: The past quarter-century in genetic evaluation of dairy cattle has been marked by evolution in methodology and computer capacity, expansion in the array of evaluated traits, and globalization. Animal models replaced sire and sire-maternal grandsire models and, more recently, application of Bayesian theory has become standard. Individual test-day observations have been used more effectively in estimation of lactation yield or directly as input to evaluation models. Computer speed and storage are less limiting in choosing procedures. The increased capabilities have supported evaluation of additional traits that affect the net profitability of dairy cows. The importance of traits other than yield has increased, in a few cases due to an antagonistic relationship with yield. National evaluations combined internationally provide evaluations for bulls from all participating countries on each of the national scales, facilitating choices from among many more bulls. Selection within countries has increased inbreeding and the use of similar genetics across countries reduces the previously available outcross population. Concern about inbreeding has prompted changes in evaluation methodology and mating practices, and has promoted interest in crossbreeding. In just the past decade, distribution of genetic evaluations has gone from mailed paper or computer tapes for a limited audience to publicly accessible, request-driven distribution via the Internet. Among the distributed information is a choice of economic indices that combine an increasing array of traits into numbers reflecting breeding goals under different milk-pricing conditions. Considerable progress in genomics and the mapping of the bovine genome have identified markers for some deleterious recessive genes, but broader benefits of marker-assisted selection are still in the future. A possible exception is the proprietary use of DNA testing by semen producers to select among potential progeny test bulls. The collection and analysis of industry-wide data to evaluate genetic merit will continue to be the most important tool for genetic progress into the foreseeable future.
(6-June-2006)
 

Shook, G. E. 2006. "Major Advances in Determining Appropriate Selection Goals". Journal of Dairy Science, 89:1349-1361

KEYWORDS: selection index, total economic merit

SUMMARY: Substantial increases of 3,500 kg of milk, 130 kg of fat, and 100 kg of protein per cow per lactation have resulted from improvements in genetics, nutrition, and management during the past 20 yr. At the same time, the interval from calving to conception increased (unfavorable) by 24 d. Genetics has accounted for about 55% of gains in the yield traits and about one-third of the change in interval to conception. Genetic gains in the yield traits and productive life have accumulated to around 1.7 and 1.2 genetic standard deviations since 1980. Unfavorable genetic changes in conception interval since 1980 and somatic cell score since 1990 have accumulated to 1.0 and 0.12 genetic standard deviations. The most important advance in selection indexes has been the introduction of nonyield traits. Advances in selection indexes have gone hand in hand with advances in data collection and genetic evaluation. As new traits were recorded in dairy management databases and as genetic evaluations were developed for these traits, they were incorporated into selection indexes. Until 1994, when somatic cell score and productive life were introduced, selection indexes provided by USDA included only yield traits. In 2000, composite type indexes for udder, feet and legs, and body size were added. Daughter pregnancy rate and service sire- and daughter-calving ease were included in 2003. The lifetime merit indexes introduced in 2003 have, for the first time, resulted in theoretical selection responses in the desired direction for all traits. During this time, the percentage relative economic weights in selection indexes increased from 0 to 45% for the nonyield traits. Selection emphasis on nonyield traits should continue to increase as additional traits (e.g., calf survival, metabolic disease, and male fertility) are introduced in the future. Wide variation exists among countries in traits included in selection indexes and in relative economic weights. Molecular genetic studies have identified many chromosome regions with potentially important major genes for economic traits. Use of DNA markers for genetic improvement is currently limited by lack of precision in marker location. Discovery of major genes will be accelerated by the availability of the bovine genome sequence, comparative genome maps and genome sequences across species, and increased use of breed crosses in molecular studies. As major genes are identified, their effects will be incorporated into genetic evaluations and selection indexes.
(6-June-2006)
 

Funk, D. A. 2006. "Major Advances in Globalization and Consolidation of the Artificial Insemination Industry". Journal of Dairy Science, 89:1362-1368

KEYWORDS: progeny test, genetic marker, Interbull, inbreeding

SUMMARY: The artificial insemination (AI) industry in the United States has gone through many consolidations, mergers, and acquisitions over the past 25 yr. There are 5 major AI companies in the United States today: 3 large cooperatives, 1 private company, and 1 public company. The latter 2 have majority ownership outside of the United States. The AI industry in the United States progeny-tests more than 1,000 Holstein young sires per year. Because healthy, mature dairy bulls are capable of producing well over 100,000 straws of frozen semen per year, only a relatively small number of bulls are needed to breed the world’s population of dairy cows. Most AI companies in the United States do not own many, if any, females and tend to utilize the same maternal families in their breeding programs. Little differences exist among the selection programs of the AI companies in the United States. The similarity of breeding programs and the extreme semen-production capabilities of bulls have contributed to difficulties the AI companies have had in developing genetically different product lines. Exports of North American Holstein genetics increased steadily from the 1970s into the 1990s because of the perceived superiority of North American Holsteins for dairy traits compared with European strains, especially for production. The breeding industry moved towards international genetic evaluations of bulls in the 1990s, with the International Bull Evaluation Service (Interbull) in Sweden coordinating the evaluations. The extensive exchange of elite genetics has led to a global dairy genetics industry with bulls that are closely related, and the average inbreeding level for the major dairy breeds continues to increase. Genetic markers have been used extensively and successfully by the industry for qualitative traits, especially for recessive genetic disorders, but markers have had limited impact for quantitative traits. Selection emphasis continues to migrate away from production traits and towards nonproduction traits, especially towards health and fitness traits. Specifically, fertility has arguably become the major breeding and management issue facing dairy farmers today. Some producers have implemented crossbreeding programs in an effort to capitalize on heterosis, and crossbreeding will almost certainly need to be a bigger part of the AI companies business in the years ahead.
(6-June-2006)
 

Kuhn, M.T., Hutchison, J.L. Norman, H.D. 2006. "Dry Period Length to Maximize Production Across Adjacent Lactations and Lifetime Production". Journal of Dairy Science, 89:1713-1722

KEYWORDS: days dry, lifetime production

SUMMARY: The primary objectives of this research were to determine the dry period lengths that maximize production across adjacent lactations and also dry period length that maximizes lifetime yield. Effect of days dry (DD) after lactations 1 through 3 were determined separately for both adjacent lactation sums and lifetime yield. Field data, collected through the Dairy Herd Improvement Association, on US Holstein cows first calving between January 1997 and January 2004 were utilized. Lifetime records were restricted to cows first calving no later than December 1999. Actual lactation yields, in contrast to standardized records, were used to calculate lactation sums and lifetime records. Herds were required to be on test for the entire period to avoid partial records. Another important edit was that actual calving dates had to agree with expected calving dates, based on reported days open, within 10 d. This edit ensured that the producer knew, at least at one point in time, when the cow was going to calve. Cow effects were corrected for in both the adjacent lactation and lifetime analyses. The minimum DD to maximize production across adjacent lactations depended on parity. For yield across first and second lactations, there was little loss in production with a minimum of 40 to 45 DD. Longer dry periods (55 to 65 DD) were required after second and third lactations however, presumably due to the lower persistency of second and later lactation cows. Lifetime production was maximized by 40 to 50 DD after first lactation and 30 to 40 DD after second and later lactations. Fewer DD were required to maximize lifetime yield than adjacent lactation yield because cows with fewer DD also had more lifetime days in milk. Although dry periods of 30 to 40 d can be used after second and later lactations without cost in lifetime yield, their benefit to lifetime production is minimal. Dry periods shorter than 30 d or longer than 70 d are costly to lifetime yield and should be avoided. Dry periods longer than 80 d are even more costly than dry periods less than 30 d.
(6-June-2006)
 

Hand, K.J., Lazenby, D., Miglior, F. Kelton, D.F. 2006. "Short Communication: Comparison of Protocols to Estimate Twenty-Four-Hour Fat and Protein Percentages for Herds with a Robotic Milking System". Journal of Dairy Science, 89:1723-1726

KEYWORDS: milk recording, sampling protocol, automatic milking system

SUMMARY: Currently, different protocols are used in various countries to estimate the 24-h fat and protein percentages for dairy cows that are milked with an automatic milking system. These protocols include estimating 24-h fat and protein percentages from 1) single samples from all animals in the herd; 2) single samples of fat adjusted for covariates and single samples of protein unadjusted for covariates; or 3) all samples (adjusted and unadjusted) collected on test days where test days vary in length from 10 to 18 h. The accuracy of estimated component percentages in predicting observed percentages was determined via agreement analysis for four protocols. Analysis of the data suggests collecting all samples (unadjusted for covariates) during a sampling period of at least 16 h on test day to be the most accurate protocol when estimating 24-h fat and protein percentages in herds with automatic milking systems.
(6-June-2006)
 

Mulder, H.A., Bijma, P. 2006. "Benefits of Cooperation Between Breeding Programs in the Presence of Genotype by Environment Interaction". Journal of Dairy Science, 89:1727-1739

KEYWORDS: genotype x environment interaction, breeding program, dairy cattle, genetic gain

SUMMARY: Dairy cattle breeding programs and dairy farmers are selecting sires and dams across environments. Genotype x environment interaction (G x E) limits the possibilities for cooperation between breeding programs operating in different environments. The objectives of this study were 2-fold: 1) to investigate the effects of heritability, selection intensity, number of progeny per bull, and size of breeding programs on possibilities for cooperation between dairy cattle breeding programs in the short and long term in the presence of G x E, and 2) to quantify the effect of such cooperation on genetic gain. A dairy cattle situation with 2 breeding programs operating in 2 environments was simulated using a deterministic pseudo-BLUP selection index model. Long-term cooperation between the 2 breeding programs was possible in the presence of G x E, when the genetic correlation was higher than 0.80 to 0.90, resulting in up to 15% extra genetic gain. In addition, in the initial generations of selection, the breeding programs could benefit from mutually selecting sires and dams from each other when the genetic correlation was as low as 0.40 to 0.60. With more intense selection, breeding programs were less likely to benefit from cooperation with breeding programs in other environments. Heritability and number of progeny per bull had little effect on possibilities for cooperation, unless the heritabilities and the number of progeny per bull were extremely different in the 2 environments. Small breeding programs benefited more from cooperation than did large breeding programs, and benefits were possible even at lower values (i.e., <0.80) of the genetic correlation. Possibilities for cooperation across environments would affect the optimal design of dairy cattle breeding programs considering genetic gain, inbreeding, and costs.
(6-June-2006)
 

Mulder, H.A., Veerkamp, R.F., Ducro, B.J., van Arendonk, J. A. M. Bijma, P. 2006. "Optimization of Dairy Cattle Breeding Programs for Different Environments with Genotype by Environment Interaction". Journal of Dairy Science, 89:1740-1752

KEYWORDS: genetic gain, dairy cattle, breeding program, genotype x environment interaction

SUMMARY: Dairy cattle breeding organizations tend to sell semen to breeders operating in different environments and genotype x environment interaction may play a role. The objective of this study was to investigate optimization of dairy cattle breeding programs for 2 environments with genotype x environment interaction. Breeding strategies differed in 1) including 1 or 2 environments in the breeding goal, 2) running either 1 or 2 breeding programs, and 3) progeny testing bulls in 1 or 2 environments. Breeding strategies were evaluated on average genetic gain of both environments, which was predicted by using a pseudo-BLUP selection index model. When both environments were equally important and the genetic correlation was higher than 0.61, the highest average genetic gain was achieved with a single breeding program with progeny-testing all bulls in both environments. When the genetic correlation was lower than 0.61, it was optimal to have 2 environment-specific breeding programs progeny-testing an equal number of bulls in their own environment only. Breeding strategies differed by 2 to 12% in average genetic gain, when the genetic correlation ranged between 0.50 and 1.00. Ranking of breeding strategies, based on the highest average genetic gain, was relatively insensitive to heritability, number of progeny per bull, and the relative importance of both environments, but was very sensitive to selection intensity. With more intense selection, running 2 environment-specific breeding programs was optimal for genetic correlations up to 0.70–0.80, but this strategy was less appropriate for situations where 1 of the 2 environments had a relative importance less than 10 to 20%. Results of this study can be used as guidelines to optimize breeding programs when breeding dairy cattle for different parts of the world.
(6-June-2006)
 

Khatib, H., Leonard, S.D., Schutzkus, V., Luo W., Chang Y.M. 2006. "Association of the OLR1 Gene with Milk Composition in Holstein Dairy Cattle". Journal of Dairy Science, 89:1753-1760

KEYWORDS: candidate gene, milk composition, oxidized low-density lipoprotein receptor

SUMMARY: Oxidized low-density lipoprotein receptor (OLR1) is the major protein that binds, internalizes, and degrades oxidized low-density lipoprotein. The role of OLR1 in lipid metabolism and the results of previous whole-genome scan studies prompted the investigation of OLR1 as a candidate gene affecting milk composition traits. Direct cDNA and genomic sequencing of OLR1 revealed 2 single nucleotide polymorphisms (SNP) in exon 4, 5 SNP in intron 4, and 1 in the 3' untranslated region (UTR). Four intragenic haplotypes comprising SNP positions 7,160, 7,161, 7,278, 7,381, 7,409, 7,438, 7,512, and 8,232 were inferred. Haplotype analysis showed that one of the haplotypes was associated with a significant increase in fat yield and fat percentage. Single SNP analysis showed that allele C of SNP 8,232 (in the 3'-UTR) had significant effects on fat yield and fat percentage, whereas SNP 7,160 and 7,161 (in exon 4) had no significant effects. Both single SNP and haplotype analyses indicate that SNP 8,232 in the 3'-UTR is associated with milk fat yield and percentage and it may be in linkage disequilibrium with the functional polymorphism. To provide support for the hypothesis that SNP 8,232 is responsible for OLR1 expression, OLR1 expression levels in individuals bearing different genotypes were assessed. It was found that OLR1 expression was reduced in genotype AA individuals compared with CC and AC individuals, suggesting that A at position 8,232 may be the nucleotide causing decreased OLR1 expression. The 3'-UTR polymorphism found in this study might control translation or stability of OLR1 mRNA.
(6-June-2006)
 

Zhou, Y., Jiang, H. 2006. "Short Communication: A Milk Trait-Associated Polymorphism in the Bovine Growth Hormone Receptor Gene Does Not Affect Receptor Signaling". Journal of Dairy Science, 89:1761-1764

KEYWORDS: single nucleotide polymorphism, growth hormone receptor, milk production

SUMMARY: Growth hormone (GH), also known as somatotropin, stimulates milk production in cows. At the tissue level, the action of GH is mediated by the GH receptor (GHR) and the receptor-activated intracellular signaling pathway involving Janus kinase 2 (JAK2) and signal transducer and activator of transcription 5 (STAT5). A T/A nucleotide variation in exon 8 of the bovine GHR gene, resulting in a phenylalanine to tyrosine change in the transmembrane domain of the GHR protein, has been reported to be associated with a major effect on milk yield in cows. The objective of this study was to determine whether the 2 versions of GHR differ in mediating GH-induced STAT5 activation of gene expression. cDNA expression plasmids were created for the 2 versions of GHR and cotransfected each of them with a STAT5 expression plasmid and a luciferase reporter gene construct containing STAT5 binding sites into 2 different cell lines. Treatment of the transfected cells with various concentrations of GH triggered a dose-dependent increase in luciferase activity. However, the GH-induced luciferase activity was not different between the 2 GHR expression plasmids, indicating that the 2 GHR forms did not differ in mediating GH-induced STAT5 activation of gene expression. Thus, if the T/A polymorphism in exon 8 of the GHR gene has a causative effect on milk production, this effect is unlikely to be mediated by the JAK2-STAT5 pathway, the currently known major signaling pathway from the growth hormone receptor.
(6-June-2006)
 

Sewalem, A. Kistemaker, G.J., Miglior, F., Van Doormaal, B.J. 2006. "Analysis of Inbreeding and Its Relationship with Functional Longevity in Canadian Dairy Cattle". Journal of Dairy Science, 89:2210-2216

KEYWORDS: functional longevity, inbreeding level, inbreeding depression

SUMMARY: The aim of this study was to assess the level of inbreeding and its relationship to the functional survival of Canadian dairy breeds by using a Weibull proportional hazard model. Data consisted of records from 72,385 cows in 1,505 herds from 2,499 sires for Jerseys, 112,723 cows in 1,482 herds from 2,926 sires for Ayrshires, and 1,977,311 cows in 17,182 herds from 8,261 sires for Holsteins. Longevity was defined as the number of days from first calving to culling, death, or censoring. Inbreeding coefficients (F) were grouped into 7 classes (F = 0, 0 < F < 3.125, 3.125 F < 6.25, 6.25 F <12.5, 12.5 F < 18.25, 18.25 F < 25.0, and F 25.0%). The statistical model included the effects of stage of lactation, season of production, the annual change in herd size, type of milk recording supervision, age at first calving, effects of milk, fat, and protein yields calculated as within herd-year-parity deviations, herd-year-season of calving, inbreeding, and sire. The relative culling rate was calculated for animals in each class after accounting for the above-mentioned effects. A trend toward increased risk of culling among more inbred animals was observed for all breeds. Little difference in survival was observed for cows with 0 < F <12.5%. The relative risk ratios (relative to F = 0) for cows with inbreeding coefficients up to 12.5% were 1.19, 1.16, and 1.14 for Jersey, Ayrshire, and Holstein cows, respectively. Greater effects of inbreeding were seen, however, when F increased beyond 12.5%.
(6-June-2006)
 

Hawken, R.J., Cavanagh, J.A.L., Meadows, J.R.S., Khatkar, M.S., Husaini, Y., Zenger, K.R., McClintock, S., McClintock, A.E., Raadsma, H.W. 2006. "Technical Note: Whole-Genome Amplification of DNA Extracted from Cattle Semen Samples". Journal of Dairy Science, 89:2217-2221

KEYWORDS: whole-genome amplification, GenomiPhi, REPLI-g, DNA extraction

SUMMARY: The bovine genome sequence project and the discovery of many thousands of bovine single nucleotide polymorphisms has opened the door for large-scale genotyping studies to identify genes that contribute to economically important traits with relevance to the beef and dairy industries. Large amounts of DNA will be required for these research projects. This study reports the use of the whole-genome amplification (WGA) method to create an unlimited supply of DNA for use in genotyping studies and long-term storage for future gene discovery projects. Two commercial WGA kits (GenomiPhi, Amersham Biosciences, Sydney, Australia, and REPLI-g, Qiagen, Doncaster, Australia) were used to amplify DNA from straws of bull semen, resulting in an average of 7.2 and 67 µg of DNA per reaction, respectively. The comparison of 3.5 kb of sequences from the amplified and unamplified DNA indicated no detectable DNA differences. Similarly, gene marker analysis conducted on genomic DNA and DNA after WGA indicated no difference in marker amplification or clarity and accuracy of scoring for approximately 10,000 single nucleotide polymorphism markers when compared with WGA samples genotyped in duplicate. These results illustrate that WGA is a suitable method for the amplification and recovery of DNA from bull semen samples for routine genomic investigations.
(6-June-2006)
 

Banos, G., Coffey, M.P., Wall, E., Brotherstone, S. 2006. "Genetic Relationship Between First-Lactation Body Energy and Later-Life Udder Health in Dairy Cattle". Journal of Dairy Science, 89:2222-2232

KEYWORDS: energy trait, udder health, dairy cattle

SUMMARY: Weekly body condition score (BCS) and live weight records were used to calculate energy content (EC) and cumulative effective energy balance (CEEB) for 508 Holstein-Friesian cows in their first lactation. Cows were raised on an experimental farm and had calved between 1991 and 2000. Energy content was an estimate of the actual energy level of a cow at any given stage of lactation, whereas CEEB was associated with the total body energy content as defined by accumulated weekly energy balance changes since the onset of lactation. Genetic evaluations were computed for the 3 body energy traits (BCS, EC, and CEEB) for each week of first lactation. Random regression models were used to assess the association between first-lactation weekly genetic evaluations for body energy and monthly test-day log-transformed SCC, clinical mastitis, and other udder problems in the first 3 lactations. There was a significant effect of at least one body energy trait at any stage of first lactation past wk 3 on SCC in the first 3 lactations. Maximum genetic correlation estimates were –0.18 (±0.04) between wk-16 BCS and SCC in the first 2 lactations, –0.18 (±0.04) between wk-11 EC and SCC in the first 2 lactations, and –0.17 (±0.07) between wk-6 CEEB and SCC in the first 2 lactations. The effect of body energy traits on clinical mastitis was, in general, nonsignificant; nevertheless, moderate genetic correlations were estimated, ranging from –0.05 (±0.07) to –0.25 (±0.15). The effect of body energy traits on udder problems other than mastitis was negligible in all cases. Results suggest that, amongst the traits studied here, BCS, EC, and CEEB in the first 3 to 4 mo of lactation 1 had the greatest genetic association with SCC and mastitis in first, second, and, to a lesser extent, third lactations.
(6-June-2006)
 

Liu, Y.X., Zhang, J., Schaeffer, L.R., Yang, R.Q., Zhang W.L. 2006. "Short Communication: Optimal Random Regression Models for Milk Production in Dairy Cattle". Journal of Dairy Science, 89:2233-2235

KEYWORDS: random regression model, optimization, statistical criteria

SUMMARY: Legendre polynomials of orders 3 to 8 in random regression models (RRM) for first-lactation milk production in Canadian Holsteins were compared statistically to determine the best model. Twenty-six RRM were compared using LP of order 5 for the phenotypic age-season groupings. Variance components of RRM were estimated using Bayesian estimation via Gibbs sampling. Several statistical criteria for model comparison were used including the total residual variance, the log likelihood function, Akaike’s information criterion, the Bayesian information criterion, Bayes factors, an information-theoretic measure of model complexity, and the percentage relative reduction in complexity. The residual variance always picks the model with the most parameters. The log likelihood and information-theoretic measure picked the model with order 5 for additive genetic effects and order 7 for permanent environmental effects. The currently used model in Canada (order 5 for both additive and permanent environmental effects) was not the best for any single criterion, but was optimal when considering all criteria.
(6-June-2006)
 

Heringstad, B., Gianola, D., Chang, Y.M., Ødegård, J., Klemetsdal G. 2006. "Genetic Associations Between Clinical Mastitis and Somatic Cell Score in Early First-Lactation Cows". Journal of Dairy Science, 89:2236-2244

KEYWORDS: clinical mastitis, dairy cattle, genetic correlation, somatic cell score

SUMMARY: The objectives of this study were to examine genetic associations between clinical mastitis and somatic cell score (SCS) in early first-lactation cows, to estimate genetic correlations between SCS of cows with and without clinical mastitis, and to compare genetic evaluations of sires based on SCS or clinical mastitis. Clinical mastitis records from 15 d before to 30 d after calving and first test-day SCS records (from 6 to 30 d after calving) from 499,878 first-lactation daughters of 2,043 sires were analyzed. Results from a bivariate linear sire model analysis of SCS in cows with and without clinical mastitis suggest that SCS is a heterogeneous trait. Heritability of SCS was 0.03 for mastitic cows and 0.08 for healthy cows, and the genetic correlation between the 2 traits was 0.78. The difference in rank between sire evaluations based on SCS of cows with and without clinical mastitis varied from –994 to 1,125, with mean 0. A bivariate analysis with a threshold-liability model for clinical mastitis and a linear Gaussian model for SCS indicated that heritability of liability to clinical mastitis is at least as large as that of SCS in early lactation. The mean (standard deviation) of the posterior distribution of heritability was 0.085 (0.006) for liability to clinical mastitis and 0.070 (0.003) for SCS. The posterior mean (standard deviation) of the genetic correlation between liability to clinical mastitis and SCS was 0.62 (0.03). A comparison of sire evaluations showed that genetic evaluation based on SCS was not able to identify the best sires for liability to clinical mastitis. The association between sire posterior means for liability to clinical mastitis and sire predicted transmitting ability for SCS was far from perfect.
(6-June-2006)
 

Ku erová, J., Lund, M.S., Sørensen, P., Sahana, G., Guldbrandtsen, B., Nielsen, V.H., Thomsen, B., Bendixen, C. 2006. "Multitrait Quantitative Trait Loci Mapping for Milk Production Traits in Danish Holstein Cattle". Journal of Dairy Science, 89:2245-2256

KEYWORDS: QTL mapping, pleiotropy, multitrait analysis, milk production trait

SUMMARY: The aims of this study were (1) to confirm previously identified quantitative trait loci (QTL) on bovine chromosomes 6, 11, 14, and 23 in the Danish Holstein cattle population, (2) to assess the pleiotropic nature of each QTL on milk production traits by building multitrait and multi-QTL models, and (3) to include pedigree information on nongenotyped individuals to improve the estimation of genetic parameters underlying the random QTL model. Nineteen grandsire families were analyzed by single-trait (ST) and multitrait (MT) QTL mapping methods. The variance component-based QTL mapping model was implemented via restricted maximum likelihood (REML) to estimate QTL position and parameters. Segregation of the previously identified QTL was confirmed on bovine chromosomes 6, 11, and 14, but not on 23. A highly significant (1% chromosome-wise level) QTL was found on chromosome 6, between 37 and 73 cM. This QTL had a strong effect on protein percentage (PP) and fat percentage (FP) according to ST analyses, and effects on PP, FP, milk yield (MY), fat yield (FY), and protein yield (PY) in MT analyses. A QTL affecting PP was detected on chromosome 11 (at 70 cM) using ST analysis. The MT analysis revealed a second QTL (at 67 cM) approaching significance with an effect on MY. The ST analysis identified a QTL for MY and FP on chromosome 14, between 10 and 24 cM. The extended pedigree (nongenotyped animals) was included to estimate genetic parameters underlying the random QTL model; that is, additive polygenic and QTL variances. In general, the estimates of the QTL variance components were smaller but more precise when the extended pedigree was considered in the analysis.
(6-June-2006)
 

Croquet, C., Mayeres, P., Gillon, A., Vanderick, S., Gengler, N. 2006. "Inbreeding Depression for Global and Partial Economic Indexes, Production, Type, and Functional Traits". Journal of Dairy Science, 89:2257-2267

KEYWORDS: incomplete pedigree, inbreeding, global economic index, genetic evaluation

SUMMARY: The objective of this research was to examine the effects of inbreeding in the population of Holstein cattle in the Walloon region of Belgium. The effects of inbreeding on the global economic index and its components were studied by using data from the genetic evaluations of February 2004 for production, somatic cell score (SCS), computed from somatic cell counts and type. Inbreeding coefficients for 956,516 animals were computed using a method that allows assigning an inbreeding coefficient to individuals without known parents. These coefficients were equal to the mean inbreeding coefficient of contemporary individuals with known parents. The significance of inbreeding effects on the different evaluated traits and on the different indexes were tested using a t-test comparing estimated standard errors and effects. The inbreeding effect was significantly different from zero for the vast majority of evaluated traits and for all of the indexes. Inbreeding had the greatest deleterious effects on production traits. Inbreeding decreased yield of milk, fat, and protein during a lactation by 19.68, 0.96, and 0.69 kg, respectively, per each 1% increase in inbreeding. The regression coefficient of SCS per 1% increase in inbreeding was +0.005 SCS units. The inbreeding depression was thus relatively low for SCS, but inbred animals had higher SCS than non-inbred animals, indicating that inbred animals would be slightly more sensitive to mastitis than non-inbred animals. Estimates of inbreeding effects on evaluated type traits per 1% increase were small. The most strongly affected type traits were chest width, rear leg, and overall development on a standardized scale. For several type traits, particularly traits linked to the udder, the estimates suggested a favorable effect of inbreeding. The global economic index was depressed by around 6.13 of lifetime profit per 1% increase in inbreeding for the Holstein animals in the Walloon region of Belgium.
(6-June-2006)
 

Dhara, K. C., Ray, N., Sinha, R. 2006. "Factors affecting production of F1 crossbred dairy cattle in West Bengal". Livestock Research for Rural Development,18 (#51):
http://www.cipav.org.co/lrrd/lrrd18/4/dhar18051.htm

KEYWORDS: Age of calving, half bred, lactation length, milk yield at 300 days, season of birth

SUMMARY: Season of birth had no influence on age at first, second and third calving, lactation length and 300 days' milk yield of three consecutive lactations of Jersey X Hariana, Holstein Friesian X Hariana and Brown Swiss X Hariana cattle in West Bengal except first lactation length. First lactation length of cattle calved in the monsoon was higher than those calved during summer and winter season. The influence of different genetic groups was significant in case of age at first and third calving and 300 days' milk yield of three consecutive lactations. It was found that productive efficiency was better in either B x H cross or F x H crosses.
(6-June-2006)
 

Forabosco, F., Bozzi, R., Filippini, F., Boettcher, P., Van Arendonk, J.A.M., Bijma, P. 2006. "Linear model vs. survival analysis for genetic evaluation of sires for longevity in Chianina beef cattle". Livestock Science, 101 (1-3): 191-198

KEYWORDS: Beef cattle; Chianina; Genetic parameters; Breeding values; Longevity

SUMMARY: The objective of this study was to compare sire EBVs for longevity in Chianina beef cattle estimated with linear models and survival analysis. Two datasets were created, one considered all data (SURVall), the other only uncensored records (SURVun). The linear models were used to analyze longevity measured as three correlated dichotomous (yes/no) measures of survival in the first three parities (LIN-S3) and as an overall measure of lifespan in months (LIN-LPL). Correlation between sire EBVs from the two survival analyses were 0.85. For LIN-S3 the correlations of EBVs across parities were between 0.69 to 0.93. Medium correlations (from 0.50 to 0.62) were found when only uncensored data (SURVun) were compared to the linear model (LIN-S3). Higher correlations (from 0.71 to 0.93) were found when EBV based on both censored and uncensored data (SURVall) were compared to LIN-S3. Heritability was estimated at 0.11, 0.09 and 0.08 for SURVall, SURVun and LIN-LPL, respectively; and 0.05, 0.02 and 0.02, respectively, for survival in the first three parities according to LIN-S3. Linear and non-linear models differed in many aspects; the most precise EBV were obtained when all data was used in the evaluation.
(6-June-2006)
 

Curi, R.A., Palmieri, D.A., Suguisawa, L., Ferraz, A.L.J., de Oliveira, H.N., Furlan, L.R., Silveira, A.C., Lopes, C.R. 2006. "Effects of GHR gene polymorphisms on growth and carcass traits in Zebu and crossbred beef cattle". Livestock Science, 101 (1-3): 94-100

KEYWORDS: Beef cattle; Polymorphisms; GHR; Growth; Carcass.

SUMMARY: The growth hormone receptor (GHR) is the cell surface receptor for growth hormone (GH) and is required for GH to carry out its effects on target tissues. The objectives of the present study were to estimate the allele and genotype frequencies of the GHR/Alu I gene polymorphism located in the regulatory region in beef cattle belonging to different genetic groups and to determine associations between this polymorphism and growth and carcass traits. Genotyping was performed on 384 animals, including 79 Nellore (Zebu), 30 Canchim (5/8 Charolais + 3/8 Zebu), 30 Simmental × Nellore crossbred and 245 Angus × Nellore crossbred cattle. Alleles Alu I(+), Alu I(−) and Alu I(N)–null allele–were evidenced for the GHR/Alu I polymorphism and the frequency of the Alu I(N) allele was significantly higher than the frequency of the Alu I(+) and Alu I(−) alleles in all genetic groups. Genotype Alu I(N/N) of the GHR/Alu I predominated in Nellore animals, while the Alu I(N/+) and Alu I(N/−) predominated in the other genetic groups. In the association studies, traits of interest were analyzed using the General Linear Model (GLM) procedure of the SAS program and least squares means of the genotypes were compared by the Tukey test. Significant associations (P < 0.05) were observed between the Alu I(N/N) genotype of the GHR/Alu I polymorphism and lower weight gain and body weight at slaughter, although a confounding between genotypes and genetic groups may have occurred.
(6-June-2006)
 

Hoque, M.A., Arthur, P.F., Hiramoto, K., Oikawa, T. 2006. "Genetic parameters for carcass traits of field progeny and their relationships with feed efficiency traits of their sire population for Japanese Black cattle". Livestock Science, 100 (2-3): 251-260

KEYWORDS: Genetic parameters; Beef cattle; Feed efficiency; Correlated response; Carcass traits

SUMMARY: Genetic parameters for carcass traits of 1774 field progeny (1281 steers and 493 heifers), and their genetic relationships with feed efficiency traits of their sire population (740 bulls) were estimated with REML. Feed efficiency traits included feed conversion ratio (FCR) and residual feed intake (RFI). RFI was calculated by the residual of phenotypic (RFIphe) and genetic (RFIgen) regression from the multivariate analysis of feed intake on metabolic weight and daily gain. Progeny traits were carcass weight (CWT), rib eye area (REA), rib thickness (RBT), subcutaneous fat, yield estimate (YEM), marbling score (MSR), meat quality grade, meat color, fat color, meat firmness and meat texture. The estimated heritability for CWT (0.70) was high and heritabilities for all the other traits were moderate (ranged from 0.32 to 0.47), except for meat and fat color and meat texture which were low (ranged from 0.02 to 0.25). The high genetic correlation (0.62) between YEM and MSR suggests that simultaneous improvement of high carcass yield and beef marbling is possible. Estimated genetic correlations of RFI (RFIphe and RFIgen) of sires with CWT (− 0.60 and − 0.53) and MSR (− 0.62 and − 0.50) of their progeny were favorably negative indicating that the selection against RFI of sires may have contributed to produce heavier carcass and increase in beef marbling. The correlated responses in CWT, REA and RBT of progeny were higher to selection against RFI than those to selection against FCR of sires. This study provides evidence that selection against RFI is preferred over selection against FCR in sire population for getting better correlated responses in carcass traits of their progeny.
(6-June-2006)
 

Evans, R.D., Wallace, M., Garrick, D.J., Dillon, P., Berry, D.P., Olori, V. 2006. "Effects of calving age, breed fraction and month of calving on calving interval and survival across parities in Irish spring-calving dairy cows". Livestock Science, 100 (2-3): 216-230

KEYWORDS: Calving interval; Survival; Spring-calving; Holstein-Friesian; Age at first calving.

SUMMARY: The objective of this study was to investigate the effect of parity, age at calving, percentage North American Holstein-Friesian and calving date on subsequent calving interval and survival to facilitate the estimation of transition probabilities for month of calving. The economic value of traits that influence calving date, age distribution and survival can be assessed in models using a transition probability matrix. Such a matrix contains the probabilities that a cow of a particular age or breed calving in a particular month will calve in the same, an earlier or later month next year, or be culled. Following editing 1,046,855 calving records in spring-calving herds between the years 1990 and 2004 were analysed. Shorter calving intervals were associated with cows calving later in the calendar year. Age at first calving of < 24 months resulted in longer calving intervals to second calving across all levels of Holstein percentage with cows calving for the first time at 25–26 months of age having the shortest subsequent calving interval. Age at second calving of 37–38 months and third calving of 49–50 months were optimum for shorter subsequent calving intervals. Calving interval increased with Holstein percentage across the first 5 parities. Survival rate decreased with later month of calving and with older parities. When survival rate was measured as the ability of the cow to re-calve within 500 days, the highest survival rate was found in cows calving at 25–26 months of age whereas there was a noticeable reduction in survival across all parities in the 88–100% Holstein percent category.
(6-June-2006)
 

Ben Gara, A., Rekik, B., Bouallègue, M. 2006. "Genetic parameters and evaluation of the Tunisian dairy cattle population for milk yield by Bayesian and BLUP analyses". Livestock Science, 100 (2-3): 142-149

KEYWORDS: Milk yield; Bayesian estimation; BLUP; Genetic evaluation

SUMMARY: A Markov Chain Monte Carlo Bayesian method and BLUP analyses were used on Tunisian dairy cattle data. Data included 92,106 lactation records collected on 37,536 animals over 19 freshening years, from 1983 to 2001. Each record was partitioned into the fixed effects of herd-year, month of calving, and age-parity, a permanent environmental effect, an additive genetic effect, and a residual effect. Posterior conditional distributions were determined for variance components and model effects. Solutions (BLUE) and posterior means for levels of herd-year, month of calving, and age-parity showed similar patterns. Posterior means of heritability and repeatability were 0.17 ± 18 × 10− 5 and 0.39 ± 8 × 10− 5, respectively. Posterior means of bull's breeding values were compared to bull's BLUP solutions. BLUP solutions were obtained using 0.17 and 0.39, estimated from the data, and 0.25 and 0.40 estimates for heritability and repeatability, respectively. Rank correlations between bull's posterior means and BLUP breeding values were 0.998 and 0.994 using genetic parameters estimated from the data and from the literature, respectively. This correlation coefficient was 0.995 between bull's BLUP solutions using either of the two sets of genetic parameters.
(6-June-2006)
 

Zatoń-Dobrowolska, M., Čitek, J., Filistowicz, A., Řehout, V., Szulc, T. 2006. "An estimation of the genetic distance between Polish red and other red cattle breeds on the basis of selected milk protein loci". Electronic Journal of Polish Agricultural Universities, 9 (2): http://www.ejpau.media.pl/volume9/issue2/art-10.html

KEYWORDS: genetic distance, polymorphism, red cattle.

SUMMARY: The material for the study were six populations of Red Cattle, including three samples of the Polish Red cattle population (PC’69, n=203, PC’82, n=261 and PC’96, n = 313) and one each of the Danish Red (DC, n = 169), German Red (NC, n = 510) and Czech Red (CC, n = 14). DNA was isolated from blood samples. All individuals were genotyped for the following proteins: αS1-casein, β-casein, κ-casein and β-lactoglobulin. The frequency of alleles was estimate and was used for the estimation of the genetic distance between populations. Using the PHYLIP ver. 3.5c software the genetic distance was determined according to 1) Nei, 2) Cavali-Sforza and 3) Reynolds. All the populations demonstrated a similar distribution of allele frequencies at individual loci. Only the Czech Red showed different tendencies as regards β- and κ-casein and β-lactoglobulin. This may have been the effect of the smaller population size as compared to the remaining breeds. Genetic distances estimated by these three using methods were similar. The smallest genetic distance was observed between populations PC’96 and NC (0.0007). In turn, the highest value was obtained between population DC and CC (0.0776). In the case of the genetic distance calculated according to the formulas by Cavalli-Sforza and Reynolds, the values obtained were higher then value of genetic distance estimated by Nei. The comparatively low values for the genetic distance obtained in the present studies may indicate that the breeds analysed originate from a common ancestor or lived on neighboring geographical regions, what could lead to a frequent exchange of genes. The considerable similarity between those breeds could also be caused by a similarly conducted selection, based on similar assumptions (similar type of production). Those populations demonstrate similar gene pools what may be used for common preserve breeding programmes, which would decrease the danger of inbreeding. An analysis of the data collected over 30 years for the three populations of the Polish Red cattle, renders it possible to conclude that the frequency of individual alleles of the proteins examined are subjected to a small but continuous change.
(6-June-2006)
 

Mello, S. de P., Alencar, M.M., de Toral, F.L.B. 2006. "Estimates of genetic parameters for growth and productivity traits of Canchim cows using Bayesian inference". Revista Brasileira de Zootecnia, 35: 92-97.

KEYWORDS: beef cattle; body weight; days in herd; female productivity.

SUMMARY: The objective of this study was to estimate genetic parameters for body weights at weaning (PD), 12 months old (P12) and adult age (PAD), culling age (TPR, days in herd), number (ND10) and kilograms (QD10) of calves weaned up to ten years of age, total number (NDT) and total kilograms (QDT) of calves weaned during herd life, and kilograms of calves weaned per year in herd (QTPR) of Canchim (5/8 Charolais + 3/8 Zebu) females from one herd. Data consisted of 3,249, 3,111, 1,138, 1,340, 1,362, 1,362, 1,340, 1,340 and 1,340 records of PD, P12, PAD, TPR, ND10, QD10, NDT, QDT and QTPR, respectively. Variance and covariance components were estimated by bivariate analyses between PD, P12 and PAD and other production traits using Bayesian inference. The models included the additive direct, permanent environmental and residual random effects and the fixed effects year and month of birth or calving, calving age and age of the animal, depending on the trait. QD10, QDT and QTPR of each female were obtained by adjusting the weaning weights of calves for year and month of birth, sex and age of cow. Average of heritability estimates were 0.38 (PD), 0.40 (P12), 0.54 (PAD), 0.22 (TPR), 0.22 (ND10), 0.24 (QD10), 0.23 (NDT), 0.23 (QDT) and 0.32 (QTPR), indicating genetic variability to obtain response by selection. Genetic correlations between TPR (-0.02, 0.26 and -0.12), ND10 (0.04, 0.10 and -0.29), QD10 (0.37, 0.39 and -0.13), NDT (-0.03, 0.14 and -0.25), QDT (0.20, 0.33 and -0.16), QTPR (0.21, 0.28 and -0.19) and body weights (PD, P12 and PAD) suggest that selection of females based on weaning and 12-month body weights will not affect productivity. However, it may be decreased by increasing female adult body weight.
(6-June-2006)
 

Mostert, B.E., Theron, H.E., Kanfer, F.H.J., van Marle-Kaster, E. 2006. "Comparison of breeding values and genetic trends for production traits estimated by a Lactation Model and a Fixed Regression Test-day Model". South African Journal of Animal Science, 36 (2): 71-78.

KEYWORDS: breeding values, genetic trends, Test-day Model

SUMMARY: A comparison of breeding values and genetic trends of production traits from two models is made. One set of breeding values and trends was estimated by the September/October 2003 South African National Genetic Evaluation, using a Lactation Model (LM). The other set was obtained in the 2004 South African National Genetic Evaluation, using a Fixed Regression Test-day Model (TDM). This comparison is made for Ayrshire, Guernsey, Holstein and Jersey cows participating in the South African Dairy Animal Improvement Scheme. Specific differences between the two models were documented, with differences in statistical methodology and inclusion of test-day records of the first three parities in the TDM vs. only first lactation 305-day yields in the LM, as the main differences. Significant reranking of especially cows and unproven sires occurred between the models. Genetic trends of the TDM were not as steep as those from the LM, as the trait that was selected was first lactation yield, while the TDM trends reflect genetic progress over the first three parities.
(6-June-2006)
 

Muller, C.J.C., Cloete, S.W.P., Olivier, J.J., Botha, J.A. de Waal, H. 2006. "Heritability of live weight and condition score in a Holstein herd and correlations with milk traits–preliminary estimates". South African Journal of Animal Science, 36 (2): 79-88.

KEYWORDS: Heritability, live weight, condition score, Holstein

SUMMARY: Genetic and environmental parameters for live weight and condition score have been determined for Holstein cows. Genetic correlations with milk traits were also derived. Monthly records were modelled by cubic splines, while the direct, additive effects of animal and the temporary environment (defined as cow environmental effects within lactations) were fitted as random. Lactation number interacted with monthly trends in cow live weight. Cows lost weight in the early part of the lactation. This reduction in live weight was probably because of a loss in body reserves, as suggested by a lower condition score. Cows gained live weight towards the end of lactation. The ultimate live weight of cows increased with parity because of ongoing growth. The heritability (h²) estimate for live weight was high at 0.65 ± 0.04, albeit still within the expected range. Condition score had a medium h² of 0.24 ± 0.05. Genetic and phenotypic correlations of live weight with milk yield were positive, i.e. 0.19 ± 0.14 and 0.12 ± 0.05, respectively, while correlations of condition score with milk yield were negative, i.e. 0.42 ± 0.15 and -0.17 ± 0.04, respectively. Although live weight could be used as an indirect indicator of feed intake and efficiency of milk production, other body conformation traits could also be used. There is a need in the South African dairy industry for a selection index based on production parameters and some traits such as live weight, condition score or specific conformation traits. However, a large participation of animals in milk recording and measurement of such traits is a prerequisite for such developments.
(6-June-2006)
 

Maiwashe, A., Nephawe, K.A., van der Westhuizen, R.R., Mostert, B.E., Theron, H.E. 2006. "Rate of inbreeding and effective population size in four major South African dairy cattle breeds". South African Journal of Animal Science, 36 (1): 50-57.

KEYWORDS: inbreeding, population size, dairy cattle.

SUMMARY: Pedigree information on the registered South African Ayrshire (n = 47 116), Guernsey (n = 18 766), Holstein (n = 892 458) and Jersey (n = 314 403) breeds was analyzed to determine the rate of inbreeding and effective population sizes for the period 1960 to 2003. Inbreeding coefficients were calculated using the Animal Breeder’s Tool Kit. The mean inbreeding coefficients for 2003 were 2.02%, 2.04%, 2.30%, and 3.05% for the Ayrshire, Guernsey, Holstein and Jersey, respectively. The corresponding rates of inbreeding per year were 0.05%, 0.05%, 0.06%, and 0.07% indicating that inbreeding is accumulating at a slightly higher rate in Jersey compared to the other three breeds. However, the rates of inbreeding in the current study are still considerably lower than the acceptable rate of less than 0.5% per year. Estimates of effective population sizes were 148, 165, 137, and 108 for the Ayrshire, Guernsey, Holstein and Jersey, respectively. Results indicate that the impact of inbreeding on genetic variability is still minimal. However, the impact of inbreeding on phenotypic performance on traits of economic importance was not investigated in the current study and should therefore receive future consideration.
(6-June-2006)
 

Mostert, B.E., Theron, H.E., Kanfer, van Marle-Kaster, E. 2006. "Test-day models for South African dairy cattle for participation in international evaluations". South African Journal of Animal Science 2006, 36 (1), 58-69.

KEYWORDS: Test-day models, South African dairy cattle, international evaluations

SUMMARY: Variance components and breeding values of production traits and somatic cell score of South African Guernsey, Ayrshire, Holstein and Jersey breeds have been estimated using a multi-lactation repeatability test-day model, including tests of the first three lactations as repeated measures and fitting the permanent environmental effect across lactations. Multitrait evaluations were done for the production traits (milk, butterfat and protein) and single trait evaluations for somatic cell score. Heritability estimates were comparable with yield and somatic cell score estimates obtained by test-day models from other countries (17-24% for milk yield; 10-13% for butterfat yield; 14-19% for protein yield and 6-8% for somatic cell score). Proofs of qualifying sires were sent to the International Bull Evaluation Service (INTERBULL) for participation in the March 2005 test runs. Genetic correlations between South Africa and other participating countries, estimated by INTERBULL, compared well with those amongst the other participating countries. Trend validation tests were successful using this methodology for all traits and breeds except for somatic cell score of the Guernsey breed, due to insufficient data for this trait. South Africa can now participate in routine INTERBULL evaluations to obtain Multiple Across Country Evaluation (MACE) breeding values, using this methodology.
(6-June-2006)

Coffey, M. P., Hickey, J., Brotherstone, S. “Genetic Aspects of Growth of Holstein-Friesian Dairy Cows from Birth to Maturity”. Journal of Dairy Science. 89: 322-329

KEYWORDS: Growth, Dairy heifer, Genetic selection

SUMMARY:In general, genetic selection is applied after first calving to traits that manifest themselves during the animal’s productive life, mostly during the early part of productive life. This selection policy has had undesirable correlated responses in other economically important traits, such as health and fertility, and may also have had an effect on the growth of animals both during productive life and before first calving. In this study, we analyzed the growth trajectory of dairy heifers that had been selected for maximum production of combined fat and protein (measured in kg; select line) or for average production (control line) in the United Kingdom. Before first calving, these divergent lines were managed as a single group. Select line heifers grew faster than did control line heifers. They were also heavier at first calving, but by the end of 3 lactations, the lines were not significantly different in live weight. Selection primarily for yield and for other traits has led to heifers that grow faster and reach higher growth rates earlier in life. A genetic analysis of birth, weaning, and calving weights yielded heritability estimates of 0.53 (birth weight), 0.45 (weaning weight), and 0.75 (calving weight). Confidence intervals for the genetic correlations between the traits indicated that these BW traits are not under the same genetic control.
(10-March-2006)
 

Freeman, A. R., Bradley, D. G., Nagda, S., Gibson, J. P., Hanotte, O. 2006. "Combination of multiple microsatellite data sets to investigate genetic diversity and admixture of domestic cattle". Animal Genetics, 37 (1): 1-9.

KEYWORDS: Admixture, Bos indicus, Bos Taurus, diversity, microsatellite

SUMMARY: Microsatellite markers are commonly used for population genetic analyses of livestock. However, up to now, combinations of microsatellite data sets or comparison of population genetic parameters from different studies and breeds has proven difficult. Often different genotyping methods have been employed, preventing standardization of microsatellite allele calling. In other cases different sets of markers have been genotyped, providing differing estimates of population genetic parameters. In this study, these issues were addressed and a general two-step regression approach in cattle was illustrated using three different sets of microsatellite data, to combine population genetics estimates of diversity and admixture. This regression-based method is independent of the loci genotyped but requires common breeds in the data sets. It was shown that combining microsatellite data sets can provide new insights on the origin and geographical distribution of genetic diversity and admixture in cattle, which will facilitate global management of this livestock species.
(10-March-2006)
 

Sasaki, Y., Nagai, K., Nagata, Y., Doronbekov, K., Nishimura, S., Yoshioka, S., Fujita, T., Shiga, K., Miyake, T., Taniguchi, Y., Yamada, T. 2006. "Exploration of genes showing intramuscular fat deposition-associated expression changes in musculus longissimus muscle". Animal Genetics, 37 (1): 40-46.

KEYWORDS: Cattle, gene expression pattern, intramuscular fat deposition, musculus longissimus

SUMMARY: Marbling, as defined by the amount of intramuscular fat, is an economically important trait in beef cattle. Intramuscular fat deposition is postulated to arise mainly from a series of adipogenic events in intramuscular adipocyte-lineage cells and in the physiological or anatomical milieux surrounding them. This study was designed to investigate gene-expression patterns associated with fat deposition in musculus longissimus muscle, including adipocyte-lineage cells and part of the milieux. Differential-display PCR (ddPCR) was used to examine expression differences between low-marbled and high-marbled steer groups at 8, 10, 12 and 14 months of age, encompassing the time that marbling starts to appear. Seventy-four of 2114 total bands on ddPCR gel-bands were significant (P < 0.05) for the group effect, the interaction effect between group and age, or both the group and the interaction effects. Sequence analysis of 72 of these bands revealed 77 genes, including 35 annotated genes and 42 novel sequences. Among the 35 annotated genes, 6 (BTG2, PDHB, SORBS1, TRDN, TTN and MGP) have been related to changes in intramuscular fat deposition, possibly by exerting effects on adipocyte-lineage cells or on the milieux surrounding them.
(10-March-2006)

McGuire, K., Jones, M., Werling, D., Williams, J. L., Glass, E. J., Jann, O. 2006. "Radiation hybrid mapping of all 10 characterized bovine Toll-like receptors". Animal Genetics, 37 (1): 47-50.

KEYWORDS: Bos Taurus, radiation hybrid mapping, toll-like receptors

SUMMARY: Toll-like receptors (TLRs) are cell-surface signalling molecules that recognize a range of highly conserved pathogen molecules and instigate the appropriate immune response. The mapping of all 10 characterized bovine TLR genes using a radiation hybrid panel were reported. The genomic organization of the bovine TLRs is similar to that of humans and mice. TLR1, TLR6 and TLR10 map closely together on Bos taurus chromosome 6 (BTA6), while TLR7 and TLR8 map to the X chromosome. TLR2, TLR3, TLR4, TLR5 and TLR9 map to BTA17, BTA27, BTA8, BTA16 and BTA22 respectively. Our increased knowledge of the genomic organization of the bovine TLR genes may promote our understanding of their evolution and help in the identification of bovine genes underlying disease-resistance traits.
(10-March-2006)
 

Mizoguchi, Y., Watanabe, T., Fujinaka, K., Iwamoto, E., Sugimoto, Y. 2006. "Mapping of quantitative trait loci for carcass traits in a Japanese Black (Wagyu) cattle population". Animal Genetics, 37 (1): 51-54.

KEYWORDS: Carcass traits, cattle, half-sib family, Japanese Black, quantitative trait loci

SUMMARY: To detect quantitative trait loci (QTL) that influence economically important traits in a purebred Japanese Black cattle population, a preliminary genome-wide scan was performed using 187 microsatellite markers across a paternal half-sib family composed of 258 offspring. Six QTL at the 1% chromosome-wise level were located on bovine chromosomes (BTA) 4, 6, 13, 14 and 21. A second screen of these six QTL regions using 138 additional paternal offspring half-sib from the same sire, provided further support for five QTL: carcass weight on BTA14 (22–39 cM), one for rib thickness on BTA6 (27–58 cM) and three for beef marbling score (BMS) on BTA4 (59–67 cM), BTA6 (68–89 cM) and BTA21 (75–84 cM). The location of QTL for subcutaneous fat thickness on BTA13 was not supported by the second screen (P > 0.05). The combined contribution of the three QTLs for BMS was 10.1% of the total variance. The combined phenotypic average of these three Q was significantly different (P < 0.001) from those of other allele combinations. Analysis of additional half-sib families will be necessary to confirm these QTL.
(10-March-2006)
 

Abbasi, A. R., Geriletoya, , Ihara, N., Khalaj, M., Sugimoto, Y., Kunieda, T. 2006. "An integrated radiation hybrid map of bovine chromosome 18 that refines a critical region associated with multiple ocular defects in cattle". Animal Genetics, 37 (1): 58-61.

KEYWORDS: BTA18, cattle, comparative map, eye anomaly, radiation hybrid map

SUMMARY: Congenital multiple ocular defects (MOD) of Japanese black cattle is a hereditary ocular disorder with an autosomal recessive mode of inheritance showing developmental defects of the lens, retina and iris, persistent embryonic eye vascularization and microphthalmia. The MOD locus has been mapped by linkage analysis to a 6.6-cM interval on the proximal end of bovine chromosome 18, which corresponds to human chromosome 16q and mouse chromosome 8. To refine the MOD region in cattle, we constructed an integrated radiation hybrid (RH) map of the proximal region of bovine chromosome 18, which consisted of 17 genes and 10 microsatellite markers, using the SUNbRH7000 panel. Strong conservation of gene order was found among the corresponding chromosomal regions in cattle, human and mouse. The MOD-critical region was fine mapped to a 59.5-cR region that corresponds to a 6.3-Mb segment of human chromosome 16 and a 4.8-Mb segment of mouse chromosome 8. Several positional candidate genes, including FOXC2 and USP10, were identified in this region.
(10-March-2006)
 

Altarriba, J. Varona, L., Moreno, C., Yagüe, G., Pastor, F. 2006. "Effect of growth selection on morphology in Pirenaica cattle". Animal Research, 55: 55-63

KEYWORDS: Indirect response, morphology, growth, weight to 210 days, cattle

SUMMARY: Twelve variables were identified to define morphology in 109 calves sired by eight Pirenaica bulls widely used in artificial insemination. The effect of selection for weight at 210 days of age (W210) was detected from the regression coefficient between the 12 variables and the selection index for W210 used in the breeding plan. Unbiased estimates of the genetic correlated responses on the morphology were obtained without previously estimating the genetic correlation among traits. In Pirenaica cattle, selection for W210 increased slaughter live weight, chest depth and corporal length. The expected changes on height (withers, back and rump), rump width and thoracic perimeter were lower but positive and statistically significant.
(10-March-2006)
 

Silva, B., Gonzalo, A., Cañón, J. 2006. "Genetic parameters of aggressiveness, ferocity and mobility in the fighting bull breed" Animal Research, 55: 65-70.

KEYWORDS: Cattle, behaviour traits, fighting ability, genetic parameters

SUMMARY: Genetic parameter estimates for Aggressiveness, Ferocity and Mobility in the fighting bull bovine breed were obtained using the restricted maximum likelihood (REML) methodology applied to a multiple trait animal model. The year of birth and the sex of the animal were the environmental fixed effects considered in the model. Genetic trends were determined from the average predicted breeding value over the year of birth. The behavioural traits considered showed an important additive genetic component which can be used to modulate the phenotype expression by selection. Heritability values around 0.3 (0.286-0.362) for all traits could explain the successful empirical selection carried out on the Aggressiveness trait. Similarly, the lack of genetic correlation (P > 0.05) between all traits explains the absence of a correlated response for the Ferocity and Mobility traits.
(10-March-2006)
 

Fuji, C., Suki, M. 2006. "Comparison of homogeneity and heterogeneity of residual variance using random regression test-day models for first lactation Japanese Holstein cows". Animal Science Journal, 77 (1): 28-32.

KEYWORDS: Genetic parameter, heterogeneous residual variance, Japanese Holstein, random regression test-day model

SUMMARY: Using a large-scale data set that included first lactation test day records from 1975 to 2000 for Japanese Holsteins, genetic parameters for milk yield were estimated by using random regression (RR) test-day models (TDM) with heterogeneous and homogeneous residual variances. It is necessary for the RR-TDM to include a function that explains the shape of the lactation curve. The RR-TDM with the LW curve, which combined Wilmink's curve and a Legendre polynomial, was used for fitting the model for milk yield. In recent years, increases in residual variance have been noted for Japanese dairy cattle. Thus, three kinds of heterogeneous residual variance over the calving year were considered: H1, H2 and HG. Linear and quadratic exponential functions for the calving year were used in H1 and H2, respectively. Residual variance of HG was divided into five groups according to calving year. Homogeneous residual variance was HO. All heterogeneous residual variances increased with calving year in an almost linear fashion. Residual variance increased over the study period. However, there is no need to consider heterogeneous residual variances in genetic evaluations, because the heterogeneity of residual variance over the years did not affect the ranking of top sires and cows.
(10-March-2006)
 

Graphodatskaya, D., Joerg, H., Asai-coakwell, M., Janett, F., Snger, G. 2006. "Expression and function of agouti signaling protein in cattle". Animal Science Journal, 77 (1): 33-41.

KEYWORDS: Agouti signaling protein, cattle, cyclic adenosine monophosphate, melanocortin 1 receptor, real-time polymerase chain reaction

SUMMARY: Agouti signaling protein (ASIP) is involved in the regulation of pigmentation in mammals by downregulating melanocortin 1 receptor (MC1R) activity. In wild type mice, ASIP is expressed in skin and testes. Widespread tissue expression of ASIP has been found in humans and cattle. Reverse transcription with subsequent real-time polymerase chain reaction was used to measure ASIP expression levels in skin and five additional tissues from four cattle breeds. The expression of each sample was represented as a percentage of the expression of the housekeeping gene b-actin. No significant difference was found in the expression levels in skin from Red Holstein, Simmental (red), Holstein (black) and Brown Swiss (brown/gray) breeds, which were all in the range of 0.2–0.3%. Expression in other tissues varied greatly between individuals, ranging from 196% in the heart of a Red Holstein animal to 0% in the liver samples of all four breeds. Additionally, expression of bovine ASIP in cell culture reduces cyclic adenosine monophosphate production in cells expressing MC1R, suggesting that bovine agouti is able to downregulate MC1R signaling.
(10-March-2006)
 

Khalaj, M., Abbasi, A.R., Tsuji, T., Moritomo, Y., Shimojo, K., Kunieda, T. 2006. "Polymerase chain reaction-restriction fragment length polymorphism method for identifying carriers of hemophilia A in Japanese brown cattle". Animal Science Journal, 77 (1): 122-125.

KEYWORDS: Bleeding disorder, factor VIII, hemophilia A, Japanese brown cattle, polymerase chain reaction-restriction fragment length polymorphism

SUMMARY: Hemophilia A is a severe congenital bleeding disorder characterized by subcutaneous hematoma and hemorrhage into muscles resulting from a deficiency of blood coagulation factor VIII. The authors have recently reported two cases of hemophilia A in Japanese Brown cattle and identified a nucleotide substitution in the factor VIII gene, resulting in an amino acid substitution of Leu to His, as a possible cause of the deficiency. In the present study, a simple and effective polymerase chain reaction (PCR)-based diagnostic method was developed to identify carriers of this disorder, using a mismatch primer in combination with restriction enzyme digestion. The PCR reaction amplified a 118 bp fragment, which was not digested by the BspT104I restriction enzyme in affected animals but was digested into two fragments in normal animals. Both digested and undigested fragments were observed in carrier animals. This method was applied to identify the carriers of hemophilia A in a population of Japanese Brown cattle. By screening 155 DNA samples from Japanese Brown cattle, except for the dam of the two probands, no carriers were identified. It was therefore concluded that the probands represent isolated cases of hemophilia A, and that the frequency of the mutant allele in the Japanese Brown cattle population is very low.
(10-March-2006)
 

Hinrichs, D., Stamer, E., Junge, W., Kalm, E. 2006. "Genetic Analysis of Several Disease Categories Using Test Day Threshold Models in German Holstein Cows". Archiv für Tierzucht, 49 (1): 3-16

KEYWORDS: Disease, Test Day Threshold Models, German Holstein, heritability

SUMMARY: In the present study trajectories for the disease categories udder diseases, metabolic diseases, all diseases, fertility diseases, and ovarian problems, are described. Variance components were estimated where the considered period of lactation varies between 50 and 300 days. Furthermore, the impact of the number of daughters per sire was analysed with disease information from the first 50 days of lactation. In total 18 data sets were analysed with a test day threshold model. The average disease frequencies were between 6.5% and 2.7% for udder diseases and they were between 1.7% and 0.4%, and 15.3% and 6.0% for metabolic diseases and ‘all diseases’, respectively. For udder diseases the estimated heritabilities vary between 0.12 and 0.25 depending on lactation length and the number of daughters per sire. For metabolic disease heritabilities were estimated within the interval of 0.12 to 0.24. Depending on the lactation length the heritabilities of all diseases were fairly constant (0.03 to 0.04). The heritabilities of all diseases increased if fertility diseases were excluded. Those estimates vary between 0.15 to 0.19.
(10-March-2006)
 

Bojarojc-Nosowicz, B., Kaczmarczyk, E. 2006. "Somatic cell count and chemical composition of milk in naturally BLV-infected cows with different phenotypes of blood leukocyte acid phosphatase". Archiv für Tierzucht, 49 (1): 17-28

KEYWORDS: Somatic cell count, blood leukocyte acid phosphatase, cattle

SUMMARY: Effectiveness of the methods applied to control mastitis is low. Therefore, indices are sought which could improve cow immunity to udder pathogens. The aim of the study was to determine the relationship between the polymorphism of blood leukocyte acid phosphatase (AcP), BLV infection, the somatic cell counts and the milk composition in the first trimester of lactation. Studies were performed on a population of 65 Black-and-White cows, aged 3-6 years, from a leukemia-dominated herd. Enzootic bovine leukemia was diagnosed with ELISA and PCR tests. The following analyses were performed: the contents of total protein, lactose, dry matter, somatic cell count in milk as well as microbiological analyses. The obtained results indicate the occurrence of an association between a natural BLV-infection and mammary gland secretion disturbances in cows, whereas the relationship with the acid phosphatase polymorphism is not explicit. The obtained results encourage the continuation of studies into the role of blood leukocytes AcP in the pathogenesis of mastitis.
(10-March-2006)
 

Pöhland, R., Lenz, S., Vanselow, J., Tomek, W. 2006. "Detection of gene expression and enzyme activity of Cytochrom P450 arom (aromatase) in preantral and early antral bovine follicles depending on culture conditions in vitro". Archiv für Tierzucht, 49 (1): 29-40

KEYWORDS: Cytochrom P450 arom, bovine follicles

SUMMARY: This study reveals that cultivation of preantral and early antral (< 500 µm) follicles in culture medium containing FCS results in an expression of cytochrome P450 arom. (aromatase). The enzymatic activity of aromatase, measured in terms of the estradiol synthesis, was proved to be present in follicles greater than 100 µm, could further be stimulated by FSH in follicles greater than 300 µm diameter. The enzyme protein and the gene expression were studied by means of western blot and immunohistochemistry as well as by means of realtime PCR. Neither the protein nor the corresponding mRNA could be found in uncultivated follicles and in FCS-free cultivated follicles. Estradiol synthesis could not be determined under FCS-free conditions. The expression of the FCS effect was dependent on the follicle size.
(10-March-2006)
 

Garnero, A., Del V., Marcondes, C.R., Bezerra, L.A.F. 2006. "Genetic parameters of maturation rate and asymptotic weight of Nelore females". Arquivos da Escola Veterinária da Universidade Federal de MInas Gerais, 57: 652-662.

KEYWORDS: bovine, asymptotic weight, growth rate, growth curves

SUMMARY: Data from 1158 females Nellore beef cattle, born between 1984 and 1995, at 10 breeding farms and located at seven differents States of Brazil were used to establish a growth pattern curve of beef cattle females, and to estimate variance components, heritabilities and genetic correlations between the parameters for Von Bertalanffy, Brody, logístic and Gompertz models. The NLIN procedure and the MTDFREML program under animal model were used for single and two trait analyses. The average weight (A) and growth rate (K) were 515.06 and .071 for Von Bertalanffy, 552.77 and .045 for Brody, 501.11 and .097 for logistic, and 507.00 and .083 for Gompertz, respectively. High heritabilities were estimated for A and K parameters: .39 and .42 for Von Bertalanffy, .42 and .44 for Brody, .40 and .41 for logistic, and .39 and .39 for Gompertz, respectively. All the models described adequately the growth pattern of those females. The best model to describe the growth curve based on the number of iteractions for convergence, error mean square and the coefficient of determination was Brody model, followed by Von Bertalanffy, logistic and Gompetz models. These characteristics (A and K parameters) could be included in selection index for female Nelore selection.
(10-March-2006)
 

Fridrich, A.B., Silva, M.A., Fridrich, D. 2006. "Genotype by environment interaction and genetic parameter estimates for growth traits of Tabapuã cattle". Arquivos da Escola Veterinária da Universidade Federal de MInas Gerais, 57: 663-672.

KEYWORDS: bovine, Tabapuã breed, direct and maternal heritability, genotype-environment interaction, growth trait.

SUMMARY: Body weight records at 205 (205BW) and 365 (365BW) days of age of 28,946 Tabapuã animals born during the 1976-1995 period from 152 Tabapuã herds of several states of Brazil, were used to evaluate genotype by environment interactions and to estimate genetic and maternal heritability by restricted maximum likelihood methodology. The statistical model included the fixed effects of contemporary group and age of cow (covariate), and the random additive genetic and maternal effects. Maternal and genetic heritability estimates for BW205 considered as different traits in each of the South (R1), Southeast (R2), Central West (R3), Northeast (R4) regions were .02 and .31, .17 and .19, .20 and .09 and .06 and .16, respectively, and for BW365 they were .05 and .03 (R1), .20 and .03 (R2), .51 and .62 (R3) and .15 and .05 (R4). The genetic correlation for 205BW and 365BW both considered as different traits in each of the South (R1), Southeast (R2), Central West (R3), Northeast (R4) regions were, respectively, 1.00 and .99, .84 and .99, -.86 and -.73, .98 and .93, .51 and .45, 1.00 and .12 for BW205 and BW365 in R1/R2, R1/R3, R1/R4, R2/R3, R2/R4 e R3/R4, respectively, indicating a significant genotype by environment interaction for 205BW only for the combination between Northeast and the South and Southeast regions. For the 365BW there was a significant genotype by environment interaction for all combinations involving the Northeast region.
(10-March-2006)
 

Peixoto, M.G.C.D., Pereira, C.S., Fonseca, C.G. 2006. "Selection to milk production in Zebu MOET nuclei: a simulation study". Arquivos da Escola Veterinária da Universidade Federal de MInas Gerais, 57: 673-683.

KEYWORDS: MOET nucleus, genetic gain, inbreeding, simulation.

SUMMARY: A stochastic genetic simulation of adult MOET breeding nucleus schemes was carried out. A finite panmitic population with discrete generation and selection for a trait under an infinitesimal model were assumed. The heritabilities of .25, .35 and .45 and the repeatability of .50 were considered. Different population sizes (N), mating strategies (A), number of MOET progenies (P) and number of sires selected from full sib family (R) used in the definition of the nucleus scheme were evaluated. Population sizes were of 16 donors/8 sires, 16 donors/4 sires and 32 donors/4 sires. Mating strategies were hierarchical (H) - each donor was mated to only one sire, factorial I (F-I) - each donor was mated to two sires, and factorial II (F-II) - each donor was mated to four sires. The number of MOET progenies from each donor by superovulation was 4 or 8. The number of selected sires from each full sib family was 1 or 2. Generation interval (IG) of 3.89 years was used whatever the mating strategy evaluated and the IG of 4.15 was also used when the F-II mating strategy was evaluated. All factors evaluated affected significantly (P<0.05) the genetic gain for all heritabilities considered. Interactions between N×A, N×R and P×A were also significant (P<0.05). The interaction A×R had a significant effect (P<0.05) only for heritabilities of .25 and .35. All factors studied for all heritability values had a significant effect (P<0.05) on the inbreeding rate. The N×P, N×A, N×R and P×A interactions had also a significant effect (P<0.05) on the inbreeding rate. It was strengthened that the MOET efficiency in producing viable embryos and positive pregnancies, besides the degree of reduction in IG, are responsible for the genetic progress rate in the MOET selection nucleus schemes.
(10-March-2006)
 

Reist-Marti, S.B., Abdulai, A., Simianer, H. 2006. "Optimum allocation of conservation funds and choice of conservation programs for a set of African cattle breeds". Genetic Selection Evolution, 38: 99-126.

KEYWORDS: optimal allocation, conservation program, African cattle, conservation funds, choice of program

SUMMARY: Although funds for livestock conservation are limited there is little known about the optimal allocation of conservation funds. A new algorithm was used to allocate Mio US$ 1, 2, 3, 5 or unlimited funds, discounted over 50 years, on 23 African cattle breeds conserved with four different possible conservation programs. Additionally, Mio US$ 1 was preferably allocated to breeds with special traits. The conceptional in situ conservation programs strongly involve breeders and give them part of the responsibility for the conservation of the breed. Therefore, the pure in situ conservation was more efficient than cryoconservation or combined in situ and cryoconservation. The average annual discounted conservation cost for a breed can be as low as US$ 1000 to US$ 4400 depending on the design of the conservation program and the economic situation of the country of conservation. The choice of the breeds and the optimal conservation program and the amount of money allocated to each breed depend on many factors such as the amount of funds available, the conservation potential of each breed, the effects of the conservation program as well as its cost. With Mio US$ 1, 64% of the present diversity could be maintained over 50 years, which is 13% more than would be maintained if no conservation measures were implemented. Special traits could be conserved with a rather small amount of the total funds. Diversity can not be conserved completely, not even with unlimited funds. A maximum of 92% of the present diversity could be conserved with Mio US$ 10, leaving 8% of the diversity to unpredictable happenings. The suggested algorithm proved to be useful for optimal allocation of conservation funds. It allocated the funds optimally among breeds by identifying the most suited conservation program for each breed, also accounting for differences in currency exchange rates between the different countries.
(10-March-2006)
 

Gautier, M, Barcelona, R.R., Fritz, S., Grohs, C., Druet, T., Boichard, D., Eggen, A., Meuwissen, T.H.E. 2006. "Fine Mapping and Physical Characterization of Two Linked Quantitative Trait Loci Affecting Milk Fat Yield in Dairy Cattle on BTA26". Genetics, 172: 425-436.

KEYWORDS: Fine Mapping, Linked Quantitative Trait Loci, Milk, Fat, Dairy cattle.

SUMMARY: Previously, a highly significant QTL affecting fat yield and protein yield and mapped to the bovine BTA26 chromosome has been reported to segregate in the French Holstein cattle population. To confirm and refine the location of this QTL, the original detection experiment was extended by adding 12 new families and genotyping 25 additional microsatellite markers (including 11 newly developed markers). Data were then analyzed by an approach combining both linkage and linkage disequilibrium information, making it possible to identify two linked QTL separated by 20 cM corresponding to 29 Mb. The presence of a QTL affecting protein yield was confirmed but its position was found to be more telomeric than the two QTLunderlying fat yield. Each identified QTL affecting milk fat yield was physically mapped within a segment estimated to be <500 kb. Two strong functional candidate genes involved, respectively, in fatty acid metabolism and membrane permeability were found to be localized within this segment while other functional candidate genes were discarded. A haplotype comprising the favorable allele at each QTL position appears to be overrepresented in the artificial insemination bull population.
(10-March-2006)
 

Negrini, R., Milanesi, E., Bozzi, R., Pellecchia, M., Ajmone-Marsan, P. 2006. "Tuscany autochthonous cattle breeds: an original genetic resource investigated by AFLP markers". Journal of Animal Breeding and Genetics, 123 (1): 10-16.

KEYWORDS: Tuscany autochthonous, cattle breeds, AFLP markers

SUMMARY: The aim of this study was to assess the genetic diversity of four autochthonous cattle breeds of Tuscany and their relationships in comparison with Italian Friesian and Italian Brown, using amplified fragment length polymorphism markers. A total of 212 individuals were genotyped with three primer combinations generating 102 polymorphic markers. Average expected heterozygosity ranged from 0.23 in Mucca Pisana to 0.26 in Chianina, Italian Friesian, Italian Brown and Maremmana. The differences resulted not significant (Kruskall–Wallis test, p = 0.416). Gst-B index revealed that 86% of the total genetic variance is retained within population and only 14% is accounted by the between populations component. Multivariate analysis at individual and population level indicated that: (i) Calvana and Chianina are quite separate from the other breeds as an effect of the bottleneck experienced or as a signature of different origin; (ii) Podolian, Maremmana and Italian Brown clustered with the double purpose Mucca Pisana, revealing their contribution to its admixed genetic make up; (iii) Italian Friesian behaved always as out group. The 'analysis of molecular variance' recovered a significant subdivision clustering the six populations into three groups: Italian Friesian and Italian Brown versus Maremmana and Mucca Pisana versus Chianina and Calvana (6% of the total variance).
(10-March-2006)
 

Rewe, T.O., Indetie, D., Ojango, J.M.K., Kahi, A.K. 2006. "Economic values for production and functional traits and assessment of their influence on genetic improvement in the Boran cattle in Kenya". Journal of Animal Breeding and Genetics, 123 (1): 23-36.

KEYWORDS: Economic values, production traits, functional traits, Boran cattle

SUMMARY: Economic values for production (sale weight in steers, SWs, kg and heifers, SWh, kg; dressing percentage, DP; consumable meat percentage, CMP and milk yield, MY, kg) and functional (cow weight, CoWT, kg; cow survival rate, CoSR, %; postweaning survival rate, PSR, %; feed intake of cows, FIc, heifers, FIh and steers, FIs, kg DM) traits were estimated for six production systems utilizing the Boran breed in Kenya. The influence of the estimated economic values on genetic improvement was also assessed using different selection indices. The six production systems were described according to their sale age, levels of input and final goal, namely, short-fed medium input beef (SMB); long-fed medium input beef (LMB); short-fed high input beef (SHB); long-fed high input beef (LHB); long-fed low input dual purpose (LLD); and long-fed medium input dual purpose (LMD). Two evaluation bases were considered: fixed herd size and fixed pasture input. In the fixed herd-size situation, the economic values for production (except MY in beef systems) and functional traits (except FI in all systems) were positive meaning a unit increase in genetic merit of these traits had greater influence on revenues than costs. As expected, the economic value for MY was negative in the pure beef systems (SMB, LMB, SHB and LHB) and positive in the dual-purpose systems (LLD and LMD). When compared with the economic values estimated in the fixed herd-size situation, in the fixed pasture input situation they were lower for feed intake in the three classes of livestock and other traits related to it in all systems. These traits were CoSR, CoWR, PSR, CoWT, SWh and MY. The economic values for CoWT in LLD and LMD were negative (KSh −11.14 and −15.33 respectively). The economic values did not influence much the direction of the genetic response in each trait in the different production systems. However, the magnitude of the actual gain was dependent on the index applied. The magnitude of the economic values for production and functional traits estimated in this study suggest that genetic improvement of these traits will have a positive effect on profitability of Boran cows kept in dual-purpose systems and when herd size is restricted. In beef systems, genetic improvement of MY will have a negative effect on profitability, especially when restrictions on herd size and feed exists.
(10-March-2006)
 

Magaña, J.G., Segura-Correa, J.C. 2006. "Body weights at weaning and 18 months of Zebu, Brown Swiss, Charolais and crossbred heifers in south-east Mexico". Journal of Animal Breeding and Genetics, 123 (1): 37-43.

KEYWORDS: Body weight, cattle,

SUMMARY: The objective of this study was to evaluate the body weights up to 18 months of age of 12 breed groups of Zebu (Z), Brown Swiss (BS) and Charolais heifers (CH), and their crosses under tropical conditions. A total of 1434 data on weaning weights adjusted to 240 days (WW8), average daily gain to 240 days (ADG8) and 1025 body weights adjusted to 550 days (BW18) and average postweaning daily gain (ADG18) of heifers born from 1981 to 1995 were used. Cows and calves remained together from birth to weaning and grazed on Guinea grass (Panicum maximum). Years of birth were grouped in three periods, because of the small numbers of observations per year (1981–85, 1986–90 and 1991–95). Similarly, months of birth were grouped in three seasons: dry (February to May), rainy (June to September) and windy and rainy (October to January). Ages of dams were classified in six groups (≤3, 4, 5, 6, 7 and ≥8 years). Breed groups were animals with 12.5%, 25.0%, 50.0%, 62.5%, 75.0% and 100% BS genes and 25.0%, 50.0%, 75.0% and 100% CH genes and also Z and undefined crossbred animals. Data were analysed using a fixed model that included effects of period, and season of birth, age of dam and breed group of heifer. Analyses of variance showed significant (p < 0.05) effects of period, season and breed group for all traits. However, parity was significant (p < 0.05) only for WW8 and ADG8. Interactions among main factors were not significant (p > 0.05). Z heifers gained the least weight to weaning but were similar to BS at 18 months of age. CH were heavier at 18 months of age than BS heifers, but not at weaning. Body weights at 18 months of age of 1/8 and 1/4 BS crossbred heifers were similar (p > 0.05) and lower than F1 (BS × Z) (p < 0.05); however, the later and higher grades of BS had the highest body weights at 18 months of age and were similar to CH and 1/4 CH × 3/4 Z heifers. Undefined crossbred heifers had better performance than the Z breed group. Environmental factors were important sources of variation for pre- and postweaning traits. Under the conditions of this study, crossbred heifers generally performed better than Z heifers up to 18 months of age.
(10-March-2006)
 

Nishida, A., Aziz, M.A., Nishida, S., Suzuki, K. 2006. "Modelling number of services per conception of Japanese Black cattle by random regression". Journal of Animal Breeding and Genetics, 123 (1): 56-63.

KEYWORDS: Number of services per conception, random regression, cattle.

SUMMARY: Repeated records of number of services per conception (NSC) were collected on 607 Japanese Black cows. Data were analysed by random regression (RRM) and multiple trait (MTM) models, considering NSC in each parity as a separate trait. The chosen RRM included additive genetic and permanent environmental effects fitted with a third-order Legendre polynomials of parity. Heritabilities (h2) estimated by RRM decreased along the NSC trajectory from 0.15 in the first parity to 0.04 in the sixth parity and then increased up to 0.22 in the 10th parity. The corresponding estimates obtained by MTM ranged between 0.04 in parity 9 and 0.13 in parity 1. Permanent environmental proportions (p2) of the total phenotypic variance estimated by RRM showed similar pattern and magnitude to those of h2 estimated by the same method. On the contrary, the p2 estimated by MTM ranged between 0.04 in the first parity and 0.11 in the 10th parity. Additive genetic (rG), permanent environmental (rP) and phenotypic (rPH) correlations were also estimated. The values estimated by RRM between adjacent parities were higher than those of parities far apart. The corresponding values estimated by MTM were lower than those estimated by RRM with no certain trend. The results indicated that NSC in heifers is more heritable than NSC in cows with different parities. Reproductive traits are economically important traits and hence, they should be considered in breeding goals.
(10-March-2006)
 

Pereira, E., Oliveira, H.N., Eler, J.P., Silva, J.A. II de V., Melis, M.H. 2006. "Use of survival analysis as a tool for the genetic improvement of age at first conception in Nellore cattle". Journal of Animal Breeding and Genetics, 123 (1): 64-71.

KEYWORDS: survival analysis, age at first conception, genetic improvement, cattle.

SUMMARY: Restricted breeding seasons in beef cattle lead to censoring of reproductive data. In this paper, age at first conception (AFC) of Nellore females exposed to the sires for the first time between 11 and 16 months of age, was studied aiming to verify the possibility of genetically advance sexual precocity using a survival model. The final data set contained 6699 records of AFC in days. Records of females that did not calve in the next year following exposure to the sire were considered censored (77.5% of total). The model used was a Weibull mixed survival model including effects of contemporary groups, period (fixed) and animal (random). The effect of the contemporary groups on AFC was important (p < 0.01). Heritabilities were 0.51 and 0.76 in logarithmic and original scales respectively. Results indicate that it is possible to genetically advance sexual precocity, using the outcome of survival analysis of AFC as selection criterion. They also suggest that improvements of the environment could advance sexual precocity too, thus an adequate pregnancy rate for farmers could quickly be achieved.
(10-March-2006)
 

Crews, D. H., Jr. 2006. "Age of dam and sex of calf adjustments and genetic parameters for gestation length in Charolais cattle". Journal of Animal Science, 84: 25-31.

KEYWORDS: Beef cattle, Charolais, genetic parameter, gestation length

SUMMARY: To estimate adjustment factors and genetic parameters for gestation length (GES), AI and calving date records (n = 40,356) were extracted from the Canadian Charolais Association field database. The average time from AI to calving date was 285.2 d (SD = 4.49 d) and ranged from 274 to 296 d. Fixed effects were sex of calf, age of dam (2, 3, 4, 5 to 10, 11 yr), and gestation contemporary group (year of birth x herd of origin). Variance components were estimated using REML and 4 animal models (n = 84,332) containing from 0 to 3 random maternal effects. Model 1 (M1) contained only direct genetic effects. Model 2 (M2) was G1 plus maternal genetic effects with the direct x maternal genetic covariance constrained to zero, and model 3 (M3) was G2 without the covariance constraint. Model 4 (M4) extended G3 to include a random maternal permanent environmental effect. Direct heritability estimates were high and similar among all models (0.61 to 0.64), and maternal heritability estimates were low, ranging from 0.01 (M2) to 0.09 (M3). Likelihood ratio tests and parameter estimates suggested that M4 was the most appropriate (P < 0.05) model. With M4, phenotypic variance (18.35 d2) was partitioned into direct and maternal genetic, and maternal permanent environmental components ( = 0.64 ± 0.04, = 0.07 ± 0.01, rd,m = –0.37 ± 0.06, and c2 = 0.03 ± 0.01, respectively). Linear contrasts were used to estimate that bull calves gestated 1.26 d longer (P < 0.02) than heifers, and adjustments to a mature equivalent (5 to 10 yr old) age of dam were 1.49 (P < 0.01), 0.56 (P < 0.01), 0.33 (P < 0.01), and –0.24 (P < 0.14) d for GES records of calves born to 2-, 3-, 4-, and 11-yr-old cows, respectively. Bivariate animal models were used to estimate genetic parameters for GES with birth and adjusted 205-d weaning weights, and postweaning gain. Direct GES was positively correlated with direct birth weight (BWT; 0.34 ± 0.04) but negatively correlated with maternal BWT (–0.20 ± 0.07). Maternal GES had a low, negative genetic correlation with direct BWT (–0.15 ± 0.05) but a high and positive genetic correlation with maternal BWT (0.62 ± 0.07). Generally, GES had near-zero genetic correlations with direct and maternal weaning weights. Results suggest that important genetic associations exist for GES with BWT, but genetic correlations with weaning weight and postweaning gain were less important.
(10-March-2006)
 

Ciampolin, R., Cetica, V., Ciani, E., Mazzanti, E., Fosella, X., Marroni, F., Biagetti, M., Sebastiani, C., Papa, P., Filippini, G., Cianci, D. Presciuttini, S. 2006. "Statistical analysis of individual assignment tests among four cattle breeds using fifteen STR loci". Journal of Animal Science, 84: 11-19.

KEYWORDS: Assignment test, cattle breed, genetic diversity, microsatellite loci, statistical power

SUMMARY: Assignment tests based on multilocus genotypes are becoming increasingly important to certify quality and origin of livestock products and assure food safety and authenticity. The purpose of this study was to determine the potential of microsatellites (STR) for determining the breed origin of beef products among cattle breeds present in the market. We typed 19 STR in 269 animals from 4 cattle breeds. Based on Wright’s F-statistics, 4 loci were discarded, and the remaining 15 loci (FIT = 0.101, FST = 0.089, and FIS = 0.013) were used to compute the likelihood that each multilocus genotype of the total sample was drawn from its true breed instead of another breed. To avoid occurrence of zero likelihood when one or more alleles were missing from a tested breed, sample allele frequencies were estimated assuming uniform prior distributions. Log-likelihood ratio [log(LR)] distributions of the individual assignments were determined for all possible breed contrasts, and their means and SD were used to infer the true-positive and false-positive rates at several values of the log(LR). The posterior probability that the animals of a presumed breed were actually drawn from that breed instead of any another breed was then calculated. Given an observed value of log(LR) > 0 and assuming equal priors, these probabilities were >99.5% in 10 of 12 possible breed contrasts. For the 2 most closely related breeds (FST = 0.041), this probability was 96.3%, and the probability of excluding the origin of an animal from an alleged breed when it was actually derived from another breed was similar.
(10-March-2006)
 

Spangler, M. L., Sapp, R. L., Rekaya, R. Bertrand, J. K. 2006. "Success at first insemination in Australian Angus cattle: Analysis of uncertain binary responses". Journal of Animal Science, 84: 20-24.

KEYWORDS: Beef cattle, binary data, fertility, fuzzy logic, threshold model

SUMMARY: Field data from Australian Angus herds were used to investigate 2 methods of analyzing uncertain binary responses for success or failure at first insemination. A linear mixed model that included herd, year, and month of mating as fixed effects; unrelated service sire, additive animal, and residual as random effects; and linear and quadratic effects of age at mating as covariates was used to analyze binary data. An average gestation length (GL) derived from artificial insemination data was used to assign an insemination date to females mated to natural service sires. Females that deviated from this average GL led to uncertain binary responses. Two analyses were carried out: 1) a threshold model fitted to uncertain binary data, ignoring uncertainty (M1); and 2) a threshold model fitted to uncertain binary data, accounting for uncertainty via fuzzy logic classification (M2). There was practically no difference between point estimates obtained from M1 and M2 for service sire and herd variance; however, when uncertain binary data were analyzed ignoring uncertainty (M1), additive variance and heritability estimates were greater than with M2. Pearson correlations indicated that no major reranking would be expected for service sire effects and animal breeding values using M1 and M2. Given the results of the current study, a threshold model contemplating uncertainty is suggested for noisy binary data to avoid bias when estimating genetic parameters.
(10-March-2006)
 

Elzo, M. A., Rae, D. O., Lanhart, S. E., Wasdin, J. G., Dixon, W. P., Jones, J. L. 2006. "Factors associated with ELISA scores for paratuberculosis in an Angus-Brahman multibreed herd of beef cattle". Journal of Animal Science, 84: 41-48.

KEYWORDS: Beef cattle, Johne’s disease, multibreed, Mycobacterium avium subspecies paratuberculosis, paratuberculosis

SUMMARY: Cow and calf genetic and environmental factors were evaluated for their association with ELISA scores for paratuberculosis in a multibreed population of beef cattle. The ELISA scores are a measure of the presence or absence of antibodies against Mycobacterium avium subsp. paratuberculosis in bovine serum. The linear mixed-model analysis used 352 ELISA scores from 238 cows: 51 Angus (A); 34 Brahman (B); 41 (3/4 A ¼ B); 45 (1/2 A ½ B); 34 (1/4 A ¾ B); and 33 Brangus (5/8 A 3/8 B). Cows were assumed to be unrelated. Year affected (P < 0.001) ELISA scores, but age of cow did not, which was expected to be significant because of the chronic progressive nature of this disease. Important regressions on fixed effects associated with cows were 1) a positive estimate of cow B breed effect (0.59 ± 0.24; P < 0.017), indicating an upward trend of ELISA scores toward 100% B cows; 2) a negative estimate for weight change from before calving (late November) to the date of the blood sample in May (–0.0062 ± 0.0019 score/kg; P < 0.002), indicating that poorer maintenance of cow weights was associated with higher ELISA scores; and 3) a positive estimate for days in lactation of cow on the date of the blood sample (0.0086 ± 0.0034 score/d; P < 0.021), indicating the production of larger amounts of antibodies against Mycobacterium avium subsp. paratuberculosis as lactation progressed. Relevant regressions on fixed effects associated with calves were 1) calf birth weight (–0.022 ± 0.010 score/kg; P < 0.035), and 2) calf gain from birth to the date of the cow blood sample (–0.0092 ± 0.0027 score/kg; P < 0.001). These estimates indicate that cows that produced lighter calves at birth and/or calves with slower preweaning growth tended to have greater ELISA scores. Although the sensitivity (percentage of infected animals detected) of ELISA was only 50%, these results suggest that subclinical paratuberculosis may be negatively affecting cows and their offspring. Factors identified as associated with ELISA scores could help producers with culling decisions related to paratuberculosis control and eradication in beef cattle.
(10-March-2006)
 

Ríos-Utrera, A., Cundiff, L. V., Gregory, K. E. Koch, R. M., Dikeman, M. E., Koohmaraie, M., Van Vleck, L. D. 2006. "Effects of age, weight, and fat slaughter end points on estimates of breed and retained heterosis effects for carcass traits". Journal of Animal Science, 84: 63-87.

KEYWORDS: Beef cattle, breed effect, carcass trait, heterosis, slaughter end point

SUMMARY: The influence of different levels of adjusted fat thickness (AFT) and HCW slaughter end points (covariates) on estimates of breed and retained heterosis effects was studied for 14 carcass traits from serially slaughtered purebred and composite steers from the US Meat Animal Research Center (MARC). Contrasts among breed solutions were estimated at 0.7, 1.1, and 1.5 cm of AFT, and at 295.1, 340.5, and 385.9 kg of HCW. For constant slaughter age, contrasts were adjusted to the overall mean (432.5 d). Breed effects for Red Poll, Hereford, Limousin, Braunvieh, Pinzgauer, Gelbvieh, Simmental, Charolais, MARC I, MARC II, and MARC III were estimated as deviations from Angus. In addition, purebreds were pooled into 3 groups based on lean-to-fat ratio, and then differences were estimated among groups. Retention of combined individual and maternal heterosis was estimated for each composite. Mean retained heterosis for the 3 composites also was estimated. Breed rankings and expression of heterosis varied within and among end points. For example, Charolais had greater (P < 0.05) dressing percentages than Angus at the 2 largest levels of AFT and smaller (P < 0.01) percentages at the 2 largest levels of HCW, whereas the 2 breeds did not differ (P 0.05) at a constant age. The MARC III composite produced 9.7 kg more (P < 0.01) fat than Angus at AFT of 0.7 cm, but 7.9 kg less (P < 0.05) at AFT of 1.5 cm. For MARC III, the estimate of retained heterosis for HCW was significant (P < 0.05) at the lowest level of AFT, but at the intermediate and greatest levels estimates were nil. The pattern was the same for MARC I and MARC III for LM area. Adjustment for age resulted in near zero estimates of retained heterosis for AFT, and similarly, adjustment for HCW resulted in nil estimates of retained heterosis for LM area. For actual retail product as a percentage of HCW, the estimate of retained heterosis for MARC III was negative (–1.27%; P < 0.05) at 0.7 cm but was significantly positive (2.55%; P < 0.05) at 1.5 cm of AFT. Furthermore, for MARC III, estimates of heterosis for some traits (fat as a percentage of HCW as another example) also doubled in magnitude depending on different levels of AFT end point. Rational exploitation of breeds requires special attention to use of different end points and levels of those end points, mainly for fat thickness.
(10-March-2006)
 

Kealey, C. G., MacNeil, M. D., Tess, M. W.. Geary, T. W., Bellows, R. A. 2006. "Genetic parameter estimates for scrotal circumference and semen characteristics of Line 1 Hereford bulls". Journal of Animal Science, 84: 283-290

KEYWORDS: Beef cattle, fitness, semen, sperm morphology

SUMMARY: The objectives of this study were to estimate heritability for scrotal circumference (SC) and semen traits and their genetic correlations (rg) with birth weight (BRW). Semen traits were recorded for Line 1 Hereford bulls (n = 841), born in 1963 or from 1967 to 2000, that were selected for use at Fort Keogh (Miles City, MT) or for sale. Semen was collected by electroejaculation when bulls were a mean age of 446 d. Phenotypes were BRW, SC, ejaculate volume, subjective scores for ejaculate color, swirl, sperm concentration and motility, and percentages of sperm classified as normal and live or having abnormal heads, abnormal midpieces, proximal cytoplasmic droplets (primary abnormalities), bent tails, coiled tails, or distal cytoplasmic droplets (secondary abnormalities). Percentages of primary and secondary also were calculated. Data were analyzed using multiple-trait derivative-free REML. Models included fixed effects for contemporary group, age of dam, age of bull, inbreeding of the bull and his dam, and random animal and residual effects. Random maternal and permanent maternal environmental effects were also included in the model for BRW. Estimates of heritability for BRW, SC, semen color, volume, concentration, swirl, motility, and percentages of normal, live, abnormal heads, abnormal midpieces, proximal cytoplasmic droplets, bent tails, coiled tails, distal cytoplasmic droplets, and primary and secondary abnormalities were 0.34, 0.57, 0.15, 0.09, 0.16, 0.21, 0.22, 0.35, 0.22, 0.00 0.16, 0.37, 0.00 0.34 0.00, 0.30, and 0.33, respectively. Estimates of rg for SC with color, volume, concentration, swirl, motility, and percentages of live, normal, and primary and secondary abnormalities were 0.73, 0.20, 0.77, 0.40, 0.34, 0.63, 0.33, –0.36, and –0.45, respectively. Estimates of rg for BRW with SC, color, volume, concentration, swirl, motility, and percentages live, normal, and primary and secondary abnormalities were 0.28, 0.60, 0.08, 0.58, 0.44, 0.21, 0.34, 0.20, –0.02, and –0.16, respectively. If selection pressure was applied to increase SC, all of the phenotypes evaluated would be expected to improve. Predicted correlated responses in semen characteristics per genetic SD of selection applied to SC were 0.87 genetic SD or less. If selection pressure was applied to reduce BRW, the correlated responses would generally be smaller but antagonistic to improving all of the phenotypes evaluated. Predicted correlated responses in SC and semen characteristics per genetic SD of selection applied to BRW were less than 0.35 genetic SD.
(10-March-2006)
 

Schenkel, F. S., Miller, S. P., Jiang, Z., Mandell, I. B., Ye, X., Li, H., Wilton, and J. W. 2006. "Association of a single nucleotide polymorphism in the calpastatin gene with carcass and meat quality traits of beef cattle". Journal of Animal Science, 84: 291-299.

KEYWORDS: Beef breed, calpastatin gene, carcass trait, meat quality, single nucleotide polymorphism, tenderness

SUMMARY: Calpastatin (CAST) is a naturally occurring protein that inhibits the normal tenderization of meat as it ages postmortem. A SNP was identified in the CAST gene (a G to C substitution) and genotyped on crossbred commercially fed heifers (n = 163), steers (n = 226), and bulls (n = 61) from beef feedlots, and steers (n = 178) from a University of Guelph feeding trial. The association of the CAST SNP with carcass and meat quality traits was studied. Carcass traits included fat, lean, and bone yield; grade fat; LM area; and HCW. Meat quality traits included marbling grade; i.m. fat content of LM; tenderness evaluation of LM (Warner-Bratzler shear force) at 2, 7, 14, and 21 d of postmortem aging; and tenderness evaluation of semitendinosus muscle at 7 d of postmortem aging. The mixed model used in the analyses included fixed effects of CAST genotype, sex, slaughter group, and breed composition (linear covariate); sire was a random effect. For the analysis of shear force, i.m. fat content of LM was also included in the model as a linear covariate. Shear force measures were analyzed within days of postmortem aging and by repeated measures analysis. The CAST SNP allele C was more frequent (63%) in the crossbred population than allele G. The CAST SNP was associated with shear force across days of postmortem aging (P = 0.005); genotype CC yielded beef that was more tender than GG (–0.32 kg ± 0.13), and CG had intermediate tenderness. The corresponding average allele substitution effect (G to C substitution) was also highly significant (–0.15 ± 0.05 kg, P = 0.002). A lower percentage of unacceptably tough steaks (shear force >5.7 kg) at 2 and 7 d postmortem was associated with an increasing number of C alleles (P 0.05). At 7 d postmortem, the percentage of unacceptably tough steaks decreased by 24 and 35%, respectively, for animals carrying 1 and 2 copies of the C allele relative to animals with no C alleles. However, genotype CC had a greater fat yield (+1.44 ± 0.56%; P = 0.037) than genotype GG, with a corresponding allele substitution effect of 0.67 ± 0.27% (P = 0.015). Therefore, the CAST SNP allele C was associated with increased LM tenderness across days of postmortem aging and, importantly for the beef industry, had a significant reduction in the percentage of steaks rated unacceptably tough by consumers based on an assumed threshold level.
(10-March-2006)
 

Sasaki, Y., Miyake, T., Gaillard, C., Oguni, T., Matsumoto, M., Ito, M., Kurahara, T., Sasae, Y., Fujinaka, K., Ohtagaki, S., Dougo, T. 2006. "Comparison of genetic gains per year for carcass traits among breeding programs in the Japanese Brown and the Japanese Black cattle". Journal of Animal Science, 84: 317-323

KEYWORDS: Beef cattle, carcass trait, genetic trend, Japanese Black, Japanese Brown

SUMMARY: The breeding program for beef cattle in Japan has changed dramatically over 4 decades. Visual judging was done initially, but progeny testing in test stations began in 1968. In the 1980s, the genetic evaluation program using field records, so-called on-farm progeny testing, was first adopted in Oita, Hyogo, and Kumamoto prefectures. In this study, genetic trends for carcass traits in these 3 Wagyu populations were estimated, and genetic gains per year were compared among the 3 different beef cattle breeding programs. The field carcass records used were collected between 1988 and 2003. The traits analyzed were carcass weight, LM area, rib thickness, s.c. fat thickness, and beef marbling standard number. The average breeding values of reproducing dams born the same year were used to estimate the genetic trends for the carcass traits. For comparison of the 3 breeding programs, birth years of the dams were divided into 3 periods reflecting each program. Positive genetic trends for beef marbling standard number were clearly shown in all populations. The genetic gains per year for all carcass traits were significantly enhanced by adopting the on-farm progeny testing program. These results indicate that the on-farm progeny testing program with BLUP is a very powerful approach for genetic improvement of carcass traits in Japanese Wagyu beef cattle.
(10-March-2006)
 

Casas, E., Cundiff, L.V. 2006. "Postweaning growth and carcass traits in crossbred cattle from Hereford, Angus, Norwegian Red, Swedish Red and White, Friesian, and Wagyu maternal grandsires". Journal of Animal Science, 84: 305-310

KEYWORDS: Beef cattle, breed, carcass composition, growth

SUMMARY: The objective of this study was to characterize breeds representing diverse biological types for postweaning growth and carcass composition traits in terminal crossbred cattle. Postweaning growth and carcass traits were analyzed on 434 steers and 373 heifers obtained by mating F1 cows to Charolais sires. Maternal grandsires represented Hereford, Angus, and MARC III (1/4 Hereford, ¼ Angus, ¼ Pinzgauer, and ¼ Red Poll) dams to Hereford or Angus (British Breeds), Norwegian Red, Swedish Red and White, Wagyu, or Friesian breeds. Breed groups were slaughtered serially in each of 2 yr (2002 and 2003). Postweaning ADG, slaughter weight, hot carcass weight, dressing percentage, percentage Choice, LM area, marbling score, USDA yield grade, fat thickness, retail product yield (percentage), retail product weight, fat yield (percentage), fat weight, bone yield (percentage), and bone weight were analyzed. Maternal grandsire breed was significant (P < 0.05) for all traits except dressing percentage, percentage Choice, and LM area. Marbling score for animals with Norwegian Red, Wagyu, Swedish Red and White, British Breeds, and Friesian inheritance was 550, 544, 532, 530, and 515, respectively (SEM = 8). Retail product weight for these animals was 224, 211, 227, 223, and 223 kg, respectively (SEM = 2 kg). Maternal granddam breed was not significant for any of the traits analyzed. Grandsire breed effects can be optimized by selection and use of appropriate zcrossbreeding systems.
(10-March-2006)
 

Adamec, V., Cassell, B. G., Smith, E. P., Pearson, R.E. 2006. "Effects of Inbreeding in the Dam on Dystocia and Stillbirths in US Holsteins". Journal of Dairy Science, 89: 307-314.

KEYWORDS: Threshold model, inbreeding depression, dystocia, stillbirth

SUMMARY: Dystocia scores were recorded by producers on 120,434 Holsteins (218,213 records) from 1985 through 1996; dystocia scores 3 to 5 were coded as difficult births. Stillbirths were recorded for deaths within the first 48 h after birth. Data were restricted to registered cows for pedigree completeness, and inbreeding coefficients were calculated using 5-generation pedigrees. Computational restrictions required that subsets of the data be created by choosing herds at random but using all records from selected herds. Effects of inbreeding in the dam were estimated in a sire-maternal grandsire (of the calf) threshold model using Gibbs sampling. The model included fixed effects of calf sex and inbreeding of the dam and random effects of herd-year-season of birth, additive genetic, and residual effects. First, second, and third parities were analyzed separately. Solutions for sex of calf and inbreeding from different parities were converted to expected change in probability of dystocia or stillbirth per 1% increase in inbreeding. Inbreeding effects were largest for first-parity cows giving birth to male calves at a 0.42% increase in probability of dystocia/1% increase in inbreeding. Effects of inbreeding for first-parity dams giving birth to female calves were smaller, 0.30%/1% increase in inbreeding. Incidence of stillbirths increased 0.25 and 0.20% for male and female calves/1% increase in inbreeding for first parity births. Effects of inbreeding on dystocia and stillbirths declined with parity. Effects of inbreeding were small, especially in later parities, but were consistently unfavorable.
(10-March-2006)
 

Sanders, K., Bennewitz, J., Kalm, E. 2006. "Wrong and Missing Sire Information Affects Genetic Gain in the Angeln Dairy Cattle Population". Journal of Dairy Science, 89: 315-321.

KEYWORDS: Exclusion probability, genetic response, missing sire information, wrong sire information

SUMMARY: In the present study, molecular genetic markers were used to help estimate the degree of wrong sire information in the German Angeln dairy cattle population. Sixteen polymorphic microsatellite markers were genotyped on 5 different paternal half-sib families with a total of 805 daughters. For the genotyping process, blood samples of the daughters and semen samples of the sires were used. Allelic frequencies and exclusion probabilities were estimated. The simultaneous effect of wrong (WSI) and missing sire information (MSI) on the reliability of estimated breeding values and on the genetic gain was investigated using deterministic simulations. For these simulations, different values for the number of daughters per sire, heritability, WSI, and MSI were chosen. The estimated proportion of the WSI was 7% in the German Angeln dairy cattle population. The combined impact of WSI and MSI on the genetic gain was relatively large, especially in the case of small progeny size per sire and low heritability. The impact of WSI was more harmful than MSI on response to selection.
(10-March-2006)
 

Zwald, N. R., Weigel, K. A., Chang, Y. M., Welperand R. D., Clay, J. S. 2006. "Genetic Analysis of Clinical Mastitis Data from On-Farm Management Software Using Threshold Models". Journal of Dairy Science, 89: 330-336.

KEYWORDS: Clinical mastitis, genetic selection, threshold model, breeding value prediction

SUMMARY: Producer-recorded clinical mastitis data from 77,791 cows in 418 herds were used to determine the potential for genetic improvement of mastitis resistance using data from on-farm management software programs. The following threshold sire models were applied: 1) a single-trait lactation model, where mastitis was recorded as 0 or 1 in first lactation only; 2) a 3-trait lactation model, where mastitis was recorded as 0 or 1 in each of the first 3 lactations, and 3) a 12-trait, lactation-segment model, where mastitis was recorded as 0 or 1 in each of 4 segments (0 to 50, 51 to 155, 156 to 260, and 261 to 365 d postpartum) in each of the first 3 lactations. Lactation incidence rates were 0.16, 0.20, and 0.24 in first, second, and third lactation, respectively, and incidence rates within various segments of these lactations ranged from 0.036 in late first lactation to 0.093 in early third lactation. Estimated heritability of liability to clinical mastitis ranged from 0.07 to 0.15, depending on the model and stage of lactation. Heritability estimates were higher in first lactation than in subsequent lactations, but estimates were generally similar for different segments of the same lactation. Genetic correlations between lactations from the 3-trait model ranged from 0.42 to 0.49, while correlations between segments within lactation from the 12-trait model ranged from 0.26 to 0.64. Based on the results presented herein, it appears that at least 2 segments are needed per lactation, because mastitis in early lactation is lowly correlated with mastitis in mid or late lactation. Predicted transmitting abilities of sires ranged from 0.77 to 0.89 for probability of no mastitis during the first lactation and from 0.36 to 0.59 for probability of no mastitis during the first 3 lactations. Overall, this study shows that farmer-recorded clinical mastitis data can make a valuable contribution to genetic selection programs, but additional systems for gathering and storing this information must be developed, and more extensive data recording in progeny test herds should be encouraged.
(10-March-2006)
 

Chang, Y. M., Andersen-Ranberg, I. M., Heringstad, B., Gianola, D. Klemetsdal, G. 2006. "Bivariate Analysis of Number of Services to Conception and Days Open in Norwegian Red Using a Censored Threshold-Linear Model". Journal of Dairy Science, 89: 772-778.

KEYWORDS: Bivariate censored threshold-linear model, services to conception, days open, heritability

SUMMARY: A bivariate censored threshold-linear model was used to study genetic parameters of number of services to conception (STC) and days open (DO) in first-lactation Norwegian Red (NRF) cows. Records of 1,454,916 NRF cows, with a first insemination from 1980 to 2004, were analyzed. It was assumed that every cow had at least a first insemination. The number of inseminations was recorded until a cow conceived or was culled, whichever occurred first. If a cow was culled before conception, it was considered censored at the number of services until culling was recorded. Twenty-one percent of cows were censored for both STC and DO. Using an univariate probit link function for STC, unobserved liabilities to STC and DO were modeled jointly as a linear function of age at first calving, month-year at first calving, herd-5-yr period, sire of cow and residual effects. Heritability of liability to STC and DO was 4% for each trait. The genetic and residual correlations between STC and DO were 0.77 and 0.68, respectively. There has been little or no genetic change for DO, whereas STC had favorable genetic and phenotypic trends.
(10-March-2006)
 

Norberg, E., Rogers, G. W., Ødegård, J., Cooper, J. B., Madsen, P. 2006. "Short Communication: Genetic Correlation Between Test-Day Electrical Conductivity of Milk and Mastitis". Journal of Dairy Science, 89: 779-781.

KEYWORDS: Dairy cattle, mastitis, electrical conductivity, genetic correlation

SUMMARY: Electrical conductivity (EC) of milk is an indicator of mastitis. If EC shows genetic variation and is genetically correlated to mastitis, it could be used in a breeding program that includes selection for improved mastitis resistance. In this study, daily records of EC and mastitis from about 1,500 Holstein cows were analyzed. A bivariate animal model was used for estimation of (co)variance components, including fixed effects of age of calving, herd-test-day, and days in milk, in addition to random additive genetic effects and permanent environmental effects. For EC, the estimated heritability was moderate (0.22 to 0.39), whereas for mastitis, the heritability was low (0.013). The genetic correlation between EC and mastitis was estimated to be 0.75, and genetic improvement of mastitis resistance should be feasible through selection for reduced EC.
(10-March-2006)
 

Chen, H. Y., Zhang, Q., Yin, C. C., Wang, C. K., Gong, W. J., Mei, G. 2006. "Detection of Quantitative Trait Loci Affecting Milk Production Traits on Bovine Chromosome 6 in a Chinese Holstein Population by the Daughter Design". Journal of Dairy Science, 89: 782-790

KEYWORDS: Milk production trait, QTL mapping, Bos taurus autosome 6, daughter design

SUMMARY: Fourteen microsatellite markers with a coverage of 63.5 cM on bovine chromosome 6 were selected, and 26 sire families with 2,260 daughters were analyzed for mapping quantitative trait loci (QTL) affecting 5 milk production traits in a Chinese Holstein population. In the analyses across 26 families and within the largest significant families with a one-QTL model fitted, a QTL near BMS470 was detected that affected fat yield at the 5% experiment-wide significance level. When a 2-QTL model was fitted in the across-family analysis, it was found that there might exist 2 QTL affecting the 3 yield traits, although the exact or empirical thresholds for the significance testing were unknown. In all analyses, the results for milk yield and protein yield were generally consistent, which might have resulted from the same genetic background for milk and protein yield.
(10-March-2006)
 

Karacaören, B., Jaffrézic, F., Kadarmideen, H. N. 2006. "Genetic Parameters for Functional Traits in Dairy Cattle from Daily Random Regression Models". Journal of Dairy Science, 89: 791-798

KEYWORDS: Functional trait, production trait, genetic parameter, daily random regression model

SUMMARY: The objective of the research was to estimate genetic parameters, such as heritabilities and genetic correlations, using daily test day data for milk yield (MY), milking speed (MS), dry matter intake (DMI), and body weight (BW) using random regression methodology. Data were from first lactation dairy cows (n = 320) from the Chamau research farm of the Swiss Federal Institute of Technology, Switzerland over the period from April 1994 to 2004. All traits were recorded daily using automated machines. Estimated heritabilities (h2) varied from 0.18 to 0.30 (mean h2 = 0.24) for MY, 0.003 to 0.098 (mean h2 = 0.03) for MS, 0.22 to 0.53 (mean h2 = 0.43) for BW, and 0.12 to 0.34 (mean h2 = 0.23) for DMI. A permanent environmental effect was included in both the univariate and bivariate models, but was assumed constant in estimating some genetic correlations because of convergence problems. Estimated genetic correlations varied from 0.31 to 0.41 between MY and MS, from –0.47 to 0.29 between MY and DMI, from –0.60 to 0.54 between MY and BW, from 0.17 to 0.26 between MS and DMI, from –0.18 to 0.25 between MS and BW, and from –0.89 to 0.29 between DMI and BW. Genetic correlations for MY, MS, DMI, and BW from calving to midlactation decreased similarly to 0.40, 0.36, 0.14, and 0.36 and, at the end of the lactation, decreased to –0.06, 0.23, –0.07, and 0.09, respectively. Daily genetic variance-covariance of many functional traits are reported for the first time and will be useful when constructing selection indexes for more than one trait based on longitudinal genetic parameters.
(10-March-2006)
 

Krebs, S., Medugorac, I., Russ, I., Ossent, P., Bleul, U., Schmahl, W., Förster, M. 2006. "Fine-mapping and candidate gene analysis of bovine spinal muscular atrophy". Mammalian Genome, 17 (1): 67-76.

KEYWORDS: Fine-mapping, bovine spinal muscular atrophy

SUMMARY: Bovine spinal muscular atrophy (SMA), an autosomal recessive neurodegenerative disease, has been mapped at moderate resolution to the distal part of Chromosome 24. In this article we confirm this location and fine-map the SMA locus to an interval of approximately 0.8 cM at the very distal end of BTA24. Despite remarkable similarity to human SMA, the causative gene SMN can be excluded in bovine SMA. However, the interval where the disease now has been mapped contains BCL2, like SMN an antiapoptotic factor, and shown to bind to SMN. Moreover, knockout mice lacking the BCL2 gene show rapid motor neuron degeneration with early postnatal onset, as observed in bovine SMA. A comparative cattle/human map of the distal end of BTA24, based on the emerging bovine genome sequencing data, shows conserved synteny to HSA18 with hints of a segmental duplication and pericentic inversion just after the last available bovine marker DIK4971. This synteny lets us conclude that SMA is in immediate vicinity of the telomere. Candidate gene analysis of BCL2, however, excludes most of this gene, except its promoter region, and draws attention to the neighboring gene VPS4B, part of the endosomal protein-sorting machinery ESCRT-III which is involved in several neurodegenerative diseases.
(10-March-2006)
 

Adamowicz, T., Flisikowski, K., Starzyński, R., Zwierzchowski, L., Świtoński, M. 2006. "Mutation in the Sp1 motif of the bovine leptin gene affects its expression". Mammalian Genome, 17 (1): 77 – 82.

KEYWORDS: Mutation, Sp1 motif, bovine leptin gene, cattle.

SUMMARY: Leptin is expressed mainly by adipocytes and plays a crucial role in the regulation of energy expenditure, food intake, and adiposity. Using PCR-heteroduplex analysis and sequencing, A C/G substitution in the promoter region of the bovine leptin gene was investigated. Application of the electrophoretic mobility shift assay showed that the C→G transversion decreased the leptin gene promoter binding capacity for nuclear proteins. With real-time PCR and Western blotting, It was shown that the leptin expression level was higher in cattle with the CC than with the GG genotype.
(10-March-2006)
 

Roux, M., Nizou, A., Forestier, L., Ouali, A., Levéziel, H., Amarger, V. 2006. "Characterization of the bovine PRKAG3 gene: structure, polymorphism, and alternative transcripts". Mammalian Genome, 17 (1): 83-92

KEYWORDS: bovine PRKAG3 gene, polymorphism

SUMMARY: The bovine PRKAG3 gene encodes the AMPK γ3 subunit, one isoform of the regulatory γ subunit of the AMP-activated protein kinase (AMPK). The AMPK plays a major role in the regulation of energy metabolism and mutations affecting the genes encoding the γ subunits have been shown to influence AMPK activity. The γ3 subunit is involved in the regulation of AMPK activity in skeletal muscle and strongly inflences glycogen metabolism. Glycogen content in muscle is correlated to meat quality in livestock because it influences postmortem maturation process and ultimate pH. Naturally occurring mutations in the porcine PRKAG3 gene highly affect meat quality by influencing glycogen content before slaughter. We present the characterization of the bovine PRKAG3 gene and a polymorphism analysis in three cattle breeds. Thirty-two SNPs were identified among which 13 are in the coding region, one is in the 3′ UTR, and 18 are in the introns. Five of them change an amino acid in the PRKAG3 protein sequence. Allelic frequencies were determined in the three breeds considered, and mutant alleles affecting the coding sequence are found at a very low frequency. Alternative splicing sites were identified at two positions of the gene, introducing heterogeneity in the population of proteins translated from the gene.
(10-March-2006)
 

Gutiérrez, J.P., Fernández, I., Alvarez, I., Royo, L.J., Goyache, F. 2006. "Sire × contemporary group interactions for birth weight and preweaning growth traits in the Asturiana de los Valles beef cattle breed". Livestock Science, 99 (1): 60-68.

KEYWORDS: Preferential treatment; Heritability; Maternal effect; Genetic correlation; Birth weight; Weaning weight; Average daily gain.

SUMMARY: Although a number of recent studies have focused on the existence of a non-negligible sire × contemporary group interaction effect (s) affecting the estimation of genetic parameters for maternally influenced traits in beef cattle, the assessment and interpretation of this effect using field data remains poorly understood. In this study 27,639 records of both birth weight (BW) and weaning weight (WW) from the Asturiana de los Valles breed were used to assess the consequences of the inclusion of an s effect on the estimation of genetic parameters for BW, WW and average daily gain (ADG) fitting univariate and bivariate models. Estimations of s2 for BW, WW and ADG were 0.040, 0.070 and 0.077 regardless of the fitted model. Inclusion of s in the estimation models induced a reduction of both the direct and the maternal heritability, varying between 8 and 28% with the trait and the estimation model employed. The correlations between both direct and maternal genetic effects for each trait were less negative when s was included in the estimation model. The estimated correlations between the s effect affecting BW, WW and ADG were 0.108, − 0.038 and 0.616 for the pairs BW–WW, BW–ADG and WW–ADG, respectively. These results suggest that misidentification of individuals cannot be the sole cause of the effect of s and that this effect is of a different nature and origin for different traits (i.e. selective matings for low BW's and unaccounted management practices for preweaning growth traits). Models including the s effect should be accepted as working models in beef improvement schemes.
(10-March-2006)
 

Silva, J.A. II V., Formigoni, I.B., Eler, J.P., Ferraz, J.B.S. 2006. "Genetic relationship among stayability, scrotal circumference and post-weaning weight in Nelore cattle". Livestock Science, 99 (1): 51-59.

KEYWORDS: Beef cattle; Genetic correlation; Growth trait; Reproductive trait

SUMMARY: Improvement of female fertility has become of fundamental importance for profit maximization in the beef cattle herds. Consequently, animal breeding programs in Brazil have applied selection effort to traits related to reproduction as for scrotal circumference (SC), which is already incorporated to the selection routine of the breeders. However, studies have reported no favorable genetic correlation (rg) of SC with some fertility traits. Recently, stayability (STAY) has been used as means to better indicate and improve female fertility. Values for rg of STAY with reproductive and productive traits are not available in literature. Therefore, the objectives of the present study are to analyze the rg between SC and STAY and STAY with weight at 550 days (W550) in Nelore cattle. Data set of 55,682, 28,507 and 59,750 animals for STAY, SC and W550, respectively, were analyzed using two-trait animal model based on Gibbs sampling algorithm. The estimate of posterior rg between STAY and SC was 0.07 ± 0.03, which can be considered as low and suggesting that STAY does not have sensible relation with SC. The rg of STAY and W550 was 0.15 ± 0.01, considered low, although positive. It means that selection for W550 should not negatively affect STAY. (10-March-2006)
 

Smaragdov, M. G. 2006. "Genetic Mapping of Loci Responsible for Milk Production Traits in Dairy Cattle". Russian Journal of Genetics, 42 (1): 1-15.

KEYWORDS: Genetic Mapping, Milk Production Traits, Dairy Cattle

SUMMARY: The review presents a definition of loci controlling quantitative traits (quantitative trait loci, QTLs) and localization of all currently known QTLs responsible for milk production traits in dairy cattle. The QTL number and chromosome localization are verified, with special reference to chromosomes 1, 3, 6, 14, 20, and 23. In a number of cases, close location of QTLs for mastitis and for milk production traits was found. Some aspects of QTL pleiotropy and epistasis are discussed and mapping methods of major QTLs are listed.
(10-March-2006)

Oprzadek, J., Flisikowski, K., Zwierzchowski, L., Juszxzuk-Kubuak, E., Rosochacki, S., Dymnicki, E. 2005. "Associations between polymorphism of some candidate genes and growth rates, feed intake and utilisation, slaughter indicators and meet quality in cattle". Archiv Fűr Tierzucht, 48 (special issue): 81-87.

KEYWORDS: Leucine/valine substitution, bovine growth hormone, feed intake, carcass traits, cattle.

SUMMARY: This study shows that leucine/valine substitution at amino acid position 127 of the bovine growth hormone (GH) affects growth rate, feed intake/feed conversion as well as carcass traits in dairy and beef cattle. This indicates the GH gene as a potential locus of quantitative traits (QTL) in cattle. Moreover, associations were studied between the polymorphism at GH receptor (GHR), leptin (LEP), STAT5A, and PIT-1 loci and traits related to meat production in the growing Polish Friesian and beef bulls. Statistically significant differences were found between various genotypes at the loci studied and feed consumption, meat production, and carcass quality traits. Analysis of beef bulls revealed differences in meat quality between calpain (CAPN1) genotypes, the animals of the GC genotype had highest cooking loss and darker color of meat, a difference was also observed between genotypes in the total content of hem pigment of meat.
(26-Jan-2006)
 

Lazarevic, R., Miscevic, B. 2005. "Inheritance of some fertility traits in three successive generations of Holstein-Friesian cattle". Archiv Fűr Tierzucht, 48: 5-11.

KEYWORDS: Fertility, Friesian, heritability, duration of pregnancy, service period

SUMMARY The aim of the paper was to establish reproductive traits and their heritability during the three successive generations of Holstein-Friesian cattle. Research was conducted on the duration of pregnancy, service period and fertility intensity. In each generation there were 135 first calved cows. Service period and fertility intensity refers to the following calving. Significant differences were established (P<0.05) regarding duration of pregnancy between I and II generation. Significant (P<0.05) influence of season on duration of pregnancy and service period was established in I generation (1991), on duration of service period and fertility intensity in II generation (1996) and on duration of pregnancy and service period in III generation (2000). Season effect (summer) was established for all traits of fertility in II generation (P<0.05). The season (spring) had influence on duration of pregnancy (P<0.05) and summer had an influence on duration of service period and fertility intensity, and winter effected the duration of service period (P<0.05) in III generation. Values of heritability coefficients are pretty low for all generations. Considerably greater values for heritability were established for service period and intensity of fertility of cows per generations.
(26-Jan-2006)
 

Freyer, G., Hernández-Sánchez, J., Cassell, B.G. 2005. "A note on inbreeding in dairy cattle breeding". Archiv Fűr Tierzucht, 48: 130-137.

KEYWORDS: Inbreeding, dairy cattle

SUMMARY: Several research groups worldwide presented effective tools for managing inbreeding in dairy cattle. Their efforts underline the need of inbreeding studies. Contemplating inbreeding is necessary for any breeding decision to avoid inbreeding depression and for improved genetic analyses, e.g. in QTL- estimation. A novel methodology is suggested for estimating inbreeding at the three levels of population, individual and locus.
(26-Jan-2006)
 

Dybus, A., Grzeslak, W., Kamieniecki, H., Szatkowska, I., Sobek, Z., Blaszczyk, P., Czerniawska-Piatkowska, E., Zych, S., Muszynska, M. 2005. "Association of genetic variants of bovine prolactin with milk production traits of Black-and-White and Jersey cattle". Archiv Fűr Tierzucht, 48: 149-156.

KEYWORDS: Prolactin gene, milk production, Jersey, PCR-RFLP, gene frequency

SUMMARY: Associations between polymorphism localised in the third exon of the prolactin gene (PRL-RsaI) and milk production traits of Black-and-White and Jersey cattle were analysed. A total of 427 cows were included in the study. PCR-RFLP method was used. The frequencies of genotypes and alleles were as follows: 0.7107 - AA, 0.2851 - AB, 0.0042 - BB, 0.8533 - PRLA and 0.1467 - PRLB for Black-and-White cattle and 0.0919 - AA, 0.4324 - AB, 0.4757 - BB, 0.3081 - PRLA and 0.6919 - PRLB for Jersey cattle. Statistically significant differences between the breeds were observed in the frequencies of genotypes and alleles. Associations between PRL-RsaI polymorphism and milk production traits of Jersey cows and lack of associations with these traits in Black-and-White cows were observed.
(26-Jan-2006)
 

Distl, O. 2005. "The use of molecular genetics in eliminating of inherited anomalies in cattle". Archiv Fűr Tierzucht, 48: 209-218.

KEYWORDS: Molecular genetics, inherited defects, cattle

SUMMARY: Genetic improvement programmes in cattle have significantly contributed to the large increase in milk and meat production. As along with these breeding schemes top ranking AI sires are widely used and in the case, if these sires are carriers of mutated alleles, inherited defects can be widely disseminated. Most of the about 350 inherited anomalies in cattle occur at very low to low frequencies and thus, carriers are usually not detected in progeny tests based on reporting calves with congenital malformations. The molecular genetic decipherment of inherited anomalies is the necessary prerequisite for an efficient prevention of the dissemination of undesired alleles. The paper gives a survey on inherited anomalies being already characterized in cattle with molecular genetic methods. Furthermore, two genetic anomalies, namely congenital X-linked ectodermal dysplasia with hypotrichosis and missing teeth and bilateral convergent strabismus with exophthalmus are described in more detail.
(26-Jan-2006)
 

Harder, B., Bennewitz, J., Reinsch, N., Mayer, M., Kalm, E. 2005. "Effect of missing sire information on genetic evaluation". Archiv Fűr Tierzucht, 48: 219-232

KEYWORDS: Missing sire information, genetic evaluation, Stochastic simulation

SUMMARY: Stochastic simulation was used to analyse the effect of missing sire information (MSI) on different parameters of genetic evaluation. Eighty proven bulls producing 100 progeny and 40 test bulls producing 50 progeny were simulated. The proportion of MSI was varied in four steps from 10 to 40%. Analyses were carried out for h² = 0.10 and h² = 0.25. A sire model was used for simulation and evaluation. The variance of DYD increased with increasing proportion of MSI. Variances of sire breeding values as well as rank correlations decreased with increasing proportion of MSI. The probability that the simulated Top 5 and Top 10 bulls were placed under the estimated Top 5 and Top 10 bulls, respectively, decreased with increasing percentage of MSI. The same holds true for the probability of ranking a bull with 10 to 40% MSI under the 5% best bulls with complete pedigree. The loss of response to selection increased up to 8.6% for proven bulls and up to 12.6% for test bulls.
(26-Jan-2006)
 

König, S., Chongkasikit,, N., Langholz, H.-J. 2005. "Estimation of variance components for production and fertility traits in Northern Thai dairy cattle to define optimal breeding strategies". Archiv Fűr Tierzucht, 48: 233-246.

KEYWORDS: Milk production, Thailand, dairy cattle, fertility

SUMMARY: Milk production in Thailand has been growing into an important agricultural sector, but it still faces numerous difficulties in environmental constraints. The main intention of this study was to identify significant environmental effects on production and fertility traits to give advices for farm management. Additionally, adjusting records for environmental impact is essential to define appropriate models for estimation of variance components and improving selection procedures. The data consists of production and reproduction records and body measurements from 2764 Holstein upgrade cows in 252 farms. With a body weight of 415 kg and a production level of 3668 kg milk, Thai Holsteins only reach approximately 60 % of performances of Holsteins in temperate zones. Percentages of Holstein genes of cows and quality of roughage sources showed a certain effect on calving interval and services per conception but not on milk performances. Despite seasonal effects were not very pronounced on milk yield, there was a strong interaction between years and calving seasons. Estimates of variance components applying REML and animal models were in the range as expected, i.e. heritabilities for production traits between 0.34 and 0.37, for fertility lower than 0.03 and for body weight 0.46. Genetic correlations between fertility and production traits were near zero. Economic weights for milk yield and calving interval were derived as first derivation of profit functions and used for selection index calculations. Success in fertility is possible if at least 130 daughters per bull are recorded and if fertility is a part of index sources.
(26-Jan-2006)
 

Schwerin, M., Goldammer, T., Kuehn, C.H., Walz, C.H., Ponsuksili, S. 2005. "Identification of genetic variants in differentially expressed sequences in cattle of different metabolic type–potential genetic markers of nutrient utilization". Archiv Fűr Tierzucht, 48: 324-333

KEYWORDS: Genetic variants, nutrient transformation, Holsteins, Charolais

SUMMARY: Two cattle breeds serve as a model to identify genes and genetic variants, respectively, that are potentially associated with nutrient transformation: Holsteins bred for high milk production mainly, and Charolais bred for high body weight with outstanding muscular growth. The major differences between Charolais and Holstein regarding many general body parameters originate from differences in pathways and deposition of nutrients. In an initial experiment, expressed sequence tags (ESTs) differentially displayed between both cattle breeds were isolated by mRNA differential display in liver and intestine. Of the total identified 277 ESTs, 79 showing the most prominent differences, were screened for single nucleotide polymorphisms (SNPs). Thirty four SNPs were detected in 30 ESTs in a direct sequencing approach based on the comparative sequencing of the corresponding amplicons generated by PCR from genomic DNA pools of 20 animals each of both cattle breeds,. Eighteen of these SNPs showed breed specific distribution of allelic variants. Occurrence of ESTs with a breed specific SNP distribution and localisation of the respective ESTs to chromosome regions known to be affecting carcass and growth traits in cattle suggest a trait association of the respective SNPs. The polymorphic nature of the SNP markers suggests that they will be useful for evaluating whether variation in these genomic regions influences nutrient pathways in cattle.
(26-Jan-2006)
 

Debeljak, M., Frajman, P., Lenasi, T., Narat, M., Baldi, A., Dovc, P. 2005. "Functional analysis of the bovine beta- and kappa casein gene promoters using homologous mammary gland derived cell line". Archiv Fűr Tierzucht, 48: 334-345

KEYWORDS: Bovine casein, marker assisted selection, dairy cattle

SUMMARY: Bovine casein gene cluster belongs to the best studied regions of the bovine genome. However, molecular basis of the regulation of casein gene expression is still of great interest for the advancement of milk production. Identification of crucial regulatory regions governing casein gene expression would provide valuable information for marker assisted selection in dairy cattle. Comparative analysis of the bovine beta- and kappa casein gene promoter sequences with the regulatory sequences from some other species was performed. In addition, homologous mammary gland derived cell culture and luciferase reporter gene system were used to confirm the functionality of the proximal beta and kappa casein promoters. The longer kappa casein promoter (2064 bp) showed the highest expression level, followed by the short kappa casein promoter (925 bp) and beta casein promoter (1692 bp). The suitability of the bovine mammary gland derived cell line BME UV1 for transient gene expression under transcriptional control of the bovine casein gene promoters was demonstrated and functionality of different fragments of bovine beta- and kappa casein gene promoters using homologous in vitro system was compared..
(26-Jan-2006)
 

Kulig, H. 2005. "Association between leptin combined genotypes and milk performance traits of Polish Black-and-White cows". Archiv Fűr Tierzucht, 48: 547-554

KEYWORDS: Leptin, milk yield, fat content, Holstein-Friesian

SUMMARY: The aim of this study was to estimate the relations between the leptin combined genotypes versus milk performance traits (yields of milk, protein, and fat, as well as protein and fat content). The investigation was performed on 860 Black-and-White cows with a different share of the Holstein-Friesian genes, kept in Pomerania. Frequencies of the LEP-C3100T/Sau3AI genotypes were: CC/AA – 0. 315, CT/AA – 0.272 and CC/AB – 0.142. The frequencies of the remaining genotypes did not exceed 0.100. Statistically significant (P≤0.01) relation between the leptin combined genotypes (LEP-C3100T/Sau3AI) and milk, protein, and fat yield were observed. These traits were significantly higher in the CC/BB genotype cows.
(26-Jan-2006)
 

Meyer, K. 2005. "Genetic principal components for live ultrasound scan traits of Angus cattle". Animal Science, 81 (Part 3): 337-346

KEYWORDS: Beef cattle, genetic parameters, principal component analysis, reduced rank estimation.

SUMMARY: Multivariate restricted maximum likelihood analyses were carried out for a large data set comprising records for eye-muscle area, fat depth at the 12/13th rib and the rump P8 site, and percentage intramuscular fat, recorded via live ultrasound scanning of Australian Angus cattle. Records on heifers or steers were treated as separate traits from those on bulls. Reduced rank estimates of the genetic covariance matrix were obtained by restricted maximum likelihood, estimating the leading three, four, five, six, seven and all eight principal components and these were contrasted with estimates from pooled bivariate analyses. Results from analyses fitting five or six genetic principal components agreed closely with estimates from bivariate and eight-variate analyses and literature results. Heritabilities and variances for ‘fatness’ traits measured on heifers or steers were higher than those recorded for bulls, and genetic correlations were less than unity for the same trait measured in different sexes. Eye-muscle area showed little association with the other traits. Reduced rank estimation decreased computational requirements of multivariate analyses dramatically, in essence corresponding to those of an m-variate analysis for m principal components considered. Five or six principal components appeared to be necessary to model genetic covariances adequately. The first three of these components then explained about 97% of the genetic variation among the eight traits. A simulation study showed that errors in reduced rank estimates of the genetic covariance matrix were small, once three or more principal components from analyses fitting five or more components were used in constructing the estimates. Similarly, accuracy of genetic evaluation for the eight traits using the first four components was only slightly less than that using all principal components. Results suggest that reduced rank estimation and prediction is applicable for the eight scan traits considered. The leading three to four principal components sufficed to describe the bulk of genetic variation between animals. However, five or more principal components needed to be considered in estimating covariance matrices and the ‘loadings’ of the original traits to the principal components.
(26-Jan-2006)

Kunieda, T. 2005. "Identification of genes responsible for hereditary diseases in Japanese beef cattle". Animal Science Journal, 76 (6): 525-533

KEYWORDS: Breeding, DNA diagnosis, hereditary disease, Japanese beef cattle, mutation

SUMMARY: In the breeding of domestic animals, selection of economically desired traits has been the most important consideration for the improvement of animals, but excluding negative factors in animal production, such as causative genes for hereditary diseases, is also required for the genetic improvement of domestic animals. The incidence of various hereditary diseases has been reported in Japanese beef cattle and these diseases have caused serious problems in the breeding and raising of healthy beef cattle. This article reviews the identification of causative genes for the following three hereditary diseases in Japanese beef cattle: (i) Chediak–Higashi syndrome; (ii) renal tubular dysplasia; and (iii) bovine chondrodysplastic dwarfism. Chediak–Higashi syndrome is a hereditary bleeding disorder reported in Japanese black cattle. To identify the cause of this disease, the bovine LYST gene was cloned and sequenced. This gene has been found to be involved in Chediak–Higashi syndrome in humans, and found that an amino acid substitution of histidine to arginine at amino acid residue 2015 is the causative mutation in the cattle disease. Renal tubular dysplasia is a hereditary disease of Japanese black cattle showing renal failure and growth retardation. The locus for this disease was mapped to the 4 cM region of bovine chromosome 1 by linkage analysis and found a large deletion in this region. The deleted region contained the PCLN1 gene encoding a tight-junction protein of renal epithelial cells. It was concluded that deletion of the PCLN1 gene is responsible for the disease. Bovine chondrodysplastic dwarfism is a hereditary disease of Japanese brown cattle, displayed by short limbs and joint abnormalities. The locus for the disease to was mapped a region of bovine chromosome 6 by linkage analysis. By constructing YAC and BAC contigs covering this region and sequence analysis, a novel gene (LIMBIN), which plays an essential role in bone formation in this region was identified, and two mutations responsible for the disease were found. The identification of these mutations provided the basis for DNA-based diagnostic systems for these three diseases, and after development of the diagnosis systems, the incidences of these hereditary diseases have dramatically decreased.
(26-Jan-2006)
 

Komatsua, T., Itoh, F., Hodate, K., Hazegawa, S., Obara, Y.. Kushibiki, S. 2005. "Gene expression of resistin and TNF-α in adipose tissue of Japanese Black steers and Holstein steers". Animal Science Journal, 76 (6): 567-573.

KEYWORDS: Adipose tissue, Holstein steers, Japanese Black steers, resistin, tumor necrosis factor-α

SUMMARY: The aim of the present study was to compare the expression of adipose tissue mRNA related to glucose metabolism between Japanese Black steers (n = 5) and Holstein steers (n = 5). The expression of the resistin, tumor necrosis factor-α (TNF-α), glucose transporter 1 (GLUT1) and growth hormone receptor (GHR) genes were found using real-time polymerase chain reaction of cDNA in adipose tissue. The cDNA sequence identified by 5'/3'-rapid amplification of cDNA and the deduced amino acid sequence were highly conserved in human, porcine and murine resistin. Expression of resistin mRNA was significantly greater in Holstein steers than in Japanese Black steers. In contrast, expression of TNF-α mRNA was slightly greater in Japanese Black steers. Expression of GHR mRNA was significantly greater in Japanese Black steers compared with the Holstein steers, although there was no significant difference in the expression of GLUT1 mRNA. However, the plasma non-esterified fatty acid (NEFA), glucose, insulin and growth hormone concentrations did not differ between Japanese Black and Holstein steers. The present results show that there is a difference in the expression level of mRNA related to glucose metabolism between Japanese Black steers and Holstein steers.
(26-Jan-2006)
 

Chirinos, Z., Hernández, D., Carabaño, M. 2005 "Effect of somatic cell scores on functional longevity of dairy cattle assessed by survival analysis". Archivos Latinoamericanos de Producción Animal, available at: http://www.alpa.org.ve/ojs/viewarticle.php?id=256.

KEYWORDS: Somatic cell score, longevity, dairy cattle.

SUMMARY: The objective of this study was to analyze the effect of somatic cell scores on functional longevity (FL) assessed using survival analysis. Longevity was measured as days of productive life. FL was obtained by longevity global correcting for milk production. Data of production and somatic cell count (SCC) were used (n=20.359), with date of first calving between 1988 and 2000. The weibull model studied factors: herd-year-season of calving (HYS), age at first calving (AFC), lactation number-stage of lactation (NS), annual change in herd size (CHZ), milk (MY), fat (FY) and protein (PY) yield. All the effects were significant (P< 0.001) and contributed to explain the differences on the relative risk of culling (RR). An increase in the SCC levels caused a greater RR. An important effect of SCC and udder depth in FL was observed. Cows with greater SCC had almost 4.0 times more RR and it was more evident in very deep udders animals.
(26-Jan-2006)
 

Teixeira, R.A., Albuquerque, L.G. 2005. "Maternal and individual heterosis for preweaning daily gain in Nellore × Hereford and Nellore × Angus cattle". Arquivo Brasileiro de Medicina Veterinária e Zootecnia, 57: 518-523.

KEYWORDS: Beef cattle; crossbreeding; additive effect; non-additive effect

SUMMARY: Data on 62.985 Nellore, Hereford, Angus and Nellore × Angus and Nellore × Hereford crossbred calves were analyzed to estimate maternal and individual heterosis for preweaning daily weight gain (PWD). The individual and maternal heterosis of average daily weight gain showed improvements of 6.2 and 11.2% for PWD of F1 calves and for calves borne from F1 dams. Maternal heterosis corresponded to 64.5% of total heterosis. Bos taurus × Bos indicus crossbred cattle have a PWD larger than the average of purebred cattle.
(26-Jan-2006)
 

Gressler, M.G.M., Pereira, J.C.C., Bergmann, J.A.G. 2005. "Genetic aspects of weaning weight and some reproductive traits in Nellore cattle:. Arquivo Brasileiro de Medicina Veterinária e Zootecnia, 57: 533-538.

KEYWORDS: Cattle; genetic correlation; heritability, weaning weight

SUMMARY: Estimates of genetic parameters for weaning weight adjusted to 240 days of age (WW240), age at first calving (AFC), age at second calving (ASC) and first calving interval (FCI) in Nellore cattle using REML methodology (MTDFREML), were obtained. Heritability estimates from univariate analyses were: 0.48±0.20; 0.27±0.15; 0.14±0.16; and 0.03±0.13, for WW240, AFC, ASC and FCI, respectively. Genetic correlation estimates between AFC and ASC and AFC and FCI were 0.97, -0.92, respectively. The genetic correlation between ASC and FCI was -0.82. The genetic correlations between WW240 and AFC, ASC and FCI were -0.20, 0.00 and 1.00, respectively.
(26-Jan-2006)
 

Sapp, R.L., Spangler, M.L., Rekaya, R., Bertrand, J.K. 2005. "A simulation study for the analysis of uncertain binary responses: Application to first insemination success in beef cattle". Genetic Selection Evolution, 37: 615-634

KEYWORDS: Binary data, fertility, fuzzy logic, simulation, threshold model

SUMMARY: A simulation was carried out to investigate the methods of analyzing uncertain binary responses for success or failure at first insemination. A linear mixed model that included, herd, year, and month of mating as fixed effects; and unrelated service sire, sire and residual as random effects was used to generate binary data. Binary responses were assigned using the difference between days to calving and average gestation length. Females deviating from average gestation length lead to uncertain binary responses. Thus, the methods investigated were the following: (1) a threshold model fitted to certain (no uncertainty) binary data (M1); (2) a threshold model fitted to uncertain binary data ignoring uncertainty (M2); and (3) analysis of uncertain binary data, accounting for uncertainty from day 16 to 26 (M3) or from day 14 to 28 (M4) after introduction of the bull, using a threshold model with fuzzy logic classification. There was virtually no difference between point estimates obtained from M1, M3, and M4 with true values. When uncertain binary data were analyzed ignoring uncertainty (M2), sire variance and heritability were underestimated by 22 and 24%, respectively. Thus, for noisy binary data, a threshold model contemplating uncertainty is needed to avoid bias when estimating genetic parameters.
(26-Jan-2006)
 

Robbins, K. R., Misztal, I., Bertrand, J. K. 2005. "Joint longitudinal modeling of age of dam and age of animal for growth traits in beef cattle". Journal of Animal Science, 83:: 2736-2742

KEYWORDS: Cross Validation, Polynomial Regression, Two-Dimensional Spline

SUMMARY: Two methods to jointly model age of dam (AOD) and age of animal in random regression analyses of growth in Gelbvieh cattle were examined. The first method (M1) was analogous to the multiple-trait analysis and consisted of AOD as a nested class variable and a cubic polynomial regression on age nested within birth, weaning, and yearly weights. The second method (M2) used two-dimensional splines, with age knots at 150, 205, 270, 340, and 390 d. The AOD knots were placed at 725, 1,464, and 2,189 d. These selected knots were used to form a two-dimensional grid containing 15 knots, each representing a specific age and AOD combination. A data set containing Gelbvieh growth records was split along contemporary groups into two data sets. Data set 1 contained 316,078 records and was used for prediction by mixed-model equations. Data set 2 contained 164,167 records and was used for cross validation. In the complete data set, only 90 and 30% of animals with birth weight had records on weaning and yearling weights, respectively. Models were evaluated based on R2, average squared error (ASE), percent bias, and plots of solutions. The ASE for weights associated with birth weight, weaning weight, and yearling weight for M1 were 15, 505, and 703 kg2. With M2, large jumps in fixed-effect estimates were observed outside the two-dimensional grid. To eliminate this problem, weighted one-dimensional splines were used for extrapolation beyond the two-dimensional grid. For M2 with weighted spline extrapolation, the ASE were 15, 542, and 777 kg2 for birth weight, weaning weight, and yearling weight, respectively. Creation of optimal two-dimensional splines is difficult when data are clustered. Despite such difficulties, the two-dimensional spline was capable of jointly and continuously modeling AOD and age of animal.
(26-Jan-2006)
 

Mitchell, R. G., Rogers, G. W., Dechow, C. D., Vallimont, J. E., Cooper, J. B., Sander-Nielsen, U., Clay, J. S. 2005. "Milk Urea Nitrogen Concentration: Heritability and Genetic Correlations with Reproductive Performance and Disease". Journal of Dairy Science, 88: 4434-4440.

KEYWORDS: milk urea nitrogen, reproductive performance, disease, genetic correlation

SUMMARY: The objectives of this study were to estimate the heritability of milk urea nitrogen (MUN) concentration and describe the genetic relationship between MUN and reproductive performance and between MUN and diseases in Holsteins. Dairy Records Management Systems (Raleigh, NC) provided lactation data. The Danish Agricultural Advisory Center provided breeding value estimates for diseases. Infrared (IR) and wet chemistry (WC) data were analyzed separately. Heritabilities and genetic correlations for 2 different measures of MUN and reproductive performance were estimated with an animal model using ASREML. Heritabilities for MUN were estimated using all lactations combined (lactations 1 through 5) and separately for first lactation and second lactation. Genetic correlations with reproduction and health were estimated separately for parities 1 and 2. Herd-test-day or herd-year-season along with age at calving and days in milk were included as fixed effects in all models. Heritability estimates for all lactations combined were 0.15 for WC MUN and 0.22 for IR MUN. Genetic correlations between WC MUN and 2 measures of reproductive performance, days to first service, and first service conception were not different from zero. In contrast, the genetic correlation between WC MUN and days open of 0.21 in first lactation and 0.41 in second lactation indicated that higher WC MUN values were associated with increased days open. Correlations among estimated breeding values for MUN and estimated breeding values for Danish diseases identified no significant relationships. Although the results of this study indicate that heritable variation for MUN exists, the inability to identify significant genetic relationships with several measures of disease or reproductive performance appears to limit the value of MUN in selection for disease resistance and improved reproduction.
(26-Jan-2006)
 

Kearney, J. F., Amer, P. R., Villanueva, B. 2005. "Cumulative Discounted Expressions of Sire Genotypes for the Complex Vertebral Malformation and ß-Casein Loci in Commercial Dairy Herds". Journal of Dairy Science, 88: 4426-4433

KEYWORDS: gene-flow, genotype, cumulative discounted expression, commercial dairy herd

SUMMARY: Based on discounted gene-flow principles, a set of recursive equations was developed to quantify the value of using sires with a specific genotype for an identified gene in a commercial dairy herd. Two examples were used to demonstrate the usefulness of the method. The first example deals with the implications of using sires that are known carriers of the lethal recessive genetic defect, complex vertebral malformation (CVM). The second example examines the value of using sires homozygous for the A2 allele of ß-casein. Results are presented in terms of cumulative discounted expressions. These are then multiplied by the economic values of specific genotypes to determine the cost or benefit of using these sires. In general, the degree of mortality and the required price reduction for carrier sires increased as the proportion of carrier sires used, the duration of sire use, and the initial frequency in the cow herd increased. A semen discount of £3.10 per CVM straw used would be required to offset the expected mortality when 20% of CVM carrier sires are used for 3 yr when 5% of cows are carriers. The cumulative discounted expressions’ of using sires homozygous for the A2 allele of ß-casein also increased when the proportion and duration of carrier sire use and the initial frequency of the A2 allele increased. Assuming an A2A2 cow is worth £160 more than a non-A2A2 cow, the expected benefit of using A2A2 sires in a 100-cow herd for 5 yr would be £57,120 for a 20-yr planning horizon. The results of this study demonstrate how the starting gene frequency in the herd, and the proportion and duration of use of sires of particular genotypes are critical to the economic implications of using single genes in commercial dairy farms.
(26-Jan-2006)
 

Ashwell, M. S., Heyen, D. W., Weller, J. I., Ron, M., Sonstegard, T. S., Van Tassell, C. P., Lewin, H. A. 2005. "Detection of Quantitative Trait Loci Influencing Conformation Traits and Calving Ease in Holstein-Friesian Cattle". Journal of Dairy Science, 88: 4111-4119.

KEYWORDS: genome scan, dairy, conformation, quantitative trait loci

SUMMARY: An extension of previous genome scan of a North American Holstein-Friesian population was conducted to identify quantitative trait loci (QTL) affecting conformation traits. Resource families consisted of 1404 sons of 10 elite sires. Genome coverage was estimated to be 2713.5 cM (90%) for 406 markers using a granddaughter design. Regression interval mapping was used to detect QTL affecting 22 conformation traits, including body, udder, feet and legs, and dairy conformation as well as calving ease. Analysis of the families jointly identified 41 chromosome-wise significant QTL influencing conformation traits and 3 significant QTL influencing calving ease on 20 chromosomes. The false discovery rate method was used to account for multiple testing and 3/4 of the suggestive and 5/6 of significant QTL should be real effects. Fourteen of the 44 QTL were significant at the genome-wise level. Comparison of these results with other published reports identifies common QTL affecting conformation traits. Regions on 10 chromosomes appear to affect multiple traits, including conformation, milk production, and somatic cell score, within these particular US Holstein families. Additional work is needed to determine the precise locations of the QTL and select positional candidate genes influencing these traits.
(26-Jan-2006)
 

Yonai, M., Kaneyama, K., Miyashita, N., Kobayashi, S., Goto, Y., Bettpu, T., Nagai, T. 2005. "Growth, Reproduction, and Lactation in Somatic Cell Cloned Cows with Short Telomeres". Journal of Dairy Science, 88: 4097-4110

KEYWORDS: productivity, cloned cows, short telomeres

SUMMARY: It was previously shown that telomere lengths of 10 somatic cell cloned cows were significantly shorter than normal. In this study, growth, reproduction, and lactation in these animals were studied to determine if shortened telomeres have any effect on these characteristics. Six Holstein and 4 Jersey cloned cows, derived from oviduct cells, were reared under general group feeding. Body weights were recorded from birth to 48 mo of age. A number of reproductive characteristics were screened during the prepubertal, postpubertal, and postpartum periods. After parturition, milk yields were recorded daily and percentages of milk fat, proteins, and solids-not-fat were measured at monthly intervals. These data were used to estimate production of milk components over a 305-d period. Overall, the cloned heifers exceeded standard growth rates for each breed. The cows were inseminated at the first estrus after they reached 450 d of age, and delivered normal calves except for one stillbirth in the Holstein group. They were inseminated at postpartum estrus to provide second and third parturitions and, again, these pregnancies were normal. Gestational periods and birth weights of the calves were both within the normal range. The average total milk yield per cow in Holstein group clones was less than that of the original cow, whereas Jersey group clones showed a higher average milk yield than the original cow. In both groups of cloned cows, inter-individual variation in milk production was relatively large; however, the coefficient of variation was less than 10%. The results suggest that the cloned cows have normal growth, reproductive, and lactation characteristics, and thus normal productivity, despite having reduced telomere lengths.
(26-Jan-2006)
 

König, S., Dietl, G., Raeder, I., Swalve, H. H. 2005. "Genetic Relationships for Dairy Performance Between Large-Scale and Small-Scale Farm Conditions". Journal of Dairy Science, 88: 4087-4096

KEYWORDS: genotype x environment interaction, large-scale farm, small-scale farm, milk production

SUMMARY: Genotype by environment interaction can be detected via the estimation of genetic correlations between environments under an animal model based on data comprising genetic links between the strata. Genetic correlations were estimated for protein yield of Holstein cows within and across regions of Germany using REML under an animal model for lactation and test-day records. Subsets of the entire data were created, stratified by region or herd size within region, and comprised between 16,307 and 132,972 cows with first-lactation records. Substantial heterogeneity exists between regions in Western and Eastern Germany. In Western states, most farms are small, with typical herd sizes of 30 to 60 cows, whereas in Eastern states, mostly large herds with herd sizes of 500 to 2000 cows are common. The results show drastic differences for residual and permanent environmental variance components between Eastern and Western regions with increases of around 30% for Eastern regions. Additive genetic variances were of similar magnitude in both regions. Genetic correlations between Eastern and Western states were between 0.90 and 0.95 but dropped to 0.79 when data from an Eastern state were reduced to contain large herds only. The results indicate that differences in herd size account for more of the differences in genetic correlation than do geographic regional differences.
(26-Jan-2006)
 

Leonard, S., Khatib, H., Schutzkus, V., Chang, Y. M., Maltecca, C. 2005. "Effects of the Osteopontin Gene Variants on Milk Production Traits in Dairy Cattle". Journal of Dairy Science, 88: 4083-4086

KEYWORDS: osteopontin, quantitative trait loci, production trait

SUMMARY: Osteopontin (OPN) is a highly phosphorylated glycoprotein whose gene has been cloned and sequenced in different species. Several whole genome scans have identified quantitative trait loci (QTL) affecting milk production traits on bovine chromosome 6 close to the osteopontin gene (OPN) location. The presence of OPN in milk and its elevated expression in mammary gland epithelial cells together with previous QTL studies have prompted the interest in investigating the effects of OPN variants on milk production traits in the Holstein dairy cattle population. A single nucleotide polymorphism in intron 4 (C/T) was detected and primers were designed to amplify genomic DNA from 1362 bulls obtained from Cooperative Dairy DNA Repository and from 214 cows from the University of Wisconsin herd. For the Repository population, the C allele was associated with an increase in milk protein percentage and milk fat percentage. Correlation between milk protein percentage and milk fat percentage was about 0.57. For the University of Wisconsin herd, the estimates of the effects of allele C were in the same direction as for the Repository population, although these estimates did not reach statistical significance. The results of this study are consistent with other studies that showed a significant association of the microsatellite markers in the region of OPN with milk protein percentage and other correlated traits.
(26-Jan-2006)
 

Gebeyehu, G., Asmare, A., Asseged, B. 2005. "Reproductive performances of Fogera cattle and their Friesian crosses in Andassa ranch, Northwestern Ethiopia". Livestock Research for Rural Development. Volume 17, Article #131. Retrieved from: http://www.cipav.org.co/lrrd/lrrd17/12/gosh17131.htm

KEYWORDS: crossbred, Fogera, Friesian, parity, season

SUMMARY: A study was conducted in Andassa Cattle Breeding and Improvement Ranch (ACBIR), northwestern Ethiopia, with the aims of assessing the reproductive performance of Fogera cattle and their Friesian crosses. The study involved the use of data compiled on record books and individual animal cards, and monitoring. General Linear Model (GLM) was used to analyze the data. The overall mean age at first service (AFS), number of services per-conception (NSC) and days open (DO) were 40.6±8 months, 1.62±0.1 and 305±10 days respectively. AFS was significantly affected by breed group; NSC and DO were significantly affected by parity of the cows; whereas season of birth/calving does not seem to have a significant effect on any of the traits measured. Although wide variations were recorded among study (26-Jan-2006)
SUBJECTs, the performance of the breed (and the crosses) was low indicating that poor management prevails in the center. The wide ranges of values recorded, however, create an avenue to improve the performance of the breed or its crosses through rigorous selection procedures.
(26-Jan-2006)
 

Balbus, N., Humeny, A., Kashkevich, K., Henz, I., Fischer, C., Becker, C.-M., Schiebel, K. 2005. "DNA polymorphisms of the prion doppel gene region in four different German cattle breeds and cows tested positive for bovine spongiform encephalopathy". Mammalian Genome, 16: 884 – 892.

KEYWORDS: Prion doppel gene, Creutzfeldt-Jacob disease, polymorphisms, German cattle breeds.

SUMMARY: Polymorphisms of the prion protein gene PRNP have been shown to influence the susceptibility/resistance to prion infections in human and sheep. In addition, the T174M polymorphism within the flanking prion doppel gene (PRND) was thought to be involved in susceptibility to sporadic Creutzfeldt-Jacob disease. To study a possible influence of DNA polymorphisms of the bovine PRND gene in bovine spongiform encephalopathy (BSE), previously identified and newly isolated DNA polymorphisms were genotyped in all available German cattle that tested positive for BSE. Genotypes and calculated haplotypes were compared with breeding bulls serving as controls. Analysis of the four major breeds Schwarzbunt (Holstein Friesian), Rotbunt (Holstein Red), Fleckvieh (Simmental), and Braunvieh (Swiss Brown) resulted in the isolation of the previously known polymorphisms R50H and R132Q and two novel synonymous single nucleotide polymorphisms (SNPs) C4820T and A5063T. Comparative genotype and haplotype analysis of BSE and control animals revealed a significantly different distribution of polymorphisms C4815T and R132Q in Fleckvieh animals but not in the other breeds tested. No association to BSE susceptibility was detectable for polymorphisms R50H and A5063T.
(26-Jan-2006)
 

Miller, P.J., Finucane, K.A., Hughes, M., Zhao, F-Q. 2005. "Cloning and Expression of Bovine Glucose Transporter GLUT12". Mammalian Genome, 16: 873 – 883.

KEYWORDS: Cloning, GLUT12, milk synthesis,

SUMMARY: GLUT12 is a new member of facilitative glucose transporters. It was originally cloned from a human breast cancer cell line and its expression has been detected in rat mammary gland. Glucose transport across the plasma membrane of mammary epithelial cells is a rate-limiting factor in milk production. To examine GLUT12’s expression and facilitate the study of GLUT12’s potential role in supporting milk synthesis in lactating bovine mammary gland, bovine GLUT12 was cloned and its distribution of mRNA expression in bovine tissues was examined. The full-length mRNA of bGLUT12 is 2423 base pairs long and is predicted to encode a protein of 621 amino acids with a molecular weight of approximately 67 kDa. The deduced amino acid sequence of bovine GLUT12 is 87% and 82% identical to the sequences of human and mouse GLUT12. The sequence of bGLUT12 contains several characteristically conserved sugar transporter family signatures. Analysis of current bovine genomic data indicates that bovine GLUT12 gene consists of five exons. The major in vitro transcription and translation product of bovine GLUT12 cDNA migrated at an apparent molecular weight of 41 kDa. In the presence of canine microsomal membranes, the translation product increased to 43 kDa, suggesting glycosylation. GLUT12 mRNA was found in all bovine tissues examined, but most abundant in bovine spleen and skeletal muscle, at intermediate levels in bovine kidney, testes, and mammary gland, and at lower levels in bovine liver, lung and intestine. Immunofluorescence staining showed that, in the presence of insulin, bGLUT12 is mainly distributed in the cytoplasm of the transiently transfected MAC-T bovine mammary epithelial cells. The nucleotide sequence data reported in this paper have been submitted to GenBank with assigned accession number AY514443.
(26-Jan-2006)
 

Abbasi, A.R., Ihara, N., Watanabe, T., Khalaj, M., Tsuji, T., Sugimoto, Y., Kunieda, T. 2005. "Linkage mapping of the locus responsible for congenital multiple ocular defects in cattle on bovine Chromosome 18". Mammalian Genome, 16: 731 – 737.

KEYWORDS: congenital multiple ocular defects, cattle
SUMAMRY: Congenital multiple ocular defects (MOD) in Japanese black cattle is a hereditary ocular disorder with an autosomal recessive manner of inheritance, showing developmental defects of the lens, retina, and iris, persistent embryonic eye vascularization, and microphthalmia. In the present study, the locus responsible for the disorder was mapped by linkage analysis using 240 microsatellite markers covering the entire bovine genome and an inbred pedigree obtained from commercial herds. The linkage analysis demonstrated a significant linkage between the disorder locus and markers on the proximal region of bovine chromosome (BTA) 18 with the maximum LOD score of 5.1. Homozygosity mapping using the haplotype of the linked markers further refined the critical region. The results revealed the localization of the locus responsible for MOD in an approximately 6.6-cM region of BTA18. Comparison of published linkage and radiation hybrid (RH) maps of BTA18 with its evolutionary ortholog, human Chromosome (HSA) 16, revealed several potential candidate genes for the disorder including the MAF and FOXC2 genes.
(26-Jan-2006)
 

Morris, C. A., Hickey, S. M., Cullen, N. G., Prosser, C. G. 2005. " Associations between β casein genotype and milk yield and composition in grazing dairy cows". New Zealand Journal of Agricultural Research, 48: 441–450

KEYWORDS: milk composition; β casein; genotype; cattle.
SUMAMRY: Milk samples from New Zealand dairy cows at pasture were analysed to investigate the relationship between β casein genotype and milk yield or composition traits. A total of 1661 milk samples from 21 North Island herds were analysed from individual cows in mid lactation, from a routine herd-test taken between mid November 2000 and early February 2001. The cows, whose ages ranged from 2 to 11 years, were the daughters of 11 widely used Holstein-Friesian bulls. The β casein genotypes of the sires (A1 or A2 alleles) were: A1A1 (n = 1), A1A2 (n = 7) and A2A2 (n = 3). The milk composition traits analysed were: protein%, fat%, somatic cell count (SCC), β casein%, κ casein%, β lactoglobulin%, lactoferrin%, and fatty acid composition (C4–C24, including conjugated linoleic acid). Milk yield per day, fat colour (optical density measurement), milkfat melting point, and an index of milk value in dollars (combining the industry’s economic values for milk yield, fat yield, and protein yield) were also analysed. Sire effects were significant for most of the traits. Linear contrasts were calculated between β casein genotypes on a pooled within sire basis for each trait. Expressing results relative to the mean of all samples analysed, there was a significant increase of 2.8% (±1.2%) in the daily fat yield of A2A2 over A1A2 genotype cows (P < 0.05), and the data suggested an increase (P < 0.10) in daily protein yield (a 2.2% margin of A2A2 over A1A1 genotypes, and a 1.9% margin of A2A2 over A1A2 genotypes). Milk solids yield was affected in a similar way to milk protein and milk fat yields. Milk value per day was significantly increased by 2.0% (±1.0%) in A2A2 cows over A1A2 cows (P < 0.05). β casein% and κ casein% were significantly lower in A2A2 than A1A1 genotypes, by 4.3% (±1.0%) (P < 0.001) and 4.5% (±2.0%) (P < 0.05) of their respective mean concentrations, with values in the A1A2 genotype being intermediate and significantly greater than in the A2A2 genotype (P < 0.05) for both β casein% and κ casein%. There was a lower percentage of medium-chain fatty acids and a corresponding increase in long-chain mono-unsaturated fatty acids in the milk of A2A2 than of A1A1 cows (P < 0.05), whilst milk from A1A2 and A2A2 cows was similar in this respect. There was a significantly higher SCC (P < 0.05) for the A1A2 than the A1A1 genotypes, but the percentage of cows whose milk exceeded an SCC of 400 000 cells/ml was not significantly affected by β casein genotype. No other measured differences were significant. Overall, the milk value per day from A2A2 cows was worth 2.1% more (±0.95%) than that from A1A1 and A1A2 cows together (P < 0.05). Using economic values in the Breeding Worth formula for the 2004 year, this advantage was equivalent to $15.8 per lactation or $4,740 in a herd of 300 cows.
(26-Jan-2006)
 

Bueno, R. S., Torres, R. A., Renno, F. P. 2005. "Effect of sire x herd interaction on genetic values for milk and fat yields of Brown Swiss breed sires". Revista Brasileira de Zootecnia, 34:1156-1164.

KEYWORDS: Dairy cattle; genotype by environment interaction; variance components.

SUMMARY: Records of milk and fat yields were used to study the effects of sire x herd and sire x herd-year interactions on genetic values of Brown Swiss breed sires. The (co)variance components were estimated by the restricted maximum likelihood method, by using three models with multitrait. In these models, the genetic group, season of calving and herd-year class were considered as fixed effects, while the animal effects, the permanent environment, the interaction of either sire x herd or sire x herd-year were considered as random ones, when the interaction was considered in the model, and the error as well. The likelihood ratio test was used to verify the effectiveness in including the interaction effects into models. The estimates of components of the genetic addictive and residual (co)variances did not change when the models were adjusted for the interaction effects. Therefore, the heritability coefficients approximated to each others. The heritability estimate were of 0.40 for both characteristics, and the genetic correlation among the characteristics of 0.94, except when the model considered the effect of the interaction sire x herd. The heritability of fat yield was of 0.39, and the genetic correlation among the characteristics of 0.95. The proportion of the total variance explained by the sire x herd and the sire x herd -year interactions was low, but almost null for milk yield, and about 1% for fat yield. The natural logarithm of likelihood function increased, when the interaction effects were included in the models. Pearson and Spearman correlations among the genetic values obtained by these models were superior than 0.99 for both milk and fat yields, and above 0.897 among the studied characteristics.
(26-Jan-2006)
 

Giannotti, J. Di. G., Packer, I. U., Mercadante, M. E. Z. 2005. "Cluster analysis for meta-analysis implementation for heritability of estimates growth traits in beef cattle". Revista Brasileira de Zootecnia, 34:1165-1172.

KEYWORDS: Genetic parameters; multivariate analysis; pooled estimates; random effects models.

SUMMARY: Heritability estimates of growth traits are essential informations in animal breeding programs. In this paper, 869 heritability estimates of birth weight, weaning weight, weight at 365 days old and weight at 550 days old, of 186 reports were compiled. The estimates were divided in groups using the Ward method of cluster analysis, and pooled by meta-analysis. It was observed, for all traits, that groups from Nelore breed, majority in Brasil, showed greater pooled heritability estimates than the other groups. The methods, restricted maximum likelihood and DerSimonian and Laird, were used to estimate the variance between studies, where the first method showed higher variances.
(26-Jan-2006)
 

Giannotti, J. Di. G., Packer, I. U., Mercadante, M. E. Z. 2005. "Meta-analysis for heritability of estimates growth traits in beef cattle". Revista Brasileira de Zootecnia, 34:1173-1180.

KEYWORDS: Genetic parameters; pooled estimates; zebu cattle.

SUMMARY: A meta-analysis was conducted to summarize published heritability of estimates growth traits of zebu beef cattle of 186 reports. The factors affecting weighed heritability estimates were analyzed by the least square means method for a model including fixed effects. Breed and estimation method were the significant factors in the four traits (birth weight, weaning weight, weight at 365 days and weight at 550 days). Estimation method is always recommeded to summarize these estimates. The pooled heritability estimates for birth weight, weaning weight, weight at 365 days old and weight at 550 days old were 0.30±0.01, 0.23±0.01, 0.27±0.01 and 0.31±0.01, respectively. Meta-analysis techniques were recommended for polling of genetic parameters of zebu beef cattle.
(26-Jan-2006)

Casey, O.M., Morris, D.G., Powell, R., Sreenan, J.M., Fitzpatrick, R. 2005. "Analysis of gene expression in non-regressed and regressed bovine corpus luteum tissue using a customized ovarian cDNA array". Theriogenology, 64 (9): 1963-1976.

KEYWORDS: Bovine (Bos taurus); Corpus luteum; Luteolysis; cDNA array; Northern blots

SUMMARY: The lifespan of the bovine corpus luteum (CL) is an important factor in the control of normal ovarian cyclicity and the establishment and maintenance of pregnancy. There is increasing evidence that CL lifespan is regulated by alternative expression of genes that promote or inhibit luteolysis. To gain further insights into these events a 434 character ovarian cDNA array comprising genes attributed to key aspects of CL function including more than 100 anonymous expressed sequence tags (ESTs) was constructed and screened with α33P dATP labeled RNA isolated from non-regressed (n = 6) and regressed (n = 6) CL tissue. Significance analysis of microarrays (SAM) identified 15 genes that changed expression 1.7-fold or more with a false discovery rate of <5%. The differentially expressed genes encoded enzymes involved in steroid biosynthesis and oxygen radical metabolism and proteins involved in extracellular matrix remodeling, apoptosis and cell structure. Results for five of the differentially expressed genes including matrix gla protein and collagen α1(I) (extracellular matrix), glutathione-S-transferase αI (oxygen metabolism), clusterin (apoptosis) and scavenger receptor BI (steroid biosynthesis) were confirmed by Northern blot analysis and found to be significantly different (P < 0.01) between non-regressed and regressed CL tissue. Collectively this study identified genes with recognized roles in CL regression, genes with potential roles in this process and genes whose function have yet to be defined in this event.
(26-Jan-2006)
 

Orman, M.N., Ertugrul, O., Alpan, O. 2005. "Some Productive Characteristics of F1, B1 and F1XB1 Crossbreeds from Simmental x SAR Crossbreeding". Turkish Journal of Veterinary and Animal Science, 29,: 1129-1135.

KEYWORDS: Cattle, Simmental, South Anatolian Red, crossing, reproduction, milk production

SUMMARY: South Anatolian Red (SAR) cattle are well adapted to the arid, hot and harsh conditions of the region and have the highest milk yield among the local breeds in Turkey. The purpose of this study was to determine the main productive characteristics, such as viability, reproduction and milk production, of F1, B1 and F1XB1 crossbred genotype groups from Simmental x SAR crossbreeding. A t test was used for 2 group comparisons. In cases of insufficient numbers of variants in the groups Kruskal-Wallis and Mann-Whitney U tests were used where appropriate. There was no difficulty during birth in any of the crossbred groups. Viability rates for males were 100% in the B1 and 97.3% in the F1xB1 crossbred groups and 92.3% in the B1 and 94.6% in the F1xB1 groups for females. The average milk yields of the F1 and B1 genotype groups were similar to those of SAR. However, there were sizeable variations in the genotype groups for milk production, indicating that selection for milk yield is highly promising. In conclusion the crossbreeding programme would be beneficial for viability and possibly for milk production.
(26-Jan-2006)
 

Nguyen, T. T., Genini, S., Ménétrey, F., Malek, M., Vögeli, P., Goe, M. R., Stranzinger, G. 2005. "Application of bovine microsatellite markers for genetic diversity analysis of Swiss yak (Poephagus grunniens)". Animal Genetics, 36 (6): 484-489.

KEYWORDS: Bovine, cross-species amplification, genetic diversity, microsatellites, parentage, Poephagus grunniens, polymorphism, yak

SUMMARY: In order to assess the applicability of bovine microsatellite markers for population genetic studies in Swiss yak, 131 bovine microsatellite markers were tested on a panel of 10 animals. Efficient amplification was observed for 124 markers (94.6%) with a total of 476 alleles, of which 117 markers (94.3%) were polymorphic. The number of alleles per locus among the polymorphic markers ranged from two to nine. Seven loci (ILSTS005, BMS424B, BMS1825, BMS672, BM1314, ETH123 and BM6017) failed to amplify yak genomic DNA. Two cattle Y-chromosome specific microsatellite markers (INRA126 and BM861) amplified genomic DNA from both male and female yaks. However, two additional markers on cattle Y-chromosome (INRA124 and INRA189) amplified DNA from only males. Of the polymorphic markers, 24 microsatellites proposed by CaDBase for within- and cross-species comparisons and two additional highly polymorphic markers (MHCII and TGLA73) were used to investigate the genetic variability and the population structure of a Swiss yak herd that included 51 additional animals. The polymorphic information content ranged from 0.355 to 0.752, while observed heterozygosity (HO) ranged from 0.348 to 0.823. Furthermore, a set of 13 markers, organized into three multiplex polymerase chain reactions, was evaluated for routine parentage testing. This set provided an exclusion probability in a family of four yaks (both parents and two offspring) of 0.995. These microsatellites serve as useful tools for genetic characterization of the yak, which continues to be an important domestic livestock species.
(26-Jan-2006)

Altarriba, J., Varona, L., Moreno, C., Yagüe, G., Sañudo, C. “Consequences of selection for growth on carcass and meat quality in Pirenaica cattle”. 2005. Livestock Production Science. 95: 103-114.

KEYWORDS: Correlated response, Growth, Carcass quality, Meat quality, Beef cattle.

SUMMARY The male progeny of nine bulls used in artificial insemination were sampled to determine the effects of selection for weight at 210 days of age (W210) on carcass and meat quality in the Pirenaica cattle breed. For each of the 125 male offspring raised in experimental conditions, we measured 38 variables (y) defining carcass and meat quality. In turn, the breeding values of those animals for the W210 trait (û210) were calculated without their own record and without data of maternal siblings. Indirect responses were estimated from the slope of the covariate between the selection index (û210) and the phenotype of those variables (b(y, û210)). We derived that the covariate depends on the genetic correlation and the genetic variances of the selection index and the trait. Consequently, this method provides an unbiased estimator of the correlated response, without requiring an estimate of the genetic correlation. We conclude that, in the Pirenaica breed, selection for W210 produces animals with higher live- and carcass weights at slaughter, wider carcasses, deeper and longer legs with a greater perimeter, and greater loin surface. Genetic changes were not detected in dressing percentage and physicochemical or sensorial parameters of meat quality.
(6-Sept-2005)
 
 

Phocas, F., Donoghue, K., Graser, H.U. 2005. "Investigation of three strategies for an international genetic evaluation of beef cattle weaning weight". Genetic Selection Evolution, 37: 361-380.

KEYWORDS: Limousine cattle, animal model, MACE, genetic parameters

SUMMARY: Weaning weights from 83 389 Limousine calves born between 1993 and 2002 in France and the Trans-Tasman block (Australia / New Zealand) were analysed to compare different strategies for running an international genetic evaluation for the breed. These records were a subset of the complete data for both countries and comprised a sample of herds that had recorded progeny of sires used across both countries. Genetic and phenotypic parameters for weaning weight were estimated within the countries. The estimates of direct genetic heritabilities were higher in France than in the Trans-Tasman block (0.31 vs. 0.22), while direct-maternal genetic correlations were less negative in the Trans-Tasman block (-0.10) than in France (-0.21). Different strategies for an international evaluation were studied, and the correlations between the estimated breeding values (EBV) of national evaluations and these strategies were derived. The international evaluation strategies were a) an animal model on raw performance data with non unity genetic correlations and heterogeneous residual and genetic variances across countries; b) the same animal model applied to pre-corrected (for fixed effects) performance data; and c) a sire model on de-regressed proofs (MACE). Estimates of the genetic correlations between weaning weight in both countries were 0.86 (0.80) for direct (maternal) genetic effects for the first strategy. Estimation of variance components by MACE appeared to be very sensitive to the sample of bulls and their reliability approximations. Variance component estimates obtained using pre-corrected data were inconsistent with estimates on raw data. However, the EBV predicted using pre-corrected data and parameters estimated from the raw data were similar to those predicted from raw data. Correlations between national and international EBV were always high (>0.90) for sires, whichever genetic effect (direct or maternal) or international evaluation model was considered. The ranking of the bulls in the top 100 is of primary interest in terms of international genetic evaluation. In this study, some re-ranking of sires was observed for the top 100 bulls between countries and between the three international evaluation models. Thus, the origin of top sires may vary according to the implemented international evaluation strategy.
(6-Sept-2005)
 
 

Detilleux, J.C. 2005. "Genetic management of infectious diseases: a heterogeneous epidemio-genetic model illustrated with S. aureus mastitis". Genetic Selection Evolution, 37: 437-453.

KEYWORDS: Infectious disease resistance, heterogeneous SIS model, genetic management, mastitis.

SUMMARY: Given that individuals are genetically heterogeneous in their degree of resistance to infection, a model is proposed to formulate appropriate choices that will limit the spread of an infectious disease. The model is illustrated with data on S. aureus mastitis and is based on parameters characterizing the spread of the disease (contact rate, probability of infection after contact, and rate of recovery after infection), the demography (replacement and culling rates) and the genetic composition (degree of relationship and heritability of the disease trait) of the animal population. To decrease infection pressure, it is possible to apply non-genetic procedures that increase the culling (e.g., culling of chronically infected cows) and recovery (e.g., antibiotic therapy) rates of infected cows. But the contribution of the paper is to show that genetic management of infectious disease is also theoretically possible as a control measure complementary to non-genetic actions. Indeed, the probability for an uninfected individual to become infected after contact with an infected one is partially related to their degree of kinship: the more closely they are related, the more likely they are to share identical genes like those associated to the non-resistance to infection. Different prospective genetic management procedures are proposed to decrease the contact rate between infected and uninfected relatives and keep the number of secondary cases generated by one infected animal below.
(6-Sept-2005)
 
 

Jiang, Z., De, S., Garcia, M.D., Griffin, K.B., Wu, X.-L., Xiao, Q., Michal, J.J., Sharma, B.S., Jansen, G.B. 2005. "An independent confirmation of a quantitative trait locus for milk yield and composition traits on bovine chromosome 26". Journal of Animal Breeding and Genetics, 122 (4): 281-284.

KEYWORDS: Quantitative trait loci, milk yield, milk composition, dairy cattle.

SUMMARY: Several reports have demonstrated that bovine chromosome 26 (BTA26) harbours significant or suggestive quantitative trait loci (QTL) for milk production and composition traits in dairy cattle. It was shown that a C/T substitution in the bovine TCF7L2 gene on BTA26 was significantly linked to QTL for protein yield (PY) in a Canadian dairy cattle population. Actually, this polymorphism was one of the markers derived from a genome-wide screening of QTL for milk PY using an amplified fragment length polymorphism technique combined with a DNA pooling strategy. In the present study, 990 Holstein bulls with complete genotype and phenotype data from 14 sire families were analysed to confirm, if the QTL effects exist in other populations. Statistical analysis revealed that this marker was significantly associated with PY, protein percentage, milk yield and fat yield (FY) (p < 0.001) in the US Holstein population. These results indicate that this QTL region has a pleiotrophic effect on different milk traits and is portable in different populations.
(6-Sept-2005)
 
 

Curi, R.A., de Oliveira, H.N., Silveira, A.C., Lopes, C.R. 2005. "Association between IGF-I, IGF-IR and GHRH gene polymorphisms and growth and carcass traits in beef cattle". Livestock Production Science, 94 (3): 159-167.

KEYWORDS: Beef cattle, polymorphisms, candidate gene, growth, carcass.

SUMMARY: Molecular biology techniques are of help in genetic improvement since they permit the identification, mapping and analysis of polymorphisms of genes encoding proteins that act on metabolic pathways involved in economically interesting traits. The somatotrophic axis, which essentially consists of growth hormone releasing hormone (GHRH), growth hormone (GH), insulin-like growth factors I and II (IGF-I and IGF-II), and their associated binding proteins and receptors (GHRHR, GHR, IGF-IR and IGF-IIR), plays a key role in the metabolism and physiology of mammalian growth. The objectives of the present study were to estimate the allele and genotype frequencies of the IGF-I/SnaBI, IGF-IR/TaqI and GHRH/HaeIII gene polymorphisms in different genetic groups of beef cattle and to determine associations between these polymorphisms and growth and carcass traits. For this purpose, genotyping was performed on 79 Nellore animals, 30 Canchim (5/8 Charolais+3/8 Zebu) animals and 275 crossbred cattle originating from the crosses of Simmental (n=30) and Angus (n=245) sires with Nellore females. In the association studies, traits of interest were analyzed using the GLM procedure of SAS and least square means of the genotypes were compared by the Tukey test. Associations of IGF-I/SnaBI genotypes with body weight and subcutaneous backfat were significant (p<0.05), and nearly significant for longissimus dorsi area (p=0.06), with the BB genotype being favorable compared to the AB genotype. No significant associations were observed between this polymorphism and weight gain or carcass yield (P>0.05). The IGF-IR/TaqI and GHRH/HaeIII polymorphisms showed no association with production traits.
(6-Sept-2005)
 
 

Altarriba, J., Varona, L., Moreno, C., Yagüe, G., Sañudo,, C. 2005. "Consequences of selection for growth on carcass and meat quality in Pirenaica cattle". Livestock Production Science, 95 (1-2): 103-114.

KEYWORD: Correlated response, growth, carcass quality, meat quality, beef cattle.

SUMMARY: The male progeny of nine bulls used in artificial insemination were sampled to determine the effects of selection for weight at 210 days of age (W210) on carcass and meat quality in the Pirenaica cattle breed. For each of the 125 male offspring raised in experimental conditions, we measured 38 variables (y) defining carcass and meat quality. In turn, the breeding values of those animals for the W210 trait (û210) were calculated without their own record and without data of maternal siblings. Indirect responses were estimated from the slope of the covariate between the selection index (û210) and the phenotype of those variables (b(y, û210)). We derived that the covariate depends on the genetic correlation and the genetic variances of the selection index and the trait. Consequently, this method provides an unbiased estimator of the correlated response, without requiring an estimate of the genetic correlation. We conclude that, in the Pirenaica breed, selection for W210 produces animals with higher live- and carcass weights at slaughter, wider carcasses, deeper and longer legs with a greater perimeter, and greater loin surface. Genetic changes were not detected in dressing percentage and physicochemical or sensorial parameters of meat quality.
(6-Sept-2005)
 
 

Goshu, G. 2005. "Breeding efficiency, lifetime lactation and calving performance of Friesian-Boran crossbred cows at Cheffa farm, Ethiopia". Livestock Research for Rural Development. Volume 17, Article #73. http://www.cipav.org.co/lrrd/lrrd17/7/gosh17073.htm

KEYWORDS: Breeding efficiency, cattle, crossbreeds, herd life, season

SUMMARY: Records of 602 cows maintained at Cheffa farm from 1976 to 1997 were used to analyze the variables breeding efficiency, herd life, and effective productive herd life, number of parity completed, number of calves produced and lifetime milk yield. The fixed factors considered were four levels of Friesian inheritance, three levels of season of birth or calving, nine levels of parity and 21 levels of year. General Linear Model was used to estimate the effect of independent factors. The overall mean for breeding efficiency was 66.3±0.49 and affected significantly (P<0.001) by all factors. The overall mean for herd life and effective productive herd life were 2858±57.3 and 1301±47.6 days, respectively. Level of Friesian inheritance and year of birth effected significantly (P<0.001) both traits. The overall mean for initiated parity and number of calves produced were 4.23±0.12 and 3.58±0.13, respectively and affected (P<0.001) by level of inheritance and birth year of the cow but not by season of birth. Lifetime milk yield was 12749±483kg and significantly affected (P<0.001) by level of inheritance and year of birth. Season of birth did not affect the trait significantly. The study showed that the F1 and 3/4Friesian inheritance cows had performed better than 15/16 groups. Breeding efficiency and lifetime productivity can be improved by placing efficient reproduction, feeding and health management at the farm.
(6-Sept-2005)
  

Girardi Figueiredo, L. G., Pereira Eler, J., Barreto Mourão, G., Sterman Ferraz J. B., de Carvalho Balieiro, J. C. Chicarone de Mattos, E. 2005. "Genetic analyses of temperament in a population of the Nellore breed". Livestock Research for Rural Development. Volume 17, Art. #84. http://www.cipav.org.co/lrrd/lrrd17/7/gira17084.htm

KEYWRODS: Beef cattle, genetic parameters, temperament, weight

SUMMARY: Data from 5,754 records of visual appraisal for temperament of a Nelore herd were used to estimate heritability and it's genetic correlations with growth traits. The animal model included as fixed effects, contemporary groups and, as covariate, age at measurement. Direct genetic and residual effects were considered as random effects. The estimates of heritability varied from 0.16 to 0.17 in different analysis. Genetic correlation between temperament and weight in different ages was estimated in -0.04 at birth, 0.04 at 4 months, 0.36 at weaning, 0.44 at yearling, and 0.38 at 18 months of age. Genetic correlation between temperament and weight gain from weaning to yearling age was estimated in 0.09 and 0.20 for gain from weaning to 18 month of age. The estimates indicate that temperament can be improved by selection, mainly by selecting sires with more accurate genetic predictions.
(6-Sept-2005)
 
 

Plasse, D., Bauer, B., Galdo, E., Verde, O. 2005. "Production of two composite beef cattle herds of Zebu x Criollo Yacumeño and Charolais x Zebu x Criollo Yacumeño on floodable savanna in Beni, Bolivia I. Weaning weights". Livestock Research for Rural Development. Volume 17, Article #82.  http://www.cipav.org.co/lrrd/lrrd17/7/plas17082.htm

KEYWORDS: Beef cattle, composite herds, tropics, weaning weight

SUMMARY: The objective of this study was to evaluate three generations of weaning weights (WW) of calves produced by two composite herds founded in 1975 at a private ranch in Beni, Bolivia: Herd A with F1 Zebu x Criollo cows and bulls and Herd B with 1/2Charolais1/4Zebu1/4Criollo, F1 Zebu x Criollo and 3/4Zebu1/4Criollo cows bred to 1/2Charolais1/4Zebu1/4Criollo bulls. Both herds were maintained on floodable savanna and calves were weaned at 8 months. Non-adjusted and least squares means for 8160 WW of Herd A were 177.4±0.3 and 175.1±0.7 kg at an age of 248±0.3 days and for 5654 weights of Herd B 174.5±0.4 and 174.0±0.8 kg at 250±0.3 days. Generation (G; n = 3) was an important (P<0.01) effect in Herd A but non-significant (P>0.05) in herd B. Sex (2), birth year (9), month of birth (5), age of dam in years (11), time of fasting (7 six-hour intervals) and age of calf (days, linear) were important (P<0.01) in both herds. Year x month was highly significant (P<0.01) in both herds and sex x year in Herd A (P<0.01) but not in B (P>0.05). Generation x sex was important (P<0.05) only in Herd A. WW of G2 calves (offspring of foundation cows and bulls) in Herd A was highest and decreased 10.5 kg (6 %) in G3. Herd A calves of G2, G3 and G4 showed a 4.5, -2.5 and 0 % deviation from WW of Herd B calves. While in Herd A F1 cows weaned the heaviest calves and there was an important decrease of weights in G3, in Herd B means of all three generations did not differ significantly. Adjusted means over all generations of both herds were similar. The mean adjusted WW of G3 and G4 of herds A and B did not show an advantage of economic importance over that published from the same ranch of a Zebu herd under selection.
(6-Sept-2005)
 

Plasse, D., Galdo, E., Bauer, B., Verde, O. 2005. "Production of two composite beef cattle herds of Zebu x Criollo Yacumeño and Charolais x Zebu x Criollo Yacumeño on floodable savanna in Beni, Bolivia. II. Cow performance". Livestock Research for Rural Development. Volume 17, Article #83. http://www.cipav.org.co/lrrd/lrrd17/7/plas17083.htm 

KEYWORDS: Beef cattle, composite herds, pregnancy percentage, total production, weaning percentage.

SUMMARY: The objective of the present study was to evaluate pregnancy (P) and weaning (W) status as well as weight weaned per cow in the herd (WWCH) over four generations of two composite herds founded in 1975 at a private ranch on floodable savanna in Beni, Bolivia: Herd A with F1 Zebu x Criollo cows and bulls and Herd B with 1/2Charolais1/4Zebu1/4Criollo, F1 Zebu x Criollo and 3/4 Zebu x 1/4Criollo cows bred to 1/2 Charolais x 1/4 Zebu x 1/4Criollo bulls. They were maintained in multi-sire herds on native grass in a 4-month breeding season and their calves weaned and weighed at 8 months. Pregnancy (P) and weaning (W) status was classified 0 (failure) and 1 (success) and analyzed by least squares procedures. WWCH was calculated from the respective adjusted means. The analysis included 19483 and 13051 cow-years for herds A and B, respectively. The effect of generation (G; n = 4) was significant for P and W in Herd A (P<0.01) and Herd B (P<0.05). Year of breeding season (n = 14) and age class of dam (n = 11) were important (P<0.01) in both herds for both traits. Non-adjusted and adjusted means in Herd A were: P, 80.6±0.28, and 79.6±0.89%; W, 72.0±0.36 and 72.2±1.04%; WWCH: 126.4 kg at 248±0.3 days; and in Herd B: P, 77.6±0.37 and 79.6±1.13%; W, 66.4±0.47 and 68.8±1.32%; WWCH, 119.4 kg at 250±0.3 days. In Herd A, F1 (G1, foundation cows) had 88.1% P which decreased 11% in G2 and a further 5% in G3. In Herd B, P in G1 was 83.0% and decreased 5% in G2 and a further 3% in G3. W behaved similarly. In Herd A WWCH declined 19% from G1/2 (foundation cows with progeny) to G2/3 and 6% in Herd B. The adjusted mean WWCH over all generation was 5.9 % greater in Herd A than in Herd B. Between G1/2 and the mean of G2/3 and G3/4 there was a great decrease of 18 and 8 % in WWCH in Herds A and B respectively. When comparing the mean WWCH of composites in G2/3 and G3/4 to results published from a selected Zebu herd at the ranch in the same years, Herd A and Herd B had a 3 % and 6 % lower output, allowing the conclusion that neither of the composite herds proved to be an alternative for weaner production under the prevailing conditions, compared to Zebu with a modern selection program.
(6-Sept-2005)
 
 

Roso, V. M., Schenkel, F. S., Miller, S. P., Wilton, J. W. 2005. "Additive, dominance, and epistatic loss effects on preweaning weight gain of crossbred beef cattle from different Bos taurus breeds" Journal of Animal Science, 83:1780-1787

KEYWORDS: Beef Cattle, Epistatic Loss, Genetic Parameters, Heterosis

SUMMARY: (Co)variance components, direct and maternal breed additive, dominance, and epistatic loss effects on preweaning weight gain of beef cattle were estimated. Data were from 478,466 animals in Ontario, Canada, from 1986 to 1999, including records of both purebred and crossbred animals from Angus, Blonde d’Aquitaine, Charolais, Gelbvieh, Hereford, Limousin, Maine-Anjou, Salers, Shorthorn, and Simmental breeds. The genetic model included fixed direct and maternal breed additive, dominance, and epistatic loss effects, fixed environmental effects of age of the calf, contemporary group, and age of the dam x sex of the calf, random additive direct and maternal genetic effects, and random maternal permanent environment effects. Estimates of direct and maternal additive genetic, maternal permanent environmental and residual variances, expressed as proportions of the phenotypic variance, were 0.32, 0.20, 0.12, and 0.52, respectively. Correlation between direct and maternal additive genetic effects was –0.63. Breed ranking was similar to previous studies, but estimates showed large SE. The favorable effects of direct and maternal dominance (P < 0.05) on preweaning gain were equivalent to 1.3 and 2.3% of the phenotypic mean of purebred calves, respectively. The same features for direct and maternal epistatic loss effects were –2.2% (P < 0.05) and –0.1% (P > 0.05). The large SE of breed effects were likely due to multicollinearity among predictor variables and deficiencies in the dataset to separate direct and maternal effects and may result in a less reliable ranking of the animals for across breed comparisons. Further research to identify the causes of the instability of estimates of breed additive, dominance, and epistatic loss genetic effects, and application of alternative statistical methods is recommended.
(6-Sept-2005)
 
 

Roso, V. M., Schenkel, F. S., Miller,,, S. P., Schaeffer, L. R. 2005. "Estimation of genetic effects in the presence of multicollinearity in multibreed beef cattle evaluation". Journal of Animal Science, 83:1788-1800

KEYWORDS: Crossbreeding, Dominance, Epistatic Loss, Genetic Evaluation, Ridge Regression

SUMMARY: Breed additive, dominance, and epistatic loss effects are of concern in the genetic evaluation of a multibreed population. Multiple regression equations used for fitting these effects may show a high degree of multicollinearity among predictor variables. Typically, when strong linear relationships exist, the regression coefficients have large SE and are sensitive to changes in the data file and to the addition or deletion of variables in the model. Generalized ridge regression methods were applied to obtain stable estimates of direct and maternal breed additive, dominance, and epistatic loss effects in the presence of multicollinearity among predictor variables. Preweaning weight gains of beef calves in Ontario, Canada, from 1986 to 1999 were analyzed. The genetic model included fixed direct and maternal breed additive, dominance, and epistatic loss effects, fixed environmental effects of age of the calf, contemporary group, and age of the dam x sex of the calf, random additive direct and maternal genetic effects, and random maternal permanent environment effect. The degree and the nature of the multicollinearity were identified and ridge regression methods were used as an alternative to ordinary least squares (LS). Ridge parameters were obtained using two different objective methods: 1) generalized ridge estimator of Hoerl and Kennard (R1); and 2) bootstrap in combination with cross-validation (R2). Both ridge regression methods outperformed the LS estimator with respect to mean squared error of predictions (MSEP) and variance inflation factors (VIF) computed over 100 bootstrap samples. The MSEP of R1 and R2 were similar, and they were 3% less than the MSEP of LS. The average VIF of LS, R1, and R2 were equal to 26.81, 6.10, and 4.18, respectively. Ridge regression methods were particularly effective in decreasing the multicollinearity involving predictor variables of breed additive effects. Because of a high degree of confounding between estimates of maternal dominance and direct epistatic loss effects, it was not possible to compare the relative importance of these effects with a high level of confidence. The inclusion of epistatic loss effects in the additive-dominance model did not cause noticeable reranking of sires, dams, and calves based on across-breed EBV. More precise estimates of breed effects as a result of this study may result in more stable across-breed estimated breeding values over the years.
(6-Sept-2005)
 
 

Berry, D. P., Harris, B. L., Winkelman, A. M., Montgomerie, W. 2005. "Phenotypic Associations Between Traits Other than Production and Longevity in New Zealand Dairy Cattle". Journal of Dairy Science, 88:2962-2974

KEYWORDS: Survival analysis, longevity, New Zealand, dairy

SUMMARY: A proportional hazards model was used to investigate the phenotypic effect of traits other than production (TOP) on true and functional longevity across purebred and crossbred Holstein-Friesian and Jersey dairy cattle in registered and commercial herds in New Zealand. The hazard function was described as the product of a baseline hazard function and the time-independent effects of age at first calving, heterosis, proportion of breed, period of last calving relative to herdmates, and TOP; a time-dependent effect of herd-year was also included. The influence of TOP on functional longevity was assessed by adjusting true longevity for the time-independent effects of production values as well as the time-dependent effects of deviation of milk, fat, and protein yield within contemporary group. All analyses were stratified by breed, and separate analyses were carried out for registered or commercial herds. All TOP were significantly related to true and functional longevity. Obvious differences existed in the relative influence of individual TOP on longevity in registered or commercial herds. Of the individual TOP describing the physical characteristics of the cow, the udder-related TOP exhibited the largest influence on functional longevity. Farmer opinion explained the largest proportion of variation in true and functional longevity among cows. In commercial herds, the risk of culling in cows with very low farmer opinion was 1.5 to 2.0 times that in cows with average or high farmer opinion.
(6-Sept-2005)
 
 

Bennewitz. J., Meuwissen, T. H. E. 2005. "Estimation of Extinction Probabilities of Five German Cattle Breeds by Population Viability Analysis". Journal of Dairy Science, 88:2949-2961

KEYWORDS: Extinction probability, population viability analysis, livestock breed, genetic diversity

SUMMARY: The estimation of the expected loss of genetic diversity and marginal diversities in a set of breeds within a defined future time horizon requires initial estimates of breed extinction probabilities. In this study, the extinction probabilities of 5 German dual-purpose cattle breeds were estimated by population viability analysis. Regression was used to estimate the infinitesimal mean and variance of the population growth and this was based on the diffusion approximation of the density independent population growth (also known as the Dennis regression model). The annual number of milk-recorded cows in each breed was used as census data. Based on the regression results, the extinction probabilities and their confidence intervals were estimated for a wide variety of future time horizons using Monte Carlo time series simulations. The estimates of extinction probabilities were sensible, but in 2 cases they depended heavily on the time horizon considered. Additionally, the confidence intervals became very wide with an increased time horizon. We recommend the estimation of extinction probabilities for a set of future time horizons rather than for a single future time and the selection of an upper bound for this set that is not too large to be meaningful. The validity of the use of the number of milk-recorded cows as census data and of the model assumptions is discussed in detail.
(6-Sept-2005)
 
 

“Denny” Crews, D.H. Jr. 2005. "Genetics of efficient feed utilization and national cattle evaluation: a review". Genetics and Molecular Research, 4 (2): 152-165.

KEYWORDS: Beef cattle, Feed efficiency, Genetic evaluation

SUMMARY: Selection for the wide range of traits for which most beef breed associations calculate expected progeny differences focus on increasing the outputs of the production system, thereby increasing the genetic potential of cattle for reproductive rates, weights, growth rates, and end-product yield. Feed costs, however, represent a large proportion of the variable cost of beef production and genetic improvement programs for reducing input costs should include traits related to feed utilization. Feed conversion ratio, defined as feed inputs per unit output, is a traditional measure of efficiency that has significant phenotypic and genetic correlations with feed intake, growth rate, and mature size. One limitation is that favorable decreases in feed to gain either directly or due to correlated response to increasing growth rate do not necessarily relate to improvement in efficiency of feed utilization. Residual feed intake is defined as the difference between actual feed intake and that predicted on the basis of requirements for maintenance of body weight and production. Phenotypic independence of residual feed intake with growth rate, body weight, and other energy depots can be forced. However, genetic associations may remain when a phenotypic prediction approach is used. Heritability estimates for phenotypic residual feed intake have been moderate, ranging from 0.26 to 0.43. Genetic correlations of phenotypic residual feed intake with feed intake have been large and positive, suggesting that improvement would produce a correlated response of decreased feed intake. Residual feed intake estimated by genetic regression results in a zero genetic correlation with its predictors, which reduces concerns over long-term antagonistic responses such as increased mature size and maintenance requirements. The genetic regression approach requires knowledge of genetic covariances of feed intake with weight and production traits. Cost of individual feed intake measurements on potential replacements must be considered in implementation of national cattle evaluations for efficiency of feed utilization. These costs need to be compared to expected, and, if possible, realized rates of genetic change and the associated reduction in feed input requirements.
(6-Sept-2005)
 
 

Cobanoglu O., Berger P. J., Kirkpatrick B. W. (2005) “Genome screen for twinning rate QTL in four North American Holstein families.” Animal Genetics 36, 303-308.

KEYWORDS: dairy cattle, microsatellite, quantitative trait loci, selective DNA pooling, twinning rate.

SUMMARY: This work aimed to investigate twinning rate quantitative trait loci (QTL) by typing pooled samples in a preliminary screening followed by interval mapping to test QTL effects. Four elite North American Holstein half-sib sire families with high twinning rate predicted transmitting abilities (PTA) were used in this study. Chromosomes 5, 7, 19 and 23 were not genotyped as these chromosomes were scanned for QTL in these families in a previous study. DNA was extracted from phenotypically extreme sons in each sire family. Two pools were prepared from sons of sires in each phenotypic tail, two each for high and low PTA levels for twinning rates. Each pool contained DNA from 4 to 15% of all sons of the sire depending on family. A total of 268 fluorescently labelled microsatellite markers were tested for heterozygosity in sires. About 135–170 informative markers per family were genotyped using pooled DNA samples. Based on the preliminary evidence for potential twinning rate QTL from pooled typing, interval mapping was performed subsequently on 12 chromosomal regions by family combinations. Evidence of QTL for twinning rate was found in one family on BTA21 and 29 at a chromosome-wide P < 0.05 and on BTA8, 10 and 14 with a chromosome-wide P < 0.01.
(6-Sept-2005)
 

Oltenacu P.A., Algers B. (2005) “Selection for increased production and the welfare of dairy cows: Are new breeding goals needed?”. Ambio 34:311-315.

KEYWORDS: dairy cattle; public acceptance; welfare; genetic selection

SUMMARY: In many European countries, milk production per cow has more than doubled in the last 40 years. The increase in production has been accompanied by declining ability to reproduce, increasing incidence of health problems, and declining longevity in modern dairy cows. Genetic selection for increased milk yield increasingly is viewed as increasing profit at the expense of reducing animal welfare. The economic future of the dairy industry is related directly to public acceptance of its breeding and production practices. It is important to the dairy industry that welfare problems should be addressed before there is widespread condemnation of breeding and management practices. A new breeding goal aimed at improving fitness and tolerance of metabolic stress is necessary to prevent the decrease in the quality of life of dairy cows.
(6-Sept-2005)
 
 

Odegard J., Madsen P., Gianola D., Klemetsdal G., Jensen J., Heringstad B., Korsgaard I.R. (2005) “A Bayesian threshold-normal mixture model for analysis of a continuous mastitis-related trait”. J. Dairy Sci. 88:2652-2659.

KEYWORDS: Bayesian methods; mastitis; mixture model; somatic cell score

SUMMARY: Mastitis is associated with elevated somatic cell count in milk, inducing a positive correlation between milk somatic cell score (SCS) and the absence or presence of the disease. In most countries, selection against mastitis has focused on selecting parents with genetic evaluations that have low SCS. Univariate or multivariate mixed linear models have been used for statistical description of SCS. However, an observation of SCS can be regarded as drawn from a 2- ( or more) component mixture defined by the (usually) unknown health status of a cow at the test-day on which SCS is recorded. A hierarchical 2- component mixture model was developed, assuming that the health status affecting the recorded test-day SCS is completely specified by an underlying liability variable. Based on the observed SCS, inferences can be drawn about disease status and parameters of both SCS and liability to mastitis. The prior probability of putative mastitis was allowed to vary between subgroups (e.g., herds, families), by specifying fixed and random effects affecting both SCS and liability. Using simulation, it was found that a Bayesian model fitted to the data yielded parameter estimates close to their true values. The model provides selection criteria that are more appealing than selection for lower SCS. The proposed model can be extended to handle a wide range of problems related to genetic analyses of mixture traits.
(6-Sept-2005)
 
 

Detilleux J.C. (2005) “Genetic management of infectious diseases: a heterogeneous epidemio-genetic model illustrated with S-aureus mastitis”. Genetics Selection Evolution 37:437-453.

KEYWORDS: infectious disease resistance; heterogeneous SIS model; genetic management; mastitis

SUMMARY: Given that individuals are genetically heterogeneous in their degree of resistance to infection, a model is proposed to formulate appropriate choices that will limit the spread of an infectious disease. The model is illustrated with data on S. aureus mastitis and is based on parameters characterizing the spread of the disease (contact rate, probability of infection after contact, recovery rate after infection), the demography (replacement and culling rates) and the genetic composition (degree of relationship and heritability of the disease trait) of the animal population. To decrease infection pressure, it is possible to apply non-genetic procedures that increase the culling (e.g., culling of chronically infected cows) and recovery (e.g. antibiotic therapy) rates of infected cows. But the contribution of the paper is to show that genetic management of infectious disease is also theoretically possible as a control measure complementary to non-genetic actions. Indeed, the probability for an uninfected individual to become infected after contact with an infected one is partially related to their degree of kinship; the more closely they are related, the more likely they are to share identical genes like those associated to the non-resistance to infection. Different prospective genetic management procedures are proposed to decrease the contact rate between infected and uninfected relatives and keep the number of secondary cases generated by one infected animal below 1.
(6-Sept-2005)
 
 

Calus M.P.L., Windig J.J., Veerkamp R.F. (2005) “Associations among descriptors of herd management and phenotypic and genetic levels of health and fertility”. J. Dairy Sci. 88:2178-2189.

KEYWORDS: traits; genotype-by-environment interaction; environmental sensitivity

SUMMARY: The objective was to investigate the association of descriptors of herd environment with phenotypic levels and breeding values of fertility and health traits. Analyses were