Animal nutrition - Cattle

Suárez B. J., Van Reenen C. G., Beldman G., van Delen J., Dijkstra J., Gerrits W. J. J. (2006) “Effects of Supplementing Concentrates Differing in Carbohydrate Composition in Veal Calf Diets: I. Animal Performance and Rumen Fermentation Characteristics”. Journal of Dairy Science (89), 11 pp 89: 4365-4375.

KEYWORDS: veal calf, concentrate feed composition, rumen fermentation, enzyme activity.

SUMMARY: The aim of this experiment was to examine the effects of concentrates in feed, differing in carbohydrate source, on the growth performance and rumen fermentation characteristics of veal calves. For this purpose, 160 Holstein Friesian x Dutch Friesian crossbred male calves were used in a complete randomized block design with a 5 x 2 factorial arrangement. Dietary treatments consisted of 1) milk replacer control, 2) pectin-based concentrate, 3) neutral detergent fiber-based concentrate, 4) starch-based concentrate, and 5) mixed concentrate (equal amounts of concentrates of treatments 2, 3, and 4). Concentrate diets were provided as pellets in addition to a commercial milk replacer. Calves were euthanized either at the end of 8 or 12 wk of age. The overall dry matter intake of the concentrate diets varied between 0.37 and 0.52 kg/d. Among the concentrate diets, the dry matter intake was lower in the starch diet (0.37 kg/d of dry matter) and differed between the NDF and pectin diets. The average daily gain for all the dietary treatments varied between 0.70 and 0.78 kg/d. The mixed- and NDF-fed calves had an increased average daily gain (0.78 and 0.77 kg/d, respectively) compared with the starch- and pectin-fed calves (0.70 and 0.71 kg/d, respectively). Rumen fermentation in the calves fed concentrates was characterized by a low pH (4.9 to 5.2), volatile fatty acid concentrations between 100 and 121 mmol/L, and high concentrations of reducing sugars (33 to 66 g/kg of dry matter). The volatile fatty acid concentrations of calves fed concentrates were higher than those of the control calves. All concentrate treatments showed a low acetate-to-propionate ratio in rumen fluid (between 1.3 and 1.9). Among the concentrates, the NDF diet had the highest (55.5%) and starch the lowest (45.5%) molar proportions of acetate. Calves fed the mixed, pectin, and starch diets had significantly higher molar proportions of butyrate (13.1 to 15.8%) than the NDF- and control-fed groups (9.9 and 9.6%, respectively). Calves fed the control diet had a higher lactate concentration (21 mmol/L) than the concentrate-fed calves (between 5 and 11 mmol/L). With the exception of the NDF diet, polysaccharide-degrading enzyme activities in the rumen contents generally showed an adaptation of the microorganisms to the carbohydrate source in the diet. The mixed diet exhibited the least variation in rumen polysaccharide-degrading enzyme activities among the enzymes systems tested. Results indicated that the carbohydrate source can influence intake, growth rate, and rumen fermentation in young veal calves.
(10-Dec-2006)
 

Vasconcelos J. T., Greene L. W., Cole N. A., Brown M. S., McCollum F. T., Tedeschi L. O. (2006) “Effects of phase feeding of protein on performance, blood urea nitrogen concentration, manure nitrogen:phosphorus ratio, and carcass characteristics of feedlot catte”. Journal of Animal Science, (84), 11 pp 3032-3038.

KEYWORDS: environment, feedlot, nitrogen, phase feeding, phosphorus

SUMMARY: Two experiments with a randomized complete block design were conducted to determine the effects of phase feeding of CP on performance, blood urea nitrogen (BUN), manure N:P ratio, and carcass characteristics of steers fed in a feedlot. In Exp. 1, 45 crossbred steers (initial BW = 423 ± 3.3 kg) were individually fed a diet formulated to contain 13.0% CP (DM basis) for 62 d. On d 63, the dietary CP was maintained at 13.0% or formulated to contain 11.5 or 10.0% CP until slaughter. Actual CP values were 12.8, 11.8, and 9.9%, respectively. Reducing the CP concentration of the diet did not affect ADG of steers from d 62 to 109 (P = 0.54) or over the 109-d feeding period (1.45, 1.50, and 1.49 kg/d for 13.0, 11.5, and 10.0% CP, respectively; P = 0.85). No differences (P > 0.12) among treatments were detected for BUN concentrations on d 0, 62, or 109. Gain:feed, DMI, and carcass characteristics did not differ among treatments (P > 0.10). In Exp. 2, 2 trials were conducted using 184 (initial BW = 406 ± 2.6 kg) and 162 (initial BW = 342 ± 1.9 kg) crossbred steers. Data from the 2 trials were pooled for statistical analysis, and trial effect was added to the statistical model. Steers were fed a diet formulated to contain 13.0% CP until reaching approximately 477 kg. When the average BW of the pen was 477 kg, diets were maintained at 13.0% CP or reduced to contain 11.5 or 10.0% CP. Actual CP values were 12.4, 11.5, and 9.3% CP for treatments 13.0, 11.5, and 10.0% CP, respectively. Reducing the CP content of the diet did not affect ADG after the diet changed (P = 0.16) or throughout the finishing period (P = 0.14). Immediately before slaughter, steers fed the 13.0% CP diet had greater (P < 0.001) BUN concentrations than steers fed the 11.5 and 10.0% CP diets. Carcasses from cattle fed the 11.5% CP diet had greater (P = 0.02) fat thickness than the 13.0 and 10.0% CP treatments, whereas carcasses from cattle fed 13.0% CP had greater (P = 0.004) marbling scores than steers fed the 11.5 or 10.0% CP diets. Other carcass characteristics, DMI, and G:F did not differ (P > 0.10) among treatments. The N:P ratio was increased with the 10.0% CP diet (P = 0.02) compared with the 11.5 or 13.5% CP treatments; however, manure composition did not differ (P > 0.10) among treatments. These results indicate that reduced CP concentration during the finishing period does not affect feedlot performance but can improve the N and P relationship in the manure..
(10-Dec-2006)
 

Theodorou MK, Kingston-Smith AH, Winters AL, Lee MRF, Minchin FR, Morris P, MacRae J (2006) Polyphenols and their influence on gut function and health in ruminants: a review Environmental Chemistry Letters 4 (3): 121-126

KEYWORDS: rumen; ruminant; livestock; microbiology; anaerobic; proteolysis; polyphenol oxidase; polyphenol; water-soluble carbohydrate; red-clover; dairy-cows; digestion; plant; proteolysis; herbage; protein; forage; sheep

SUMMARY: Polyphenols in plants can protect proteins from degradation and improve the efficiency of conversion of plant protein to animal protein (meat and milk), but can this be achieved in a way that is environmentally sustainable, profitable to the livestock farmer and is consistent with aspirations for improved livestock nutrition, health, welfare and product quality? Given that grazed and conserved forage is the bedrock of sustainable ruminant production, this paper attempts to consider what challenges are ahead in terms of enhancing productive efficiency, reducing the polluting footprint of livestock agriculture and alleviating the endemic parasitism that occurs with grazing animals.
(30-Nov-2006)
 

Sahlin A, House JD (2006) Enhancing the vitamin content of meat and eggs: Implications for the human diet Canadian Journal of Animal Science 86 (2): 181-195

KEYWORDS: meat; eggs; vitamin enhancement; bioavailability; dietary reference intakes; alpha-tocopheryl acetate; bacterially synthesized folate; beta-carotene supplementation; rye-based diets; folic-acid; oxidative stability; large-intestine; intramuscular injection; serum concentrations; c supplementation

SUMMARY: Enhancing the vitamin content of meat and eggs provides an opportunity to increase the levels of key nutrients-especially those deemed to be at marginal or insufficient levels-in the human diet for optimal health and well-being. In general, enhancement efforts have focussed on developing feeding strategies to achieve optimal vitamin levels in meat and eggs. The definition of an optimal strategy is influenced by factors such as: (1) the efficiency of vitamin transfer into the final product, (2) the impact on animal performance or health, (3) the impact on the quality characteristics of the final product and (4) economic considerations. Vitamins are an extremely diverse class of nutrients in terms of their chemical and physical properties. Each vitamin differs with respect to stability during processing, susceptibility to bioconversion within the intestinal tract, digestibility, transport and storage in tissues. It follows that the development of vitamin-enriched meat and eggs will be highly dependent on the interaction of multiple factors. Ultimately, the success of such strategies must be judged against the contributions that the enriched products make to the human diet in terms of vitamin intake and consumer acceptance of the products.
(30-Nov-2006)
 

Lozier J, Rayburn E, Shaw J (2006) The decision to finish cattle on pasture: An ethnographic approach Journal of Sustainable Agriculture 28 (3): 5-23

KEYWORDS: beef; cattle; ethnography; farm; naturalistic; niche; pasture; proficient; risk

SUMMARY: Conventional cattle enterprises send grain-finished beef to a commodity market. Pasture-finishing offers farmers better returns in an alternative "niche" market with different Costs, uncertainties and risks, Such enterprise decisions are not well-structured problems soluble with classical decision analysis. Instead, they require an ethnographic process of "framing" from a personal viewpoint. Here we examine the natural and Cultural setting of beef cattle enterprise systems, and their time frame for action planning and implementation. We present four brief case studies of farmers who practice pasture-finishing. An "ethnographic decision model" (EDM) asks farmers about their personal, material, social and financial resources. In behavioral decision theory, a parallel line of research is "naturalistic decision making" (NDM), focused on the proficiency of decision makers dealing with ill-structured problems, incomplete information, uncertainty, and urgency. Pasture-finished beef production can be an addition to a risk-reducing portfolio of enterprises. The key is classification of the herd into two groups, destined either for the niche market or for the commodity market. When forage growth conditions are unfavorable, the niche group receives preference and commodity animals get second best.
(30-Nov-2006)
 

Reinert ES (2006) The economics of reindeer herding - Saami entrepreneurship between cyclical sustainability and the powers of state and oligopolies British Food Journal 108 (7): 522-540

KEYWORDS: culture (sociology); government policy; meat; entrepreneurialism; Norway

SUMMARY: Purpose - This paper attempts to explain the drastic fall in income experienced by Saami reindeer herders in Nor-them Norway between 1976 and 2000, in spite of increasing government subsidies. Saami herders maintain a legal monopoly as suppliers of reindeer meat, a traditional luxury product in Norway. Design/methodology/approach - This paper shows that a review of the literature is supported by qualitative interviews. Findings - The paper argues that main explanatory variables are to be found in the interaction of a number of factors, mainly: cyclical climatic variation in Northern Norway; a system with fixed prices, independent of the variations in supply, that magnified the effects of the natural cycles; increasingly severe sanitary regulations forcing Saami herders to abandon slaughtering and preparation; and the oligopoly market powers of the non-Saami actors taking over slaughtering and processing. It is argued that the fall in herders' income resulted from a failure of the Norwegian Department of Agriculture to understand key factors distinguishing sub-Arctic herding from sedentary agriculture. Sanitary requirements and the government's quest for economies of scale in processing contributed to playing the volume of production into the hands of non-Saami oligopolies. In this way the Saami herders lost the meat production that traditionally was at the core of both their culture and their economic livelihood. Originality/value - The paper is relevant for the management of herding and other production systems in areas with cyclical production, and documents the damaging effects on the aboriginal culture resulting from Norway's exclusive use of modem agricultural science in managing such systems.
(30-Nov-2006)
 

Benchaar C, Duynisveld JL, Charmley E (2006) Effects of monensin and increasing dose levels of a mixture of essential oil compounds on intake, digestion and growth performance of beef cattle Canadian Journal of Animal Science 86 (1): 91-96

KEYWORDS: essential oils; monensin; beef cattle; digestion; growth performance; high-concentrate diets; nitrogen-utilization; ruminal fermentation; rumen fermentation; continuous-culture; plant-extracts; dairy-cows; ionophores; efficiency; forage

SUMMARY: Two experiments were conducted with beef cattle to evaluate the effects of dietary addition of monensin (Rumensin (R) premix, MO) and different doses of a mixture of essential oils (Vertan (R); EO) on feed intake, growth performance and feed efficiency (exp. 1), nutrient digestibility and N retention (exp. 2). In exp. 1, 20 steers and 20 heifers (Angus x Hereford, initial BW = 369 +/- 10 kg) used in a random block design were fed a total mixed ration (TMR) without supplementation (control, CO), or supplemented with MO (33 mg kg DM-1) or EO (2 and 4 g/d). In exp. 2, five steers (Angus x Hereford, initial BW = 244 +/- 4 kg) used in a 5 x 5 Latin square design were fed CO, MO (33 mg kg DM-1), or EO (2, 3, and 4 g/d). In exp. 1, DM intake was not affected (P > 0.05) by the addition of EO, but it was 10% lower (P < 0.01) for cattle fed MO compared with those fed CO. Average daily gain (ADG) was similar (P > 0.05) between cattle fed CO and those fed MO or EO. Feed efficiency (ADG to DM intake ratio) was not affected (P > 0.05) by the addition of EO and MO in the diet, but EO had a quadratic effect (P < 0.05) being highest at the dose of 2 g of EO/d. In exp. 2, DM intake was similar (P > 0.05) for cattle fed MO and those fed CO, but it was higher for steers fed EO compared with those fed CO (6.30 vs. 5.85 kg d(-1); P < 0.05), and linearly increased (P < 0.05) with increased doses of EO. Neither the apparent digestibility nor the retention of N was affected (P > 0.05) by MO or EO addition. Results from this study suggest that EO have the potential to improve feed efficiency in beef cattle. EO are effective at lower dose levels but at higher dosage, EO appear to have no beneficial effect on feed efficiency.
(30-Nov-2006)
 

Kebreab E, Clark K, Wagner-Riddle C, France J (2006) Methane and nitrous oxide emissions from Canadian animal agriculture: A review Canadian Journal of Animal Science 86 (2): 135-158

KEYWORDS: greenhouse gases; enteric methane; nitrous oxide; manure management; greenhouse-gas emissions; liquid swine manure; mass-balance method; solid dairy manure; beef-cattle; pig manure; grazed pastures; grazing animals; carbon-dioxide; forage/concentrate ratio

SUMMARY: Considerable evidence of climate change associated with emissions of greenhouse gases (GHG) has resulted in international efforts to reduce GHG emissions. The agriculture sector contributes about 8% of GHG emissions in Canada mostly through methane (CH4) and nitrous oxide (N2O). The objective of this paper was to compile an integrative review of CH4 and N2O emissions from livestock by taking a whole cycle approach from enteric fermentation to manure treatment and storage, and field application of manure. Basic microbial processes that result in CH4 production in the rumen and hindgut of animals were reviewed. An overview of CH4 and N2O production processes in manure, and controlling factors are presented. Most of the studies conducted in relation to enteric fermentation were in dairy and beef cattle. To date, research has focussed on GHG emissions from the stored manures of dairy, beef cattle and swine; therefore, we focus our review on these. Several methods used to measure GHG emissions from livestock and stored manure were reviewed. A comparison of methods showed that there were agreements between most of the techniques but some systematic differences were also observed. Additional studies with comprehensive comparisons of methodologies are needed in order to allow for comparison of results obtained from studies using contrasting methodologies. The need to standardize measurement methods and reporting to facilitate comparison of results and data integration was identified. Prediction equations are often used to calculate GHG emissions. Various types of mathematical approaches, such as statistical models, mechanistic models and estimates calculated from emission factors, and studies that compare various types of models are discussed herein. A lack of process-based models describing GHG emissions from manure during storage was identified. A brief description of mitigation strategies focussing on recent studies is given. Reduction in CH4 emissions from ruminants through the addition of fats in diets and the use of more starch was achieved and a transient beneficial effect of ionophores was reported. Grazing management and genetic selection also hold promise. Studies focussed on manure treatment options that have been suggested to reduce gas fluxes from manure storage, composting, anaerobic digestion (AD), diet manipulation, covers and solid-liquid separation, were reviewed. While some of these options have been shown to decrease GHG emissions from stored manure, different studies have obtained conflicting results, and additional research is needed to identify the most promising options. GHG emissions from pasture and croplands after manure application have been the subject of several experimental and modelling studies, but few of these have linked field emissions to diet manipulation or manure treatments. Further work focussing on the entire cycle of GHG formation from feed formulation, animal metabolism, excreta treatment and storage, to field application of manure needs to be conducted.
(30-Nov-2006)
 

Martinez S, Madrid J, Hernandez F, Megias MD, Sotomayor JA, Jordan MJ (2006) Effect of thyme essential oils (Thymus hyemalis and Thymus zygis) and monensin on in vitro ruminal degradation and volatile fatty acid production Journal of Agricultural and Food Chemistry 54 (18): 6598-6602

KEYWORDS: in vitro degradability; monensin; Thymus hyemalis; Thymus zygis; essential oils; protein degradability; antibacterial properties; rumen fermentation; bacillus-cereus; beef-cattle; supplementation; carvacrol; blend; diets

SUMMARY: The effect of the essential oils of thyme on the in vitro ruminal degradability of a barley seed/alfalfa hay substrate was studied. Two essential oils were used, one from Thymus hyemalis (TH), rich in carvacrol, and the other from Thymus zygis (TZ), rich in thymol. Four experimental treatments of in vitro degradability, using the Daisy II200/220 incubator, were conducted including a negative control (CO), g/mL of monensin (MO), and two treatments withma positive control at 7.5  L/mL. The material was incubated at 39.5messential oils (TH or TZ) at 1.35  degrees C for various lengths of time. At each time, the disappearance of dry matter, crude protein, and neutral detergent fiber was measured. Volatile fatty acids (VFAs) were determined after 48 h of incubation. CO and MO provided (p < 0.01) higher values of potential degradability (a + b) of DM than the TH and TZ treatments (72.6 and 70.8 vs 53.2 and 48.2%, respectively). Also, crude protein degradability was lowest in the essential oil treatments. The CO treatment showed the highest potential degradability of NDF. The values of VFA production obtained (p < 0.001) with CO and MO treatments were higher than those obtained with TH and TZ treatments (21.0 and 19.1 vs 11.2 and 10.1 mM). The essential oils decreased the molar proportion of propionate, increasing the acetate/propionate ratio. In conclusion, the effects of essential oils at assayed doses would not be nutritionally beneficial to the ruminal energetic metabolism.
(30-Nov-2006)
 

Martins AD, Vieira PD, Berchielli TT, do Prado IN, Garcia JAS (2006) Microbial synthesis efficiency and enzyme activity in cattle supplemented with fibrolytic enzymes Revista Brasileira de Zootecnia-Brazilian Journal of Animal Science 35 (3): 1194-1200 Suppl. S (in Portuguese)

KEYWORDS: cellulase; corn silage; ruminants; Tifton hay; dairy-cows; digestive characteristics; nutrient digestion; protein-synthesis; beef steers; in-vitro; forage; fermentation; digestibility; degradability

SUMMARY: It was investigated the effects of fibrolytic enzymes (cellulase and xylanase) on the microbial protein synthesis efficiency and enzymatic activity of beta-1,4-endoglucanase (cellulase) in animals receiving diets with corn silage and Tifton 85 hay (Cynodon spp.). Eight bovines fitted with rumen and duodenum cannulas were randomly assigned to two replicated 4 x 4 Latin squares with a 2 x 2 factorial arrangement of treatments (two forage sources with or without fibrolytic enzymes). The commercial enzymatic complex used in this trial was extracted from Aspergillus niger and Trichoderma longibrachiatum fungi. Each animal received 12 g/day of the enzymatic complex by mixing it in the ration. Inclusion of fibrolytic enzymes in the diet increased the beta-1,4-endoglucanase activity in the ruminal fluid of animals fed both forages. However, there was no effect of enzymes on efficiency of microbial protein synthesis that averaged 31.8 and 33.9 g of N/kg of OMDR and 0.40 and 0.41 g of N/Mcal of EDR, respectively, for corn silage and Tifton hay diets. Similarly, duodenal flows of microbial nitrogen (mic-N) and non ammonia nitrogen (NAN) did not differ and averaged 78.2 and 52.5 g/day and 89.6 and 76.3 g/day for corn silage and Tifton hay, respectively. Supplementation with fibrolytic enzymes had no effect on the ruminal parameters of cattle fed hay or corn silage.
(30-Nov-2006)
 

Jordan E, Kenny D, Hawkins M, Malone R, Lovett DK, O'Mara FP (2006) Effect of refined soy oil or whole soybeans on intake, methane output, and performance of young bulls Journal of Animal Science 84 (9): 2418-2425

KEYWORDS: beef bull; enteric methane; high concentrate diet; soy oil; whole soybean; coconut oil; meat quality; rumen; sheep; digestion; carcass; silage; oilseeds; release; growth

SUMMARY: An experiment was conducted to establish the effects of feeding refined soy oil (RSO) or whole soybeans (WSB) containing soy oil on DMI, animal performance, and enteric methane (CH4) emissions in young bulls. Thirty-six Charolais and Limousin crossbred, young beef bulls (338 27 kg of BW, 218 +/- 17 d of age at the beginning of the experiment) were blocked by BW, age, and breed before being assigned in a randomized complete block design to 1 of 3 experimental treatments (n = 12). The experimental period lasted for 103 d, with enteric CH4 output recorded for 2 periods of 5 consecutive days on d 37 to 41 and d 79 to 83. The 3 dietary treatments consisted of a barley/soybean meal-based concentrate with 0 g/d of RSO; oil from WSB as 6% of DMI (WSB treatment); and oil from RSO as 6% of DMI (RSO treatment). Each diet had a 10:90 forage: concentrate ratio, using barley straw as the forage source. Diet affected DMI (P <= 0.001) and GE intake (P < 0.05 during the CH4 measurement periods), with the WSB treatment producing the lowest values. The addition of WSB decreased ADG (P < 0.05) compared with the RSO treatment. The WSB treatment also decreased (P < 0.05) average daily carcass gain (ADCG). Both the RSO and WSB concentrates decreased (P < 0.05 to P < 0.001) daily enteric CH4 output when expressed in terms of liters per day, liters per kilogram of DMI, percentage of GE intake, liters per kilogram of ADG, and liters per kilogram of ADCG. Diet had no effect (P = 0.557) on ruminal protozoal numbers. The reductions in enteric CH4 were achieved at relatively high oil inclusion levels. Such oil levels have previously been reported to decrease DMI of high-forage diets, although no effect on DMI was noted with the low-forage diets fed in this experiment. This impact on DMI of high-forage diets may limit the range of diets for which this CH4 reduction strategy may be applicable. The inclusion level of WSB in the current experiment (27%) was beyond the palatability threshold of the bulls used and resulted in a marked decline in intake and performance. Therefore, WSB may have a role to play in ruminant diets, but only at a reduced inclusion rate.
(30-Nov-2006)
 

Koppova I, Lukas F, Kopecny J (2006) Effect of fatty acids on growth of conjugated-linoleic-acids-producing bacteria in rumen Folia Microbiologica 51 (4): 291-293

KEYWORDS: Butyrivibrio-Fibrisolvens; biohydrogenation; cows

SUMMARY: Microorganisms with high activity of linoleic acid Delta 12-cis, Delta 11-trans-isomerase were isolated from the digestive tract of ruminants and characterized. The isolate with the highest isomerase activity was identified as Pseudobutyrivibrio ruminis. The susceptibility of this strain to 3 fatty acids added to the grow medium was determined. A significant inhibition of bacterial growth (during a 3-d period) by linoleic acid (0.1%) and oleic acid (5 ppm) was observed; no inhibition was found in the presence of stearic acid.
(30-Nov-2006)

Gulati SK, McGrath S, Wynn PC, Thomson PC, Scott TW (2006) Rumen protected fat reverses the conjugated linoleic acid induced low milk fat content in dairy cows Canadian Journal of Animal Science 86 (1): 63-70

KEYWORDS: rumen protected conjugated linoleic acid; rumen protected fat supplements; milk; fat; fatty acids; abomasal infusion; delta(9)-desaturase; hydrogenation; yield; CLA

SUMMARY: Conjugated linoleic acids (CLAs) were protected by encapsulation in a matrix of formaldehyde-treated protein; these rumen protected (RP-CLAs) were fed in two separate trials using Holstein cows grazing pasture to examine their effects on milk fat content, yield and fatty acid composition. In trial 1, three groups of nine cows were fed pasture alone, RP-CLA (61.5 g/d equivalent to 10.3 g of trans-10, cis-12 isomer) and rumen protected canola/soybean (RP-C/SB) (65.6 g/d to have the equivalent level of fat containing no CLA). RP-CLA reduced milk fat yield by 27, 29 and by 38%, respectively, after 4, 7 and 10 d of supplementation. Milk fat content was also reduced and after 10 d of CLA supplementation declined from 3.7 to 2.3%. RP-CLA supplementation resulted in a gradual decline in the yield of C-10-C-14, C-16 and C-18, fatty acids in milk during the 10-d feeding period. In trial 2, feeding RP-CLA for 4 d reduced milk fat content (pasture 3.4%, RP-CLA 2.4%) and yield (pasture 826 g/d), RP-CLA 594 g/d) by the same magnitude of 29%. Milk fat content and yield was restored by feeding RP-CLA together with RP-C/SB supplement (1-2 kg /d), which provided an additional 328 g or 656 g of fat per day; this suggests that CLA preferentially inhibits mammary gland lipogenesis.
(30-Nov-2006)
 

Rodriguez CA, Gonzalez J (2006) In situ study of the relevance of bacterial adherence to feed particles for the contamination and accuracy of rumen degradability estimates for feeds of vegetable origin British Journal of Nutrition 96 (2): 316-325

KEYWORDS: rumen; microbial contamination; effective degradability; N-15/N; sheep; amino-acid-composition; protein degradability; intestinal digestibility; microbial-contamination; nitrogen degradability; chemical-composition; solid fractions; dry-matter; digestion; incubation

SUMMARY: An in situ study was conducted on four rumen-cannulated wethers to determine (using N-15 infusion techniques) the microbial contamination (mg bacterial DM or crude protein (CP)/100 mg DM or CP) and the associated error on the effective degradability of fourteen feeds: barley and maize grains, soyabean and sunflower meals, full-fat soyabean, maize gluten feed, soyabean hulls, brewers dried grains, sugarbeet pulp, wheat bran, lucerne and vetch-oat hays, and barley and lentil straws. The DM or CP contamination in residues (M) fitted to single exponential or sigmoid curves. A general model (M=m (1-e(-ft) ) (j)) was proposed to match this fit. Asymptotic values (m) varied from 2.84 % to 13.3 % and from 2. 85 % to 80.9 % for DM and CP, respectively. Uncorrected results underestimated the effective degradability of both DM (P < 0.05) and CP (P < 0.01). For CP, this underestimation varied from 0.59 % to 13.1 %, with a higher but unascertainable error for barley straw. Excluding maize grain, the microbial contamination of both DM and CP, and the associated underestimation of the effective degradability of CP, were positively related to the cellulose content of the feed. The error in the effective degradability of CP was also negatively related to the CP content and its apparent effective degradability (R2 = 0.867). This equation allows easier and more accurate estimates of effective degradability, needed to improve protein-rationing systems.
(30-Nov-2006)
 

Li YL, Meng QX (2006) Effect of different types of fibre supplemented with sunflower oil on ruminal fermentation and production of conjugated linoleic acids in vitro Archives Of Animal Nutrition 60 (5): 402-411

KEYWORDS: conjugated linoleic acids; fibre type; ruminal fermentation in vitro; unsaturated fatty-acids; dairy-cows; milk-fat; anticarcinogenic agents; duodenal flow; bovine-milk; biohydrogenation; rumen; invitro; forage

SUMMARY: An in vitro study was conducted to determine the effect of different types of fibre supplemented with sunflower oil on ruminal fermentation and formation of conjugated linoleic acids (CLA) by mixed ruminal microorganisms. Cell wall components extracted from wheat straw (representing lignified fibre), soybean hulls (representing easily digestible fibre), and purified cellulose were used as substrates. Sunflower oil was supplemented at the same level for all three types of fibre. After 24 h of incubation, ruminal fermentation parameters (including 24 h gas production, pH value, concentration of ammonia nitrogen and volatile fatty acids) and the concentration of long chain fatty acids in the culture fluid were determined. Results showed that the type of fibre influenced ruminal fermentation traits and the biohydrogenation of unsaturated C18 fatty acids in vitro. Composition of LCFA and profile of CLA were altered by the fibre type. Compared to the digestible fibre and purified cellulose, lignified fibre significantly increased the production of cis-9, trans-11 CLA and total CLA (sum of cis-9, trans-11 CLA, trans-10, cis-12 CLA, trans-9, trans-11 CLA, and cis-9, cis-11 CLA) by ruminal microorganisms. It was concluded that ruminal fermentation and production of CLA can be affected by the type of dietary fibre.
(30-Nov-2006)
 

Pen B, Sar C, Mwenya B, Kuwaki K, Morikawa R, Takahashi J (2006) Effects of Yucca schidigera and Quillaja saponaria extracts on in vitro ruminal fermentation and methane emission Animal Feed Science and Technology 129 (3-4): 175-186

KEYWORDS: Yucca schidigera; Quillaja saponaria; ruminal fermentation; methane; rumen fermentation; methanogenesis; concentrate; saponins; protozoa; diets; microorganisms; degradation; sarsaponin; metabolism

SUMMARY: An in vitro continuous incubation system was used to evaluate effects of increasing concentrations of Yucca schidigera extract (YSE) and Quillaja suponaria extract (QSE), at 0, 2, 4, and 6 ml/l, on rumen fermentation and methane production. The culture media consisted of 400 ml of strained rumen fluid collected from two ruminally cannulated non-lactating Holstein cows fed oat and alfalfa hay (1: 1, w/w) at a maintenance energy level (i.e., 55 g of DM/kg of BW 0.75 daily), and 400 ml of McDougall's buffer. Treatments were in two 4 x 4 Latin square experiments for YSE and QSE. The culture media were anaerobically incubated with 10 g of a mixture of ground concentrate and oat hay (1: 1, w/w) at 39 degrees C for 24 h. Gas emission from each fermentation vessel was measured continuously by infrared methane and carbon dioxide gas analyzers. Rate and extent of methane production were reduced (P < 0.001) by YSE addition in a dose-dependent manner by up to 42% and up to 32%, respectively, whereas QSE did not effect methane production. Medium pH was not altered by YSE, but increased (P < 0.01) with QSE addition. Ammonia N concentrations were markedly reduced (P < 0.001) by YSE in a dose-dependent manner by up to 48%, whereas QSE supplementation only tended (P=0.06) to decrease NH3-N concentrations. Protozoal numbers decreased (P < 0.001) by up to 56% with YSE and by up to 41% with QSE addition. Addition of YSE and QSE increased (P < 0.001) medium optical density at 660 nm (OD660), indicating that microbial populations increased. Propionate concentration increased (P < 0.001) by up to 54% and acetate to propionate ratios decreased (P < 0.001) by YSE addition in dose-dependent manners. QSE addition increased (P < 0.05) propionate concentrations by up to 19%, but there were no differences among levels of QSE addition. Results suggest that Y. schidigera extract has a particular suppressing effect on rumen methanogenesis and that both plant extracts, Y. schidigera and Q. saponaria, may have potential as antiprotozoal agents.
(30-Nov-2006)
 

Cox RB, Kerth CR, Gentry JG, Prevatt JW, Braden KW, Jones WR (2006) Determining acceptance of domestic forage- or grain-finished beef by consumers from three southeastern US states Journal of Food Science 71 (7): S542-S546

KEYWORDS: beef; collagen; consumer; forage; tenderness; palatability characteristics; carcass characteristics; steers; grass; quality; pasture; meat; concentrate; collagen; tenderness

SUMMARY: Twenty-six crossbred steers were finished either on ryegrass(Lolium multiflorum Lam.) forage (FOR, n=13) or a primarily gain diet containing 85% corn, 7.5% cotton-seed hulls, and 7.5% vitamin/mineral/urea supplement (GRAIN, n = 13) to determine the consumer acceptance of forage- and grain-finished beef in 3 southeastern states. Shear force values were not affected by finishing-treatment (P=0.62), and both, total and heat-labile collagen content means of the FOR and GRAIN steaks were similar (P=0.88 and 0.14, respectivly). Ribeye steaks were cut from wholesale roasts after 14d of aging and were evaluated by 1250 consumers in a retail study and 87 consumers in a take-home study across Alabama, Tennessee, and Kentucky. Retail consumers rated GRAIN steaks higher for flavor (P=0.001), overall palatability (P=0.001) and price per kg (P=0.001) compared to FOR steaks, but consumers in the take-home study found no differences in any of the 3 traits. Consumers-that preferred FOR steaks were willing to pay an average of $2.38kg and $5.61/kg more for FOR steaks than for GRAIN, steaks in the retail and take-home, studies, respectively (P=0.001), Among consumers survayed across all 3 states, 34.1% of retail consumers and 54.0% of take-home consumers preferred FOR steaks. At least one-third of the consumers surveyed preferred the taste of forage-finished beef and were willing to pay a premium.
(30-Nov-2006)
 

Purchas RW, Busboom JR, Wilkinson BHP (2006) Changes in the forms of iron and in concentrations of taurine, carnosine, coenzyme Q(10), and creatine in beef longissimus muscle with cooking and simulated stomach and duodenal digestion Meat Science 74 (3): 443-449
KEYWORDS: pepsin digestion; pancreatin; bile extract; haem iron; beef; cooking; heme-iron; meat; lamb; protein

SUMMARY: Longissimus muscle samples from 31 Angus-cross heifers finished on either a high-concentrate feedlot diet or pasture were used to evaluate the effects of cooking (71 degrees C) on the concentration and forms of iron in the meat, and also on concentrations of the bioactive compounds taurine, carnosine, coenzyme Q(10), creatine and creatinine. For a sub-sample of 15 the effects of pepsin and pancreatin digestion were assessed. For iron, cooking resulted in some overall loss together with a major change from soluble haem and non-haem iron to the insoluble forms, but solubility was regained to a significant extent following digestion. Total haem iron percentage, however, decreased at each step from an initial 88% to a final 61% of total iron. For the bioactive compounds, cooking led to a reduction in taurine, carnosine, coenzyme Q(10), and creatine. The effects of digestion on the bioactive compounds varied. No clear differences were shown in the way in which beef from pasture-finished and feedlot-finished cattle responded to cooking and digestion.
(30-Nov-2006)
 

Kawachi H (2006) Micronutrients affecting adipogenesis in beef cattle Animal Science Journal 77 (5): 463-471

KEYWORDS: adipocyte; cattle; marbling; mineral; vitamin; adipocyte differentiation; carcass characteristics; insulin-receptor; dietary calcium; adipose-tissue; preadipocyte differentiation; supplemental chromium; tyrosine kinase; vitamin-a; steers

SUMMARY: Beef marbling is an important trait of meat quality and beef marbling influences the tenderness and flavor of beef, which contributes directly to the value of beef especially in the Japanese market. The lipid content of beef depends on the strain, sex, diet and fattening period of the animal. Japanese Black cattle (Wagyu) are well-known for their ability to produce marbling beef and this is a popular strain in Japan. The development of beef marbling was closely associated with an increase in the number of adipocytes, that is, adipocyte differentiation in the skeletal muscle. This review article describes our experiment and related reports on micronutrients, especially vitamins and minerals, affecting adipogenesis in beef cattle. We pursue the possibility that manipulating the level of dietary micronutrients may become a new technique to promote beef marbling.
(30-Nov-2006)
 

Hansen S, Therkildsen M, Byrne DV (2006) Effects of a compensatory growth strategy on sensory and physical properties of meat from young bulls Meat Science 74 (4): 628-643

KEYWORDS: sensory tenderness; compensatory growth; Ad libitum feeding; young bulls; Longissimus dorsi; Semimembranosus; Supraspinatus; muscle-fiber characteristics; warmed-over flavor; major beef muscles; feeding intensity; eating quality; tenderness; cattle; steers; semitendinosus; palatability

SUMMARY: The objective of the present study was to investigate the sensory properties, with special emphasis on tenderness, of meat from strategically fed young bulls (13 months of age) slaughtered when a plateau in protein turnover was observed. Twelve Holstein Friesian young bulls were divided into two feeding strategies. One group of young bulls (n = 6) were fed ad libitum throughout the rearing period (AD) whereas the second group (n = 6) was subjected to a compensatory growth feeding strategy (CO). Sensory profiling of beef longissimus dorsi (LD), semimembranosus (SM) and supraspinatus (SS) was performed in addition to physical measurements (shear force) and content of intramuscular fat of LD. The data was analysed using a regression-based multivariate data analytical strategy. In relation to predictivity of the various shear force measurement constituents for sensory texture, it was determined that a number of the responses collected (e.g. max(mm)), in addition to the commonly used max((N)) may be utilised to predict subtlety in the sensory texture differences of the samples (e.g. Crumbliness) with respect to compensatory feeding. Through profiling LD and SS were found to have enhanced texture and flavour properties when the young bulls were fed ad libitum during rearing. However, the SM samples were found to improve in characteristics regarding texture and appearance when the young bulls had been fed compensatorily. Thus, compensatory feeding as a texture improvement strategy proved to be highly dependant on muscle type. Of note, LD and SS were found to develop an off-flavour designated as 'steer taint' when derived from compensatory feeding. This was postulated as potentially not a problem for the consumer, in LD as the level was not significant, and in SS due to sensory masking when commonly prepared as a stew or casserole. Considering the different preparation methods used for meat from LD, SM and SS, compensatory feeding may be considered to have improved the texture and elevated the eating quality where it was most relevant, namely in SM roasts.
(30-Nov-2006)
 

Cardozo PW, Calsamiglia S, Ferret A, Kamel C (2006) Effects of alfalfa extract, anise, capsicum, and a mixture of cinnamaldehyde and eugenol on ruminal fermentation and protein degradation in beef heifers fed a high-concentrate diet Journal of Animal Science 84 (10): 2801-2808
KEYWORDS: plant extract; rumen fermentation; rumen microbial fermentation; simulation technique rusitec; continuous-culture system; essential oil compounds; natural plant-extracts; yucca-schidigera; microorganism fermentation; digestive function; milk-production; malic-acid

SUMMARY: Four Holstein heifers (360 22 and 450 28 kg of BW in Exp. 1 and 2, respectively) fitted with ruminal trocars were used in 4 x 4 Latin square designs to evaluate the effects on ruminal microbial fermentation of the following: Exp. 1, no additive, alfalfa extract (30 g/d, AEX), a mixture of cinnamaldehyde (0.18 g/d) and eugenol (0.09 g/d; CIE1), and AEX and CIE1 in combination; and Exp. 2, no additive, anise oil (2 g/d), capsicum oil (1 g/d), and a mixture of cinnamaldehyde (0.6 g/d) and eugenol (0.3 g/d). Heifers were fed a 90:10 concentrate:barley straw diet (16% CP; 25% NDF) for ad libitum intake. Each period consisted of 15 d for adaptation and 6 d for sampling. On d 16 to 18, DM and water intakes were measured. On d 19 to 21 ruminal contents were sampled at 0, 3, 6, 9, and 12 h after feeding to determine ruminal pH and the concentrations of VFA, L-lactate, large peptides, small peptides plus AA (SPep+AA), and ammonia N. On d 20 and 21, samples of ruminal fluid were collected at 0 and 3 h after feeding to determine protozoal counts. In Exp. 1, CIE1 and AEX decreased (P < 0.05) total DMI, concentrate DMI, and water intake. The increase (P < 0.05) in SPep+AA and the decrease (P < 0.05) in ammonia N when supplementing CIE1 suggest that deamination was inhibited. Treatment AEX increased (P < 0.05) the acetate to propionate ratio, which is less efficient for beef production. Treatment CIE1 increased (P < 0.05) counts of holotrichs. Effects of AEX and CIE1 were not additive for many of the measured metabolites. In Exp. 2, treatments had no effect on ruminal pH, total VFA concentration, and butyrate proportion. The capsicum oil treatment increased (P < 0.05) DMI, water intake, and SPep+AA N concentration and decreased (P < 0.05) acetate proportion, branched-chain VFA concentration, and large peptide N concentration. The cinnamaldehyde (0.6 g/d) and eugenol (0.3 g/d) treatment decreased (P < 0.05) water intake, acetate proportion, branched-chain VFA, L-lactate, and ammonia N concentrations and increased (P < 0.05) propionate proportion and SPep+AA N concentration. The anise oil treatment decreased (P < 0.05) acetate to propionate ratio, branched-chain VFA and ammonia N concentrations, and protozoal counts. The results indicate that at the doses used a mixture of cinnamaldehyde and eugenol, anise oil, and capsicum oil may be useful as modifiers of rumen fermentation in beef production systems.
(30-Nov-2006)
 

Tracy BF, Faulkner DB (2006) Pasture and cattle responses in rotationally stocked grazing systems sown with differing levels of species richness Crop Science 46 (5): 2062-2068

KEYWORDS: botanical composition; ecosystem function; varied diets; tall fescue; productivity; biodiversity; forage; performance; diversity; grasslands

SUMMARY: Increasing species richness of temperate pastures beyond one or two forage species could improve grazing system productivity. An experiment in western Illinois, USA, was initiated in August 2001 to test this idea. The main study objective was to determine how pastures sown with increasing levels of species richness would affect herbage yield and cow-calf performance. Three seed mixtures that contained three, five, or eight forage species were sown into 3- to 6-ha pastures. Mixtures were replicated three times and rotationally stocked with beef cow-calf groups. Herbage mass and accumulation were estimated by a rising plate meter method and weight gain evaluated cow-calf performance. We also evaluated forage nutritive value indices and changes in forage species composition. After pasture establishment in 2001, herbage mass was marginally higher (P = 0.15) in eight-species mixtures (98 g m(-2)) compared with three-species mixes (43 g m(-2)). Once grazing started, pasture mix had no effect on herbage responses or stocking rate (P > 0.05). Cow-calf performance was also unaffected by pasture mix, although average daily gain (ADG) was higher in 2003 (P < 0.05). Cow and calf ADG averaged 0.33 and 1.17 kg d(-1), respectively, in 2003 compared with 0.05 and 1.01 kg d(-1) in other years. Overall, species richness in pastures had minimal effects on forage yield and cattle performance. Grazing management (e.g., stocking rate) and climatic conditions more strongly influence grazing system productivity.
(30-Nov-2006)
 

Benchaar C, Petit HV, Berthiaume R, Whyte TD, Chouinard PY (2006) Effects of addition of essential oils and monensin premix on digestion, ruminal fermentation, milk production, and milk composition in dairy cows Journal of Dairy Science 89 (11): 4352-4364

KEYWORDS: essential oil; monensin; metabolism; dairy cow; rumen microbial fermentation; controlled-release capsule; fatty-acid content; protein degradability; nitrogen-utilization; concentrate ratios; continuous-culture; plant-extracts; diets; forage

SUMMARY: Four ruminally cannulated, lactating Holstein cows were used in a 4 x 4 Latin square design (28-d periods) with a 2 x 2 factorial arrangement of treatments to study the effects of dietary addition of essential oils (0 vs. 2 g/d; EO) and monensin (0 vs. 350 mg/d; MO) on digestion, ruminal fermentation characteristics, milk production, and milk composition. Intake of dry matter averaged 22.7 kg/d and was not significantly affected by dietary additives. Apparent digestibilities of dry matter, organic matter, neutral detergent fiber, and starch were similar among treatments. Apparent digestibility of acid detergent fiber was increased when diets were supplemented with EO (48.9 vs. 46.0%). Apparent digestibility of crude protein was higher for cows fed MO compared with those fed no MO(65.0 vs. 63.6%). Nitrogen retention was not changed by additive treatments and averaged 27.1 g/d across treatments. Ruminal pH was increased with the addition of EO (6.50 vs. 6.39). Ruminal ammonia nitrogen (NH3- N) concentration was lower with MO-supplemented diets compared with diets without MO (12.7 vs. 14.3 mg/100 mL). No effect of EO and MO was observed on total volatile fatty acid concentrations and molar proportions of individual volatile fatty acids. Protozoa counts were not affected by EO and MO addition. Production of milk and 4% fat-corrected milk was similar among treatments (33.6 and 33.4 kg/d, respectively). Milk fat content was lower for cows fed MO than for cows fed diets without MO (3.8 vs. 4.1%). The reduced milk fat concentration in cows fed MO was associated with a higher level of trans-10 18:1, a potent inhibitor of milk fat synthesis. Milk urea nitrogen concentration was increased by MO supplementation, but this effect was not apparent when MO was fed in combination with EO (interaction EO x MO). Results from this study suggest that feeding EO (2 g/d) and MO (350 mg/d) to lactating dairy cows had limited effects on digestion, ruminal fermentation characteristics, milk production, and milk composition.
(30-Nov-2006)
 

Rulquin H, Graulet B, Delaby L, Robert JC (2006) Effect of different forms of methionine on lactational performance of dairy cows Journal of Dairy Science 89 (11): 4387-4394

KEYWORDS: rumen-protected methionine; bioavailability; milk protein; dairy cow; hydroxy analog; protected methionine; milk-production; isopropyl ester; rumen; acid; lysine; bioavailability; availability; degradation

SUMMARY: Methionine is one of the first limiting AA in dairy cows. The use of rumen-protected Met to correct deficient diets is limited by the lack of a product that could be incorporated into a pelleted concentrate. The main objective of this trial was to test, at practical doses (approximately 10 g of absorbable Met), the efficacy of 2 forms of pelletable Met hydroxy analogs, D, L-2-hydroxy- 4-(methylthio)-butanoic acid (HMB) and the isopropyl ester of HMB (HMBi), to provide Met to cows, especially for milk protein synthesis, compared with a negative control and to Smartamine M (SmM). These treatments were tested according to a 4 x 4 Latin square in 16 Holstein cows. Plasma Met concentrations were increased by 110 and 65% that of the control value after HMBi and SmM treatments, respectively. Milk protein yield increased by 32 and 41 g/d for HMBi and SmM, respectively. D, L-2-Hydroxy- 4-(methylthio)-butanoic acid supplementation did not improve Met availability to the cows for milk protein synthesis. The HMBi treatment induced an increase in 15:0 in milk at the expense of a general reduction in even-numbered shortand medium-chain fatty acids. Moreover, HMBi and SmM supplements led to an increase in the saturation level of C-18 fatty acids consistent with the improvement of Met supply. It was concluded that HMBi is a new "rumen-protected" form of Met that can be supplied to cows integrated into pellets.
(30-Nov-2006)
 

Shrestha R, Wegge P (2006) Determining the composition of herbivore diets in the trans-Himalayan rangelands: A comparison of field methods Rangeland Ecology & Management 59 (5): 512-518

KEYWORDS: bite-count; Bos grunniens; Capra hircus; fecal analysis; feeding site examination; food habits; Ovis aries; fecal analysis; botanical composition; microhistological analysis; microscopic analysis; esophageal-fistula; tibetan plateau; steer diets; dry-weight; deer diets; rumen

SUMMARY: In late summer, in a semi-arid mountain range in Nepal, we compared 3 field methods for determining the botanical composition of herbivore diets. Data were collected from the same animals belonging to I herd of domestic yak (Bos grunniens) and 2 herds of mixed smallstock, consisting of domestic goats (Capra hircus) and sheep (Ovis aries). Bite count, feeding site examination, and microhistological analysis of feces gave different estimates of forage categories and plant species in both animal groups. Because yaks grazed in other vegetation communities when not observed for bite-counts and feeding signs, the results from the latter methods could not be compared directly with that from fecal analysis. In smallstock, feeding site examination gave higher estimates of graminoids and lower estimates of shrubs than the other 2 methods, probably because all feeding signs on shrubs were not detected. Bite-counts and fecal analysis gave comparable results, except that forbs were underestimated by fecal analysis, presumably due to their more complete digestion. Owing to the difficulty in collecting samples that are representative of the entire grazing period and the problem of recording feeding signs correctly, both feeding site examination and bite-counts are unsuitable methods for studying the food habits of free ranging domestic and wild herbivores. Microhistological analysis of feces appears to be the most appropriate method, but correction factors are needed to adjust for differential digestion. The systematic use of photomicrographs improves the speed and accuracy of the fecal analysis.
(30-Nov-2006)
 

Kirat D, Masuoka J, Hayashi H, Iwano H, Yokota H, Taniyama H, Kato S (2006) Monocarboxylate transporter 1 (MCT1) plays a direct role in short-chain fatty acids absorption in caprine rumen Journal of Physiology-London 576 (2): 635-647

KEYWORDS: gastrointestinal-tract; ruminal epithelium; butyrate transport; concentrate diets; lactate; membrane; expression; metabolism; cells; pyruvate

SUMMARY: Despite the importance of short-chain fatty acids (SCFA) in maintaining the ruminant physiology, the mechanism of SCFA absorption is still not fully studied. The goal of this study was to elucidate the possible involvement of monocarboxylate transporter 1 (MCT1) in the mechanism of SCFA transport in the caprine rumen, and to delineate the precise cellular localization and the level of MCT1 protein along the entire caprine gastrointestinal tract. RT-PCR revealed the presence of mRNA encoding for MCT1 in all regions of the caprine gastrointestinal tract. Quantitative Western blot analysis showed that the level of MCT1 protein was in the order of rumen >= reticulum > omasum > caecum > proximal colon > distal colon > abomasum > small intestine. Immunohistochemistry and immunofluorescence confocal analyses revealed widespread immunoreactive positivities for MCT1 in the caprine stomach and large intestine. Amongst the stratified squamous epithelial cells of the forestomach, MCT1 was predominantly expressed on the cell boundaries of the stratum basale and stratum spinosum. Double-immunofluorescence confocal laser-scanning microscopy confirmed the co-localization of MCT1 with its ancillary protein, CD147 in the caprine gastrointestinal tract. In vivo and in vitro functional studies, under the influence of the MCT1 inhibitors, p-chloromercuribenzoate (pCMB) and p-chloromercuribenzoic acid (pCMBA), demonstrated significant inhibitory effect on acetate and propionate transport in the rumen. This study provides evidence, for the first time in ruminants, that MCT1 has a direct role in the transepithelial transport and efflux of the SCFA across the stratum spinosum and stratum basale of the forestomach toward the blood side.
(30-Nov-2006)
 

Devillard E, McIntosh FM, Newbold CJ, Wallace RJ (2006) Rumen ciliate protozoa contain high concentrations of conjugated linoleic acids and vaccenic acid, yet do not hydrogenate linoleic acid or desaturate stearic acid British Journal of Nutrition 96 (4): 697-704

KEYWORDS: biohydrogenation; rumen protozoa; conjugated linoleic acids; trans fatty acids; unsaturated fatty-acids; biohydrogenation; bacteria; sheep; defaunation; metabolism; sequestration; fermentation; lipids

SUMMARY: Conjugated linoleic acids (CLA) have been shown to improve human health. They are derived from the microbial conversion of dietary linoleic acid (cis-9,cis-12-18 : 2 (LA)) in the rumen. An investigation was undertaken to determine the role of ruminal ciliate protozoa v. bacteria in the formation of CLA and its precursor in animal tissues, vaccenic acid (trans-11-18 : 1 (VA)). Mixed protozoa from the sheep rumen contained at least two to three times more unsaturated fatty acids, including CLA and VA, than bacteria. Different species had different composition, with larger fibrolytic species such as Epidinium ecaudatum caudatum containing more than ten times more CLA and VA than some small species, including Entodinium nanellum. In incubations with ruminal microbial fractions (bacterial fraction (BAC), protozoal fraction (PRO)), LA metabolism was very similar in strained ruminal fluid (SRF) and in the BAC, while the PRO had LA-metabolising activity an order of magnitude lower. Using PCR-based methods, no genes homologous to fatty acid desaturase genes were found in cDNA libraries from ruminal protozoa. The absence of an alternative route of VA/CLA formation via desaturation of stearate was confirmed by incubations of SRF, BAC or PRO with [C-14] stearate. Thus, although protozoa are rich in CLA and VA, they appear to lack the ability to form these two fatty acids from LA or stearate. The most likely explanation is that protozoa preferentially incorporate CLA and VA formed by bacteria. The implication of the present findings is that the flow of unsaturated fatty acids, including CLA and VA, from the rumen could depend on the flow of protozoa rather than bacteria.
(30-Nov-2006)
 

Wina E, Muetzel S, Becker K (2006) Effects of daily and interval feeding of Sapindus rarak saponins on protozoa, rumen fermentation parameters and digestibility in sheep Asian-Australasian Journal of Animal Sciences 19 (11): 1580-1587

KEYWORDS: digestibility; interval feeding; rumen; saponin; Sapindus rarak; yucca-schidigera extract; tropical grass diet; ruminal fermentation; ciliate protozoa; in-vitro; saponaria fruits; nutrient digestion; methane production; alfalfa saponins; plant-extracts

SUMMARY: Several researchers have demonstrated that the rumen microbial community rapidly adapts to saponins and proposed interval feeding to prevent this rapid adaptation. An in vivo experiment was carried out to examine the effect of daily versus application every third day (interval feeding) of Sapindus rarak saponins (SE) on rumen fermentation end products, protozoal counts and nutrient digestibility. Thirty sheep were allocated into 5 groups. Sheep were fed daily or every third day with two levels of SE (0.48 and 0.72 g/kg body mass). One group received no saponin and served as control. All sheep received the same diet, a mixture of elephant grass and wheat pollard (65:35 w/w). Independent of the feeding regime and the level of inclusion, the addition of SE decreased protozoal counts and rumen ammonia concentrations (p < 0.01). Microbial N supply and N retention were not affected by the high feeding regime. Daily feeding negatively influenced rumen xylanase and cellulase activity, but only when the high level of saponins was fed. However, these negative effects on rumen cell wall degradation were not reflected in decreasing total tract digestibility of the organic matter or the plant cell walls. Our results show that rumen microorganisms do not rapidly adapt to S. rarak saponins.
(30-Nov-2006)
 

Watanabe K, Fredeen AH, Robinson PH, Chalupa W, Julien WE, Sato H, Suzuki H, Katoh K, Obara Y (2006) Effects of fat coated rumen bypass lysine and methionine on performance of dairy cows fed a diet deficient in lysine and methionine Animal Science Journal 77 (5): 495-502

KEYWORDS: lactating cows; milk protein; rumen protected amino acids; ruminally protected lysine; indigestible particles; postruminal protein; amino-acids; passage; requirements; responses; alfalfa; goats; sheep

SUMMARY: Two experiments were conducted to evaluate the effect of fat coated rumen bypass lysine (RPLys) and methionine (RPMet) on the lactation performance of dairy cows. In Experiment 1, three lactating cows were supplied with RPLys and fat coated DL-Met which was highly protected (H-RPMet) as an indigestible marker, and total fecal emission was collected for 72 h following administration. Measuring the proportional difference in fecal excretion of lysine derived from RPLys relative to methionine derived from H- RPMet, the intestinal availability of RPLys was estimated to be 66.2%. In Experiment 2, 20 multiparous Holstein cows producing approximately 40 kg/ day of milk were assigned to two treatments; fed RPLys (16 g/day as lysine) and RPMet (6.5 g/day as methionine) or none (control) from 5 to 21 weeks postpartum. The consumption of dry matter, organic matter, crude protein, neutral detergent fiber and acid detergent fiber were significantly more in the control cows throughout the experimental period. Their milk protein yield, the contents of their milk protein and milk fat were higher by 0.03 kg (P = 0.03), 0.06% (P < 0.001) and 0.11% (P = 0.07), respectively, in the treatment group compared to the control. These results suggest that the RPLys and RPMet used in this study improved the lactation performance of dairy cows.
(30-Nov-2006)
 

Reynolds CK (2006) Production and metabolic effects of site of starch digestion in dairy cattle Animal Feed Science and Technology 130 (1-2): 78-94

KEYWORDS: starch; dairy cattle; site of digestion; small-intestinal disappearance; portal-drained viscera; volatile fatty-acids; milk-yield; grass-silage; nitrogenous compounds; abomasal glucose; duodenal glucose; splanchnic metabolism; ruminal fermentation

SUMMARY: Milk solids yield in modern dairy cows has increased linearly over the last 50 years, stressing the need for maximal dietary energy intake to allow genetic potential for milk energy yield to be realized with minimal negative effects on health and reproduction. Feeding supplemental starch is a common approach for increasing the energy density of the ration and supplying carbon for meeting the substantial glucose requirement of the higher yielding cow. In this regard, it is a long held belief that feeding starch in forms that increase digestion in the small intestine and glucose absorption will benefit the cow in terms of energetic efficiency and production response, but data supporting this dogma are equivocal. This review will consider the impact of supplemental starch and site of starch digestion on metabolic and production responses of lactating dairy cows, including effects on feed intake, milk yield and composition, nutrient partitioning, the capacity of the small intestine for starch digestion, and nutrient absorption and metabolism by the splanchnic tissues (the portal-drained viscera and liver). Whilst there appears to be considerable capacity for starch digestion and glucose absorption in the lactating dairy cow, numerous strategic studies implementing postruminal starch or glucose infusions have observed increases in milk yield, but decreased milk fat concentration such that there is little effect on milk energy yield, even in early lactation. Measurements of energy balance confirm that the majority of the supplemental energy arising from postruminal starch digestion is used with high efficiency to support body adipose and protein retention, even in early lactation. These responses may be mediated by changes in insulin status, and be beneficial to the cow in terms of reproductive success and well-being. However, shifting starch digestion from the rumen impacts the nitrogen economy of the cow as well by shifting the microbial protein gained from starch digestion from potentially absorbable protein to endogenous faecal loss.
(30-Nov-2006)
 

Huhtanen P, Sveinbjornsson J (2006) Evaluation of methods for estimating starch digestibility and digestion kinetics in ruminants Animal Feed Science and Technology 130 (1-2): 95-113

KEYWORDS: ruminant; starch; digestibility; digestion kinetics; lactating dairy-cows; gas-production; rumen fluid; fermentation kinetics; chemical-composition; nutrient digestion; corn grain; protein; degradation; invitro

SUMMARY: The objective of the paper is to review literature concerning the methods used to estimate starch digestibility in different segments of the digestive tract of ruminants and the kinetics of starch digestion. Starch digestibility and site of starch digestion have a profound effect on the amount and profile of substrates absorbed from the digestive tract. The prediction of starch digestibility in the rumen is laborious and also technically difficult because of unrepresentative sampling of digesta from duodenal cannulae. The double-marker technique does not solve the problems related to unrepresentative digesta sampling because any of the particulate markers are not intimately associated with particles rich in starch. Furthermore, physical separation of particles rich in starch and fibre, which is a requisite in applying multiple marker techniques, would be difficult. However, despite problems in the determination of starch flow, the double-marker technique is likely to improve the accuracy of the flow measurements of other components. Mechanistic dynamic models describing digestion and absorption of substrates require reliable estimates of the digestion kinetics of feed components. The in situ technique has been extensively evaluated and used in estimating the digestion rate of starch. Initial particle loss, often described as soluble starch, is the major problem of the technique. Various assumptions have been used for the behaviour of this fraction in the kinetic models. It is also possible that the secondary particle loss during the incubation would overestimate the rate of digestion. Both the patterns of duodenal marker excretion curves and duodenal starch flow strongly suggest that the passage of particles rich in starch do not follow the first-order passage kinetics. This means that the models used to estimate ruminal starch digestibility from the kinetic parameters are incomplete. The published data suggest that the in situ technique underestimates ruminal starch digestibility for slowly degradable starch sources such as maize and overestimates it for rapidly degradable starch sources such as barley. An advantage of the in vitro methods is that the estimates of starch disappearance are not biased by particle loss. In vitro gas production technique may also be used for estimation of the rate of starch digestion for cereal grains by applying the curve subtraction method; i.e. gas production from the cell wall fraction is subtracted from the total gas production curve. Starch represents the major proportion of cell solubles in cereal grains and even a greater proportion of gas production potential. A requisite of the in vitro techniques in estimating the rate of starch digestion is that the system itself is not limiting.
(30-Nov-2006)
 

Agarwal N, Kamra DN, Chaudhary LC, Patra AK (2006) Effect of Sapindus mukorossi extracts on in vitro methanogenesis and fermentation characteristics in buffalo rumen liquor Journal of Applied Animal Research 30 (1): 1-4

KEYWORDS: Sapindus mukurossi; soap nut; methanogenesis; buffalo; fermentation; plant-extracts; saponin; fluid; rich

SUMMARY: The berries of Sapindus mukorossi (soap nut) extracted in water, methanol and ethanol were tested for their effects on methanogenesis and fermentation of feed with buffalo rumen liquor in in vitro gas production test. The depression in methane and gas production was 96% and 39.4%, 20% and 11.5%, 22.7% and 0% with ethanol, water and methanol extracts, respectively, as compared to respective controls. The extracts also exhibited antiprotozoal activity resulting in 70-90% lesser protozoa count in the treated samples. The proportion of acetate was lower (P < 0.05) and that of propionate higher (P < 0.05) resulting in a decrease in acetate/propionate ratio with all the three extracts tested. The pH of incubation medium containing extract was significantly lower as compared with the medium without any extract. There was a significant depression in in vitro dry matter degradability of feed with all the three extracts. The data indicated that soapnut extracts appear to have a potential to be used as antimethanogenic and antiprotozoal agents.
(30-Nov-2006)
 

Cardozo PW, Calsamiglia S, Ferret A, Kamel C (2006) Effects of alfalfa extract, anise, capsicum, and a mixture of cinnamaldehyde and eugenol on ruminal fermentation and protein degradation in beef heifers fed a high-concentrate diet Journal of Animal Science 84 (10): 2801-2808

KEYWORDS: plant extract; rumen fermentation; rumen microbial fermentation; simulation technique rusitec; continuous-culture system; essential oil compounds; natural plant-extracts; yucca-schidigera; microorganism fermentation; digestive function; milk-production; malic-acid

SUMMARY: Four Holstein heifers (360 22 and 450 28 kg of BW in Exp. 1 and 2, respectively) fitted with ruminal trocars were used in 4 x 4 Latin square designs to evaluate the effects on ruminal microbial fermentation of the following: Exp. 1, no additive, alfalfa extract (30 g/d, AEX), a mixture of cinnamaldehyde (0.18 g/d) and eugenol (0.09 g/d; CIE1), and AEX and CIE1 in combination; and Exp. 2, no additive, anise oil (2 g/d), capsicum oil (1 g/d), and a mixture of cinnamaldehyde (0.6 g/d) and eugenol (0.3 g/d). Heifers were fed a 90:10 concentrate:barley straw diet (16% CP; 25% NDF) for ad libitum intake. Each period consisted of 15 d for adaptation and 6 d for sampling. On d 16 to 18, DM and water intakes were measured. On d 19 to 21 ruminal contents were sampled at 0, 3, 6, 9, and 12 h after feeding to determine ruminal pH and the concentrations of VFA, L-lactate, large peptides, small peptides plus AA (SPep+AA), and ammonia N. On d 20 and 21, samples of ruminal fluid were collected at 0 and 3 h after feeding to determine protozoal counts. In Exp. 1, CIE1 and AEX decreased (P < 0.05) total DMI, concentrate DMI, and water intake. The increase (P < 0.05) in SPep+AA and the decrease (P < 0.05) in ammonia N when supplementing CIE1 suggest that deamination was inhibited. Treatment AEX increased (P < 0.05) the acetate to propionate ratio, which is less efficient for beef production. Treatment CIE1 increased (P < 0.05) counts of holotrichs. Effects of AEX and CIE1 were not additive for many of the measured metabolites. In Exp. 2, treatments had no effect on ruminal pH, total VFA concentration, and butyrate proportion. The capsicum oil treatment increased (P < 0.05) DMI, water intake, and SPep+AA N concentration and decreased (P < 0.05) acetate proportion, branched-chain VFA concentration, and large peptide N concentration. The cinnamaldehyde (0.6 g/d) and eugenol (0.3 g/d) treatment decreased (P < 0.05) water intake, acetate proportion, branched-chain VFA, L-lactate, and ammonia N concentrations and increased (P < 0.05) propionate proportion and SPep+AA N concentration. The anise oil treatment decreased (P < 0.05) acetate to propionate ratio, branched-chain VFA and ammonia N concentrations, and protozoal counts. The results indicate that at the doses used a mixture of cinnamaldehyde and eugenol, anise oil, and capsicum oil may be useful as modifiers of rumen fermentation in beef production systems.
(30-Nov-2006)
 

Cieslak A, Miltko R, Belzecki G, Szumacher-Strabel M, Potkanski A, Kwiatkowska E, Michatowski T (2006) Effect of vegetable oils on the methane concentration and population density of the rumen ciliate, Eremoplastron dilobum, grown in vitro Journal of Animal and Feed Sciences 15: 15-18 Suppl. 1

KEYWORDS: Eremoplastron dilobum; vegetable oils; methane emission; fermentation in vitro; fatty-acids; protozoa; sheep; cattle

SUMMARY: The effect of rapeseed (RSO) and linseed (LSO) oils on the methane concentration and number of rumen ciliates (Eremoplastron dilobum) incubated in vitro was investigated. A 5% dose of rapeseed oil reduced the methane concentration by about 14% (P < 0.05) but had no effect on the ciliate number. Conversely, the same dose of LSO significantly increased the protozoa count, while methane production remained unchanged. No positive correlation was found between the methane concentration and ciliate number or with the inhibitory effect of oils rich in C 18: 1, C 18:3 fatty acids on the population density of Eremoplastron dilobum.
(30-Nov-2006)
 

Kowalik B, Pajak JJ, Dlugolecka Z, Rawa J, Michalowski T (2006) The effect of the yeast, Saccharomyces cerevisiae, on the fibrolytic activity in the rumen and on nutrient digestibility in the digestive tract of cows Journal of Animal and Feed Sciences 15: 27-30 Suppl. 1

KEYWORDS: ruminants; yeast; carboxymethylocellulase; xylanase; fibre digestibility; sheep

SUMMARY: The influence of live Saccharomyces cerevisiae yeast on the fibrolytic activity in rumen digesta and on total digestive tract nutrient digestibility in cows was examined in a 2 x 2 Latin square design. The animals were fed hay-concentrate diet alone or supplemented with yeast at the rate of 5 g/d. Addition of Sacchromyses cerevisiae decreased the activity of CMC-ase and xylanase when measured before feeding but had no effect on the diurnal variations in activity of these enzymes. The digestibility of dry matter, organic matter, crude fibre, ADF and NDF was not affected.
(30-Nov-2006)
 

Jaakkola S, Kaunisto V, Huhtanen P (2006) Volatile fatty acid proportions and microbial protein synthesis in the rumen of cattle receiving grass silage ensiled with different rates of formic acid Grass and Forage Science 61 (3): 282-292

KEYWORDS: cattle; grass silage; silage additive; formic acid; rumen fermentation; wall degrading enzymes; lactating dairy-cows; perennial ryegrass; organic-matter; nitrogen distribution; fermentation quality; nutrient utilization; effluent production; milk-production; lactic-acid

SUMMARY: Timothy-meadow fescue herbage was ensiled with formic acid (FA) (expressed as 100% solution) at the rates of 0, 2, 4 or 6 L t(-1). The silages were fed along with concentrates to bulls fitted with cannulae in the rumen and duodenum. The ration comprised grass silage (700 g kg(-1)), barley (240 g kg(-1)) and rapeseed meal (60 g kg(-1)). The application rate of FA had no effect on the site or extent of the digestion of dietary organic matter (OM) and neutral-detergent fibre. The flow of total N at the duodenum increased linearly (P < 0.05) with application rate of FA, reflecting mainly an increased (P < 0.01) flow of microbial N. The apparent efficiency of net microbial protein synthesis in the rumen increased (P < 0.05), the proportion of propionate in the volatile fatty acids (VFA) in the rumen was not affected (P > 0.05) but that of butyrate increased (linear and quadratic effects, P < 0.01) with increasing rate of FA. It is concluded that an increase in the rate of FA at ensiling leads to a higher utilization of energy and/or protein-yielding substrates for rumen microbes and to a modified rumen VFA pattern with an increased proportion of butyrate.
(30-Nov-2006)
 

Boudon A, Acosta A, Delagarde R, Peyraud JL (2006) Release of cell contents and comminution of particles of perennial ryegrass herbage during ingestion by dairy cows fed indoors or grazing Grass and Forage Science 61 (3): 205-217

KEYWORDS: dairy cows; ingestive behaviour; grazing; rumen fermentation; mastication; intracellular constituents; cattle; mastication; behavior; maturity; stage; l.; requirement; digestion; alfalfa

SUMMARY: The effect of feeding indoors fresh perennial ryegrass vs. grazing on ingestive behaviour, release of cell contents and comminution of particles during ingestion, as well as on gas production of ingested boli fermented in vitro, was studied. Indoor feeding and grazing were compared using four dairy cows according to a triple reversal design with six periods. Chemical and morphological composition of the ingested herbage was similar for both indoor feeding and grazing treatments. The intake rate was markedly higher indoors compared with grazing [52.1 vs. 22.9 g dry matter (DM) min(-1)] with heavier boli and less saliva added per gram of DM intake. The proportions of intracellular nitrogen and chlorophyll released during mastication after ingestion of herbage fed indoors were lower, and the median size of the particles in the boli was larger (5.97 vs. 4.44 mm) compared with grazing. As a result, the rate of gas production in vitro was also lower for herbage fed indoors compared with grazing (0.423 vs. 0.469 mL min(-1) g(-1) incubated DM). indoor feeding or grazing may have limited consequences in vivo on the kinetics of availability of nutrients for micro-organisms in the rumen, because the consequences of the more extensive physical damage suffered by herbage ingested at grazing could be compensated by a lower intake rate.
(30-Nov-2006)
 

Anderson RC, Carstens GE, Miller RK, Callaway TR, Schultz CL, Edrington TS, Harvey RB, Nisbet DJ (2006) Effect of oral nitroethane and 2-nitropropanol administration on methane-producing activity and volatile fatty acid production in the ovine rumen Bioresource Technology 97 (18): 2421-2426

KEYWORDS: methanogenesis; nitroethane; 2-nitropropanol; rumen; ruminal methanogenesis; in-vitro; metabolizing bacterium; salmonella-typhimurium; sheep; fermentation; microorganisms; nitrocompounds; inhibitors; reduction

SUMMARY: Strategies are sought to reduce economic and environmental costs associated with ruminant methane emissions. The effect of oral nitroethane or 2-nitropropanol administration on ruminal methane-producing activity and volatile fatty acid production was evaluated in mature ewes. Daily administration of 24 and 72 mg nitroethane/kg body weight reduced (P < 0.05) methane-producing activity by as much as 45% and 69% respectively, when compared to control animals given no nitroethane. A daily dose of 120 mg 2-nitropropanol/kg body weight was needed to reduce (P < 0.05) methane-producing activity by 37% from that of untreated control animals. Reductions in methane-producing activity may have been diminished by the last day (day 5) of treatment, presumably due to ruminal adaptation. Oral administration of nitroethane or 2-nitropropanol had little or no effect on accumulations or molar proportions of volatile fatty acids in ruminal contents collected from the sheep. These results demonstrate that nitroethane was superior to 2-nitropropanol as a methane inhibitor and that both nitrocompounds reduced ruminal methanogenesis in vivo without redirecting the flow of reductant generated during fermentation to propionate and butyrate.
(30-Nov-2006)
 

Sen AR, Santra A, Karim SA (2006) Effect of dietary sodium bicarbonate supplementation on carcass and meat quality of high concentrate fed lambs Small Ruminant Research 65 (1-2): 122-127

KEYWORDS: carcass; lambs; meat quality; sodium bicarbonate; growth-performance; rumen; fermentation

SUMMARY: Effect of sodium bicarbonate (NaHCO3) in high concentrate fed lambs was studied on carcass and meat quality characteristics. Twenty-four weaner (90 days old) Malpura lambs divided into four equal groups (G1, G2, G3 and G4) were fed basal diet (25:75 roughage: concentrate, G1) or basal diet supplemented with 0.75% (G2), 1.50% (G3) and 2.25% (G4) sodium bicarbonate for 90 days. Lambs were slaughtered for carcass and meat quality evaluation. Longissimus dorsi was collected and analysed for meat quality traits. Pre-slaughter weight was higher (P < 0.05) in sodium bicarbonate-supplemented (G2, G3, and G4) groups than in the control group (G1). The muscular development as indicated by loin eye area was higher (P < 0.05) in the treatment groups (G2, G3 and G4) as compared to control. There were no significant differences (P > 0.05) in visceral fat contents in lambs of control and treated groups. The carcass fat content was lesser (P < 0.05) in treated lambs than control groups. In leg, the lean content was more (P < 0.05) in treated groups (G3 and G4) as compared to control (G1). Cook loss% was higher (P < 0.05) in treated groups as compared to control. There was no significant difference (P > 0.05) in shear force value of meat from control or treated lambs. It is concluded from the study that dietary supplementation of sodium bicarbonate in high concentrate diets did not exert much influence on carcass and meat quality characteristics. However, the dressing yield improved and total separable carcass fat was reduced by supplementing buffer to high concentrate fed lambs.
(30-Nov-2006)
 

Sauvant D, Giger-Reverdin S, Meschy F (2006) The control of latent ruminal acidosis Productions Animales 19 (2): 69-78 (in French)

KEYWORDS: saccharomyces-cerevisiae culture; lactate utilization; rumen; supplementation; growth; diet; cows

SUMMARY: The major item to assess ruminal acidosis is the mean pH of rumen juice for several hours after a meal. Other criteria have been proposed, however they are closely related to the mean pH and do not provide more relevant information. Various types of measurements can be performed on feeds, or diets, to evaluate the risk of latent acidosis. Individual feeds can be assessed in terms of buffering capacity, in vitro fermentability or pH drop capacity, and in sacco short term (4h) DM diseappearance. Other parameters can be measured, such as in particular the degradable starch for starchy ingredients. Otherwise, the cation-anion balance can be calculated to assess one of the components of feed and diet acidogenicity. Diet fibrosity is a major factor of variation of the risk of acidosis. In fact, there are two components of fibrosity: the chemical fibrosity, assessed by the dietary NDF (NDF%DM > 35%), and the physical one, assessed by either the mean particle size (MPS > 4mm) or the dietary DM retained by a 2mm aperture sieve (P2 > 40%DM). It is also possible to combine these two types of parameters. Fibrosity items are very important because they determine the chewing activities and thus the salivary buffer recycling and the liquid flow throughout the rumen. These items seem to be more influent than those predicting the VIA production. Other aspects affect ruminal acidosis such as the level of intake and the role of some microbial sub populations in the rumen such as the protozoa. Otherwise, beyond the feeding factors, diets can be corrected to prevent acidosis by supplementation of buffer substances or probiotics. The proposed equations and recommendantions allow to integrate various items to formulate diets preventing the risk of latent acidosis.
(30-Nov-2006)

Berthiaume, R., Mandell, I., Faucitano, L., Lafrenière, C. 2006. “Comparison of alternative beef production systems based on forage finishing or grain-forage diets with or without growth promotants: 1. Feedlot performance, carcass quality, and production costs”. J. Anim. Sci. 84: 2168-2177.

KEYWORDS: Beef production system, Feedlot performance, Forage finishing, Production cost

SUMMARY: Forty Angus-cross steers were used to evaluate 5 beef cattle management regimens for their effect on growth performance, carcass characteristics, and cost of production. A 98-d growing phase was incorporated using grass silage with or without growth promotants (trenbolone acetate + estradiol implants, and monensin in the feed) or soybean meal. Dietary treatments in the finishing phase were developed, with or without addition of the same growth promotants, based on exclusive feeding of forages with minimal supplementation or the feeding of barley-based diets. Overall, ADG for animals treated with growth promotants or fed supplemented diets (soybean meal and barley) was increased (P < 0.01) by 25 and 21%, respectively, compared with steers reared on grass silage alone and not treated with growth promotants. Except for HCW (P < 0.01), the use of growth promotants did not affect carcass measurements. Increasing the proportion of barley in the diet of steers finished on forage produced a heavier HCW (P < 0.01) and a greater (P < 0.01) quality grade. Because of their lower HCW and quality grade, cattle targeted to a forage-fed, nonimplanted beef market would need to garner a 16% premium to be economically competitive with cattle finished conventionally.
(16-Oct-2006)
 

Stercova E., Haas D., Krasa A., Lepkova R., Sterc J. (2006) “Effect of intensive fattening of bulls fed a high-grain diet on selected health indicators” Acta Vet. BRNO 75(2):209-18.

KEYWORDS: feeding; concentrate; rumen fermentation; acid-base balance; bone metabolism

SUMMARY: This study aimed to investigate the effect of intensive bulls fattening with a high-grain diet (HGD) on selected health parameters. Metabolic indicators were compared with those in bulls receiving a traditional diet (TD) based on maize silage. The trial compared 18 Czech pied bulls fed a HGD containing from 75.0% to 83.6% concentrate on dry matter basis with 18 Czech pied bulls fed a TD. The experiment started after weaning when animals averaged 115 days of age. Bulls were slaughtered at an average age of 474 days. In the fattening period, blood and rumen fluid samples were withdrawn to evaluate rumen fermentation, acid-base balance and selected biochemical indicators. After slaughter, samples of tuber coxae cancellous tissue were collected for the bone metabolism assessment. The rumen fermentation indicators were the most affected by feeding the HGD. HGD Bulls showed lower rumen fluid pH and a higher total titration activity, a higher total level of VFA and propionate proportion, and a lower acetate proportion than TD bulls. Counts of infusoria were also lower. Acid-base balance was not influenced by feeding the HGD. HGD bulls showed increased serum levels of AST and phosphorus, but the differences from TD bulls were non-significant in most cases. In Ig bone ash of the samples of tuber coxae cancellous tissue in the treated group calcium content was lower than in TD; no differences were observed between other indicators under investigation.
(16-Oct-2006)
 

Brosh A, Henkin Z, Orlov A, Aharoni Y (2006) Diet composition and energy balance of cows grazing on Mediterranean woodland Livestock Science 102 (1-2): 11-22

KEYWORDS: beef cattle; grazing cows; Mediterranean browse; botanical composition; heart rate; energy expenditure; energy balance; plant cuticular wax; heart-rate; poultry litter; beef-cattle; alkanes; expenditure; herbage; herbivores; nutrition; responses

SUMMARY: The study was conducted to determine the role of browse in the nutritional status and performance of beef cattle grazing on Mediterranean woodland. Measurements of the botanical intake composition (using N-alkane control release capsules and profile) and of the energy expenditure (EE) and balance (using the heart rate method) were carried out on six pregnant cows in the late summer, and on the same cows when nursing in winter and after weaning in late spring. Broiler chicken manure (poultry litter, PL) was given freely during late summer and in winter. Throughout the three periods the metabolizable energy (ME) concentrations of the consumed diet were 6.23, 8.78, 7.65 MJ/kgDM, respectively and the intakes were 8.59, 9.60, 7.92 kgDM/day, respectively; the ME intake, the EE and the retained energy (all in units of kJ/(kgLW(0.75)*day) were 583, 524 and 58, respectively, in late summer; 960, 634 and 326, respectively, in winter; and 665, 475 and 190, respectively, in late spring. The proportions of woody plants in the consumed diet were 63%, 15% and 59% in the respective periods. The proportion of PL supplement in the diet was 37% in late summer and 35% in winter. We conclude that browse can provide 60% of the MEI, and thus the performance of cows grazed on woodland was comparable with that of cows grazed on herbaceous ranges in this region.
(16-Oct-2006)

Brosh A, Henkin Z, Ungar ED, Dolev A, Orlov A, Yehuda Y, Aharoni Y (2006) Energy cost of cows' grazing activity: Use of the heart rate method and the Global Positioning System for direct field estimation Journal of Animal Science 84 (7): 1951-1967

KEYWORDS: cattle; energy cost; energy expenditure; global positioning system; grazing; heart rate; mediterranean pasture; oxygen-consumption; seasonal-variation; stocking rate; expenditure; cattle; locomotion; balance; walking; range

SUMMARY: This study with grazing beef cows on the range was designed to explore the possibility of determining incremental energy expenditure (EE) in standing, traveling, and grazing relative to that in lying down, by means of continuous monitoring of EE, location, and activity by the heart-rate method, with Global Positioning System (GPS) collars, and by motion sensors in the GPS collars, respectively. Cows were observed on Mediterranean foothill rangeland covered with herbaceous vegetation through 4 seasons of the year. There were 2 stocking rate treatments, and 14 statistical models were evaluated, including one that was a stepwise model. Total daily EE (TEE) was affected by many interdependent factors apart from activity, including season, stocking rate, herbage quality, standing biomass, and reproductive state of the cow. Each model included all activity variables, plus some of the other factors. Across seasons and treatments TEE, in kJ/kg of BW 0.75/d, ranged from 469 in densely stocked, nonlactating cows in June to 1,092 in sparsely stocked, lactating cows in April. The cows' daily vertical and horizontal movements ranged from 75 to 174 in and from 1.5 to 4.2 km, respectively. Within a day, time spent traveling (without grazing) ranged from 0 to 32 min, and grazing time ranged from 4.4 to 12.1 h. Cows spent less time grazing (P < 0.00 1) in the summer, when herbage quality was low, than in winter and spring. Relative to the baseline EE while lying down, the daily increment incurred by grazing ranged from 13 to 48 kJ/ kg of BW 0.75/d, and that incurred by grazing, standing, and traveling combined ranged from 38 to 74 kJ/ kg of BW 0.75/d or 5.8 to 11.4% of TEE. In conclusion, the estimates of activity costs yielded by 11 of the models were similar to one another, whereas those yielded by the stepwise model and the remaining 2 models were 20% smaller. The cost of grazing activity was estimated to be 6.14 J/ kg of BW 0.75/d, and that of locomotion during grazing was 6.07 J/ kg of BW 0.75/d, which agree with values obtained for animals and humans by means of a treadmill. The experimental and statistical approach tested here yielded fairly reliable estimations of energy costs of activities in grazing cows.
(16-Oct-2006)
 

Stahlhut HS, Whisnant CS, Lloyd KE, Baird EJ, Legleiter LR, Hansen SL, Spears JW (2006) Effect of chromium supplementation and copper status on glucose and lipid metabolism in Angus and Simmental beef cows Animal Feed Science and Technology 128 (3-4): 253-265

KEYWORDS: chromium; cattle; copper; glucose tolerance; stressed feeder calves; carcass characteristics; finishing steers; performance; growth; insulin; breed; picolinate; charolais; tolerance

SUMMARY: Pregnant Angus (n = 83) and Simmental (n = 69) cows were blocked by age into three blocks and then randomly assigned by breed to one of two free choice mineral supplements to determine effects of dietary Cr and Cu status on glucose metabolism and blood metabolites in beef cows. Supplements consisted of: (1) control (no supplemental Cr) and (2) 40 mg Cr/kg of mineral (from Cr picolinate). Mineral supplements were formulated to contain all minerals typically supplemented to cattle diets with the exception of Cu. The study began approximately 75 days prepartum, at which time half of the cows in each treatment received a 25 g Cu oxide needle bolus. Blood was collected from 36 cows on days 28, 58, 97 (approximately 20-day postpartum), 155, 210, and 279 for plasma glucose and non-esterified fatty acid (NEFA) determination. Chromium supplementation reduced (P < 0.05) plasma glucose concentrations. Plasma glucose concentrations were also affected by breed x Cu bolus (P < 0.05). In non-Cu supplemented cows, plasma glucose levels were higher (P < 0.05) in Angus versus Simmental cows. In cows receiving a Cu bolus, plasma glucose levels were similar between breeds. Plasma NEFA concentrations were affected by time (P < 0.01), Cr x Cu bolus (P < 0.05), Cr x time (P < 0.01), and Cr x block (P < 0.01). On days 97 and 155, plasma NEFA concentrations were lower (P < 0.01) in cows receiving Cr relative to control cows. Chromium supplementation reduced (P < 0.01) plasma NEFA concentrations in 2 and 3 and 4 and 5-year-old cows but not in older cows, relative to control cows in those blocks. Chromium supplemented cows had lower (P < 0.05) plasma NEFA concentrations than control cows that did not receive a Cu bolus. No differences in plasma NEFA concentrations occurred between treatments in cows that received a Cu bolus. At approximately 1-month prepartum and 1-month postpartum, 12 cows were cannulated in their jugular vein and glucose tolerance tests (GTT) were conducted. Cows used in GTT received 0.15 g of glucose/kg body weight as a 500 g/L dextrose solution. Chromium supplemented cows had lower plasma glucose (P < 0.01), serum insulin (P < 0.05) and NEFA (P < 0.01) concentrations following the GTT conducted prepartum versus control cows. Clearance rates for glucose were not affected by treatment. In the postpartum GTT, plasma glucose was affected by an interaction between Cr supplementation and Cu status, as Cr supplemented cows that received a Cu bolus had higher (P < 0.001) plasma glucose after glucose administration than cows not supplemented with Cu. No differences in plasma glucose occurred between control cows regardless of Cu status. Chromium supplemented cows had lower (P < 0.05) serum insulin concentrations 10-45 min after glucose administration versus control cows. Results indicate that plasma glucose is lower in cows receiving supplemental Cr, and that an interaction between Cr and Cu status may alter glucose metabolism.
(16-Oct-2006)
 

Stahlhut HS, Whisnant CS, Spears JW (2006) Effect of chromium supplementation and copper status on performance and reproduction of beef cows Animal Feed Science and Technology 128 (3-4): 266-275

KEYWORDS: chromium; cattle; reproduction; performance; stressed feeder calves; dietary copper; immune-response; dairy-cows; disease resistance; finishing steers; cattle; angus; molybdenum; gestation

SUMMARY: Pregnant Angus (n = 83) and Simmental (n = 69) cows were blocked by age into three age blocks and then randomly assigned by breed within a block to one of two free choice mineral supplements to determine effects of dietary Cr and Cu status on performance and reproduction of beef cows. Supplements consisted of: (1) control (no supplemental Cr) and (2) 40 mg Cr/kg of mineral (from Cr picolinate). Mineral supplements were formulated to contain all minerals typically supplemented to cattle diets with the exception of Cu. The study began approximately 75 days prepartum, at which time half of the cows in each treatment received a 25 g Cu oxide needle bolus. Blood was collected from 36 cows on days 0, 28, 58, 97 (approximately 20 days postpartum), 155, 210, and 279, and from 36 calves on days 196 and 279 for plasma Cu determination. Liver biopsies were taken on days 0 and 279 to determine initial and final liver Cu concentrations in cows. Plasma Cu concentrations were affected by Cu bolus x time (P < 0.05), breed x time (P < 0.01), and breed x bolus (P < 0.01) interactions in cows, and by a treatment x time interaction (P < 0.05) in calves. Liver Cu concentrations were affected by breed x time (P < 0.01) and Cu bolus x time (P < 0.05) in cows. Cows receiving a Cu bolus had higher (P < 0.05) plasma Cu on day 97, and higher (P < 0.05) liver Cu on day 279 relative to cows that did not receive a bolus. Simmental cows had lower (P < 0.01) plasma Cu at day 28 and at subsequentsampling days, and lower (P < 0.01) liver Cu on days 0 and 279 than Angus cows. Simmental cows that received a Cu bolus had higher (P < 0.01) plasma Cu concentrations than Simmentals that did not receive supplemental Cu. Supplemental Cr resulted in higher (P < 0.05) plasma Cu concentrations in calves on day 279 versus controls. Overall body weight loss and body weight loss postpartum in cows was affected by breed (P < 0.05) and treatment x block (P < 0.01). Overall and postpartum body weight loss was lower in Angus cows (P < 0.05). Chromium supplementation reduced (P < 0.01) overall and postpartum body weight. loss in 2 and 3 years old cows, but not in older cows. Cows supplemented with Cr tended (P < 0.06) to have higher pregnancy rates than controls. Calf birth weights and weaning weights were not affected by Cr or Cu bolus. Results indicate that Cr supplementation may improve fertility and decrease postpartum body weight loss especially in young beef cows.
(16-Oct-2006)
 

Fujita T, Kajita M, Sano H (2006) Responses of whole body protein synthesis, nitrogen retention and glucose kinetics to supplemental starch in goats Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology 144 (2): 180-187

KEYWORDS: amino acid absorption; energy intake; glucose kinetics; goat; isotope dilution; nitrogen retention; phenylatanine; protein synthesis; starch; tyrosine; amino-acids; leucine metabolism; lysine metabolism; energy-intake; beef steers; food-intake; young men; turnover; sheep; plasma

SUMMARY: An isotope dilution experiment was conducted to determine the effect of metabolizable energy intake (MEI) as starch on whole body protein synthesis (WBPS), nitrogen (N) retention and glucose irreversible loss rate (ILR) in four adult goats (Capra hircus). The goats were fed isonitrogenous diets containing three different metabolizable energy (1.0, 1.5 and 2.0 times maintenance) twice daily. Energy above maintenance was supplemented with cornstarch. The WBPS and glucose ILR during 5 to 7 h after feeding were measured by a primed-continuous infusion of [H-2(5)]phenylalanine', [H-2(2)]tyrosine, [H-2(4)]tyrosine and [C-13(6)]glucose for 4 h, with measurements of plasma concentrations of metabolites and insulin. Ruminal characteristics were also determined. Increasing MEI improved N retention, despite decreased digestible N. Increasing MEI decreased ruminal pH and ammonia nitrogen. In plasma, decreased urea N, increased total amino N and tyrosine, and trends for increases in phenylalanine and insulin resulted from increasing MEI. Increasing MEI increased ILR of glucose, phenylalanine and tyrosine, and hydroxylation rate of phenylalanine and WBPS. We conclude that in goats increasing MEI as starch enhances WBPS in the absorptive state and N retention, despite a decrease in digestible N. These changes are probably associated with both decreased ammonia absorption and increased amino acid absorption.
(16-Oct-2006)
 

Kelliher FM, Clark H, Zheng L, Newton PCD, Parsons AJ, Rys G (2006) A comment on scaling methane emissions from vegetation and grazing ruminants in New Zealand Functional Plant Biology 33 (7): 613-615

KEYWORDS: grazed pasture; livestock; forest; sheep; soil

SUMMARY: Keppler et al. (2006, Nature 439, 187-191) showed that plants produce methane (CH4) in aerobic environments, leading Lowe (2006, Nature 439, 148-149) to postulate that in countries such as New Zealand, where grazed pastures have replaced forests, the forests could have produced as much CH4 as the ruminants currently grazing these areas. Estimating CH4 emissions from up to 85 million ruminants in New Zealand is challenging and, for completeness, the capacity of forest and pastoral soils to oxidise CH4 should be included. On average, the CH4 emission rate of grazing ruminants is estimated to be 9.6 +/- 2.6g m(-2) year(-1) (+/- standard deviation), six times the corresponding estimate for an indigenous forest canopy (+/- 1.6 +/- 1.1g m(-2) year(-1)). The forest's soil is estimated to oxidise 0.9 +/- 0.2g m(-2) year(-1) more CH4 than representative soils beneath grazed pasture. Taking into account plant and animal sources and the soil's oxidative capacity, the net CH4 emission rates of forest and grazed ecosystems are 0.6 +/- 1.1 and 9.8 +/- 2.6 g m(-2) year(-1), respectively.
(16-Oct-2006)
 

Wright ADG, Toovey AF, Pimm CL (2006) Molecular identification of methanogenic archaea from sheep in Queensland, Australia reveal more uncultured novel archaea Anaerobe 12 (3): 134-139

KEYWORDS: methanogens; Methanobrevibacter; rumen ecology; ruminants; sheep; RDNA sequence-analysis; directed pcr primers; phylogenetic analysis; microbial diversity; rumen; community; methane; tracts; rates; diet

SUMMARY: Molecular diversity of rumen methanogens in sheep in Queensland, Australia was investigated using 16S rRNA gene libraries prepared from pooled rumen contents from nine merino sheep. A total of 78 clones were identified revealing 26 different sequences. Of these 26 sequences, eight sequences (15 clones) were 95-100% similar to cultivated methanogens belonging to the orders Methanobacteriales and Methanomicrobiales, and the remaining IS phylotypes (63 clones) were 72-75% similar to Thermoplasma acidophilum and Thermoplasma volcanium. These unique sequences clustered within a distinct and strongly supported (100% bootstrap support) phylogenetic group, exclusively composed of sequences from uncharacterized archaea from very diverse anaerobic environments. Members of this unique group that were previously considered atypical for the rumen environment were the predominant clones.
(16-Oct-2006)
 

Lee MRF, Colmenero JDO, Winters AL, Scollan ND, Minchin FR (2006) Polyphenol oxidase activity in grass and its effect on plant-mediated lipolysis and proteolysis of Dactylis glomerata (cocksfoot) in a simulated rumen environment Journal of the Science of Food and Agriculture 86 (10): 1503-1511

KEYWORDS: lipolysis; proteolysis; polyphenol oxidase; grass; plant enzymes; perennial ryegrass; tall fescue; red-clover; phenolic-compounds; upland conditions; timothy pastures; acid-composition; proteins; degradation; growth

SUMMARY: Little is known about the level or activity of polyphenol oxidase (PPO) in grasses and its potential impact on proteolysis and lipolysis. Six grass species were initially screened for PPO activity (740.6, 291.9, 213.6, 119.0, 16.3 and 6.5 U g(-1) fresh weight (FW) for cocksfoot, hybrid ryegrass, Italian ryegrass, perennial ryegrass, timothy and tall fescue respectively). Cocksfoot, which expressed the highest activity, was then used to determine the effect of PPO on plant-mediated proteolysis and lipolysis in a simulated rumen environment. Sourced cocksfoot was macerated and incubated in an antibiotic-containing anaerobic medium with or without ascorbate to deactivate PPO in the dark at 39 degrees C over five time points. At each time point (0, 1, 2, 6 and 24h), six replicate samples were destructively harvested; three of the replicates were used for lipid analysis and the other three for protein, free amino acid and bound phenol determination. Characterisation of the herbage showed PPO activities of 649.6 and 0 U g(-1) FW, which were reflected in the extent of phenol (derived from quinones) binding to protein after 24h of incubation, namely 65.1 and 29.6mg bound phenol g(-1) protein (P < 0.001) for cocksfoot and cocksfoot + ascorbate respectively. Proteolysis, measured as free amino acids released into the incubation buffer, was significantly reduced (P < 0.001) with increasing PPO activity, with values after the 24h incubation of 0.03 and 0.07 mmol L-1 g(-1) FW for cocksfoot and cocksfoot + ascorbate respectively. Lipolysis, measured as the proportional decline in the membrane lipid polar fraction, was likewise reduced (P < 0.001) with increasing PPO activity, with values after the 24 h incubation of 0.43 and 0.65 for cocksfoot and cocksfoot + ascorbate respectively. Changes that occurred in protein and the lipid fractions (polar fraction, monoacylglycerol + diacylglycerol, triacylglycerol and free fatty acids) during the incubations are also reported and discussed. These results support the selection of forages high in PPO activity to reduce protein and lipid losses in silo and potentially in the rumen.
(16-Oct-2006)
 

Akraim F, Nicot MC, Weill P, Enjalbert F (2006) Effects of preconditioning and extrusion of linseed on the ruminal biohydrogenation of fatty acids. 2. In vitro and in situ studies Animal Research 55 (4): 261-271

KEYWORDS: biohydrogenation; linseed; preconditioning; extrusion; in vitro; in situ; conjugated linoleic-acid; dairy-cows; milk-fat; rumen; soybeans; digestibility; isomers; canola; trans; raw

SUMMARY: The extent and/or intermediates of ruminal biohydrogenation ( BH) of fatty acids ( FA) were investigated in vitro and in situ using a raw, pre-conditioned or extruded blend of linseed and wheat bran ( 70: 30). The duration of in vitro incubations were 2, 4, 8, 16 and 24 h, with 5 replicates. In situ studies used 3 dry ruminally fistulated Holstein cows in a 3 x 3 Latin square design, with 3 weeks adaptation to the linseed form. The diet contained 20% (DM basis) of the linseed based blend. The duration of in situ incubations were 2, 4, 8, 16, 24 and 48 h. BH was much slower in situ than in vitro, resulting in a much lower effective disappearance of C18:2 and C18:3. Moreover, the in situ technique suggested that the technological pre-treatment of linseed did not affect C18: 2 and C18: 3 rate of BH, whereas reduced rates were observed in vitro. After 8 h of in vitro incubation and onwards, proportions of cis-9, trans-11C18:2 were the highest with extruded linseed. The BH of FA from linseed resulted in the appearance of great proportions of trans-10+11 to trans-16C18:1 intermediates. Extrusion increased the proportions of trans-10+11C18:1 both in vitro and in situ and proportions or trans-C18:1 were higher in situ than in vitro. Compared to previous in vivo results with the same material, the in situ method provided poor estimates of BH rates and intermediates.
(16-Oct-2006)
 

Shingfield KJ, Toivonen V, Vanhatalo A, Huhtanen P, Griinari JM (2006) Short communication: Indigestible markers reduce the mammary Delta(9)-desaturase index and alter the milk fatty acid composition in cows Journal of Dairy Science 89 (8): 3006-3010

KEYWORDS: Delta(9)-desaturase; marker; milk fatty acid; conjugated linoleic acid; conjugated linoleic-acid; lactating dairy-cows; fish-oil; digesta; desaturation; concentrate; isomers; copper; trans

SUMMARY: Accurate determination of the flow of nutrients at the omasum requires the use of a triple marker system. Typically, a system based on ruminal administration of the lithium salt of CoEDTA, ytterbium acetate (YbAc), and chromium-mordanted straw (Cr-S) has been used. However, there is evidence to suggest that product: substrate ratios for stearoyl-coenzyme A desaturase (Delta(9)-desaturase) are lower in milk fat from cows administered a combination of CoEDTA, Yb-Ac, and Cr-S, indicating reduced delta-9- desaturase activity. To evaluate this hypothesis, samples of milk were collected 1 d before, and on d 2, 6, and 9 of administering the CoEDTA, Yb-Ac, and Cr-S triple marker system into the rumen of 4 cows. A 4 x 4 Latin square with 28-d experimental periods was used to assess the effects of 0, 75, 150, and 300 g/d of fish oil in the diet on ruminal and mammary lipid metabolism. Irrespective of the amount of fish oil in the diet, concentrations of all milk fatty acids containing a cis-9 double bond were reduced after markers were given. Milk fatty acid pairs dependent on Delta(9)-desaturase were decreased over time, with responses reaching a nadir within 6 d of marker administration. Overall, administering markers into the rumen was associated with a mean decrease in milk cis-9 10: 1/10: 0, cis-9 12: 1/12: 0, cis-9 14: 1/14: 0, cis-9 16: 1/16: 0, cis-9 17: 1/17: 0, cis-9 18: 1/18: 0, and cis-9, trans-11 conjugated linoleic acid/trans-11 18: 1 concentration ratios of 44.6, 52.7, 58.7, 36.8, 37.2, 44.3, and 43.0%, respectively. In conclusion, one or more of the markers administered altered milk fatty acid composition and may act as an inhibitor of Delta(9)-desaturase in the bovine mammary gland.
(16-Oct-2006)
 

Resende JC, Pereira MN, Boer H, Tamminga S (2006) Comparison of techniques to determine the clearance of ruminal volatile fatty acids Journal of Dairy Science 89 (8): 3096-3106

KEYWORDS: volatile fatty acid; rumen; clearance rate; absorption; lactating dairy-cows; fiber digestion; rumen mucosa; absorption; diets; disappearance; kinetics; acidosis; starch; cattle

SUMMARY: The objective of this experiment was to compare measurements of fractional clearance rates obtained by using an unlabeled valerate-CoEDTA technique with measurements obtained by using a C-13-labeled volatile fatty acids (VFA) technique. The exponential decay rate of the C-13/C-12 ratio after pulse-dosing C-13-acetate, C-13-propionate, or C-13-butyrate into the rumen was compared with the decay rate of rumen valerate concentration following a simultaneous pulse dose. The unlabeled valerate, CoEDTA, and each labeled VFA, one at a time, were concurrently mixed with the evacuated ruminal content of 6 lactating cows in two 3 x 3 Latin squares. The clearance of VFA by passage to the omasum was assumed to be equivalent to the decay in ruminal Co concentration and was around 50% of the total clearance. Acetate, propionate, and butyrate had similar fractional clearance rates (31.2, 33.4, 30.4%/h, respectively), but propionate had a higher absorption rate (19.2%/h) than butyrate (14.2%/h). Linear regression determination coefficients using the valerate clearance rate as an estimator for acetate, propionate, and butyrate rumen clearance were 0.51, 0.56, and 0.99, respectively. In a second experiment, the C-13-valerate fractional clearance rate estimate (33.7%/h) was similar to the estimate obtained with unlabeled valerate (35.0%/h) by the valerate-Co technique. No C-13 enrichment of rumen microbes was noted 4 h after the intraruminal infusion of C-13-valerate. Fractional VFA absorption rate estimates obtained in both techniques were similar, although both were lower than estimates reported in the literature by other methods.
(16-Oct-2006)
 

Tafaj M, Schollenberger M, Feofilowa J, Zebeli Q, Steingass H, Drochner W (2006) Relationship between thiamine concentration and fermentation patterns in the rumen fluid of dairy cows fed with graded concentrate levels Journal of Animal Physiology and Animal Nutrition 90 (7-8): 335-343

KEYWORDS: rumen; thiamine; fermentation patterns; dairy cows; hay; concentrate ratio; performance liquid-chromatography; in-vitro; supplementation

SUMMARY: The objective of this study was to investigate the relationship between the thiamine concentration and the fermentation patterns [pH, concentration of short-chain fatty acids (SCFA)] in the free liquid (FRL) and particle-associated liquid (PARL) of the rumen in dairy cows fed with graded concentrate levels in the diet. Four ruminally cannulated Holstein cows in mid lactation were fed [semi-ad libitum, 18 kg dry matter (DM)/day] diets consisting of hay (H) and slowly degradable concentrate (C), offered in five different H:C ratios (% DM basis) in the following sequence: period 1, 30:70; period 2, 40:60; period 3, 50:50; period 4, 60:40 and period 5, 75:25. A negative quadratic relationship was observed between thiamine concentration in FRL and intake of dietary thiamine (R2 = 0.36), of concentrate (R2 = 0.38) and of digestible non-fibre carbohydrates (R2 = 0.37). The thiamine concentration in PARL was higher (p <= 0.05) compared to FRL. The ruminal thiamine concentration correlated negatively to pH and positively to concentrations of SCFA and propionate in the rumen. R2 of these relationships varied markedly (0.002 and 0.77), depending on time after feeding and fluid digesta compartment. The higher R2 were observed at 8 and 11 h after the morning feeding for FRL (R2 0.46-0.71) and PARL (R2 0.41-0.77), respectively.
(16-Oct-2006)
 

Lovett DK, Stack L, Lovell S, Callan J, Flynn B, Hawkins M, O'Mara FP (2006) Effect of feeding Yucca schidigera extract on performance of lactating dairy cows and ruminal fermentation parameters in steers Livestock Science 102 (1-2): 23-32

KEYWORDS: dairy cows; Yucca schidigera; digestibility; rumen fermentation; performance; steroidal saponins; nutrient digestion; shidigera extract; alfalfa saponins; rumen; concentrate; sarsaponin; metabolism; bacteria; nitrogen

SUMMARY: Two experiments were conducted to determine the effects of Yucca schidigera extract (YE) on firstly, dry matter intake (DMI), milk production and milk composition in lactating Holstein Friesian cows and secondly on DMI and GEI and rumen fermentation parameters of ruminally fistulated Holstein Friesian steers. Three levels of YE supplementation were studied in both experiments. In Experiment 1, 33 early lactating dairy cows that were 69 days in milk (S.D. +/- 39) at cornmencement of the trial were fed YE at either 0, 25 or 50 g/head/day in a randomised block design while in Experiment 2, the three fistulated steers were fed YE at 0, 15 and 28 g/head/day within a latin square design. The lower levels of YE supplementation fed in Experiment 2 were designed to provide similar inclusion rates within the diet as in Experiment 1 after allowing for the higher DMI within Experiment 1. All animals in both trials were offered ad libitum a total mixed ration (TMR) supplemented with concentrates containing the YE, The dairy cows were group housed by diet, however when milk and intake measurements were conducted (days 12 to 18 and days 54 to 60 post commencement of the feeding of the experimental diets) the animals were housed in individual tie up stalls, whereas for Experiment 2 all animals were individually stall fed for the duration of the trial. Feeding YE had no effect on milk yield or composition, however DMI decreased linearly (P < 0.06) in response to increasing YE dietary inclusion within Experiment 1. No effects of YE supplementation on total tract digestibility were identified in either experiment, however comparisons between treatments revealed that total volatile fatty acid (VFA) concentration in rumen fluid were lower at for both YE25 and YE50 relative to the control, and rumen protozoa numbers were also linearly (P < 0.01) reduced. Although feeding YE to early lactation Holstein Friesian cows had no effect on milk production or digestibility and had only elicited limited responses in rumen fermentation characteristics it would appear to lead to an increase in the efficiency of converting feedstuffs to milk (as comparisons between individual treatments revealed a significant increase following YE supplementation relative to YE0) due to a reduction in voluntary DMI.
(16-Oct-2006)
 

DiLorenzo N, Diez-Gonzalez F, DiCostanzo A (2006) Effects of feeding polyclonal antibody preparations on ruminal bacterial populations and ruminal pH of steers fed high-grain diets Journal of Animal Science 84 (8): 2178-2185

KEYWORDS: Streptococcus bovis; Fusobacterium necrophorum; polyclonal antibodies; high-concentrate diet; direct-fed microbials; escherichia-coli; egg-yolk; fusobacterium-necrophorum; streptococcus-bovis; neonatal calves; lactic-acidosis; rumen bacteria; feedlot cattle

SUMMARY: Three experiments with factorial arrangements of treatments were designed to test the efficacy of avian-derived polyclonal antibody preparations (PAP) against Streptococcus bovis (PAP-Sb) or Fusobacterium necrophorum (PAP-Fn) in reducing ruminal counts of target bacteria in beef steers supplemented or not with feed additives (300 mg of monensin/ d and 90 mg of tylosin/d; MT). Feeding increasing doses of PAP-Sb in Exp. 1 or a single dose in Exp. 2 reduced S. bovis counts in a cubic fashion (P = 0.014). In Exp. I and 2, inclusion of MT in the diet had no effect (P > 0.05) on ruminal S. bovis counts. In Exp. 2, ruminal pH was increased (P < 0.05) by feeding PAP-Sb, MT, and PAP-Sb plus MT. Ruminal F. necrophorum counts were reduced by feeding PAP-Fn (P = 0.002) and MT (P < 0.001). Reduction in ruminal F. necrophorum counts was greater (P = 0.008) when feeding MT alone than when feeding PAP-Fn and MT together. In Exp. 3, ruminal S. bovis counts were not affected (P = 0.64) by PAP-Fn. Ruminal pH was not affected (P = 0.61) by feeding PAP-Fn, and the total anaerobic bacterial count was not affected (P > 0.05) by either PAP-Sb or PAP-Fn in Exp. 1 or Exp. 3. In conclusion, PAP of avian origin and against S. bovis or F. necrophorum were effective in reducing target ruminal bacterial populations. These PAP could be effective in preventing the deleterious effects associated with these bacteria, and possibly in enhancing animal performance.
(16-Oct-2006)
 

Freetly HC, Nienaber JA, Brown-Brandl T (2006) Partitioning of energy during lactation of primiparous beef cows Journal of Animal Science 84 (8): 2157-2162

KEYWORDS: cow; energy; heat production; milk-production; maintenance; efficiency; weight; cattle; birth

SUMMARY: For a beef cow to continue in an annual production cycle, she must rebreed within 3 mo after calving. Malnutrition during this period frequently results in failure of the cow to become pregnant. The energetic needs of the cow are increased by lactation, and additional energy is required for growth of the primiparous cow. Determining energy expenditures during the first 40 to 60 d postpartum is critical to developing feed programs that will allow cows to become pregnant with a second calf. Sixty-seven balance trials were conducted on 25 MARC III cows (4-breed composite: (1)/(4) Hereford, (1)/(4) Angus, (1)/(4) Red Poll, and (1)/(4) Pinzgauer) that were between 3 and 53 d in milk. Cows' BW were 481 +/- 4 kg. Metabolizable energy intake ranged from 14.8 to 28.9 Mcal/d. Milk yields ranged from 4.7 to 13.3 kg/d. Recovered energy (RE) increased linearly with increased ME intake. Forty-seven observations were obtained with cows in negative tissue energy (TE) balance, and 20 observations were obtained with cows in positive TE balance. Estimated zero RE from regression analysis of RE on ME intake was 146 kcal of ME/kg of BW0.75. Efficiency of conversion of ME to lactation energy (LE) was 72%. The efficiency for conversion of ME to TE and the conversion of TE to LE was 78%. Our findings suggest that, even though their milk production is lower, the overall efficiency of energy retention in young beef cows is similar to that of dairy cows.
(16-Oct-2006)
 

Berthiaume R, Mandell I, Faucitano L, Lafreniere C (2006) Comparison of alternative beef production systems based on forage finishing or grain-forage diets with or without growth promotants: 1. Feedlot performance, carcass quality, and production costs Journal of Animal Science 84 (8): 2168-2177

KEYWORDS: beef production system; feedlot performance; forage finishing; production cost; steers fed grass; high moisture barley; x shorthorn bulls; estradiol benzoate; anabolic implant; holstein steers; alfalfa silage; cross steers; protein; cattle

SUMMARY: Forty Angus-cross steers were used to evaluate 5 beef cattle management regimens for their effect on growth performance, carcass characteristics, and cost of production. A 98-d growing phase was incorporated using grass silage with or without growth promotants (trenbolone acetate + estradiol implants, and monensin in the feed) or soybean meal. Dietary treatments in the finishing phase were developed, with or without addition of the same growth promotants, based on exclusive feeding of forages with minimal supplementation or the feeding of barley-based diets. Overall, ADG for animals treated with growth promotants or fed supplemented diets (soybean meal and barley) was increased (P < 0.01) by 25 and 21%, respectively, compared with steers reared on grass silage alone and not treated with growth promotants. Except for HCW (P < 0.01), the use of growth promotants did not affect carcass measurements. Increasing the proportion of barley in the diet of steers finished on forage produced a heavier HCW (P < 0.01) and a greater (P < 0.01) quality grade. Because of their lower HCW and quality grade, cattle targeted to a forage-fed, non implanted beef market would need to garner a 16% premium to be economically competitive with cattle finished conventionally.
(16-Oct-2006)
SUBJECTS: Animal Nutrition, Feeds and Feed technology, Meat science, Cattle
 

Dannenberger D, Nuernberg K, Nuernberg G, Ender K (2006) Carcass- and meat quality of pasture vs concentrate fed German Simmental and German Holstein bulls Archiv Fur Tierzucht-Archives of Animal Breeding 49 (4): 315-328 (in German)

KEYWORDS: German Holstein bulls; German Simmental bulls; pasture; carcass quality; meat quality; fatty acids; fatty-acid-composition; longissimus muscle; beef-cattle; intramuscular fat; feeding systems; hungarian-grey; friesian bulls; stearic-acid; steers; grass

SUMMARY: Many factors affect ruminant carcass and meat quality, and among the genetic and environmental factors, feeding plays an important role in the determination of quality. In a large study, sixty-four German Holstein and German Simmental bulls were randomly allocated to either an indoor concentrate feeding system or periods of pasture feeding following by a finishing period. During this period the animals got a concentrate containing linseed to improve the meat quality for the consumer and enhance the contents of beneficial fatty acids in beef German Simmental bulls grew faster in both feeding groups (concentrate and grass-based) compared to German Holstein bulls. Because of that significantly more days of fattening were necessary to reach the slaughter weight of 620 kg. The feeding system did not affect the carcass weights of both breeds. The results of cutting according to the regulations of the Deutsche Landwirtschafisgesellschaft (DLG-Schnittfuhrung fir die Zerlegung der Schlachtkorper von Rind, Kalb, Schwein und Schaf) showed diet effects for different cuts. Pasture feeding significantly decreased the weights of flank, flat ribs and brisket of both breeds. The intramuscular fat content of longissimus muscle was affected by the diet in the case of German Simmental bulls, only. The intramuscular fat content of longissimus muscle of pasture-fed German Simmental bulls was decreased to 1.5% compared with concentrate-fed bulls (2.6%). No diet effect was found in the intramuscular fat content of longissimus muscle of German Holstein bulls. The colour investigations of both muscles (longissimus and semitendinosus) showed that the beef produced by pasture feeding is darker. The Warner-Bratzler shear force values (WBSF) of pasture fed bulls were significantly higher compared to the concentrate fed bulls. Pasture feeding resulted in a significant increase in the concentration of n-3 fatty acids up to a factor of 2.8 in longissimus muscle of bulls compared with the concentrate feeding system.
(16-Oct-2006)
 

Sami AS, Koegel J, Eichinger H, Freudenreich P, Schwarz FJ (2006) Effects of the dietary energy source on meat quality and eating quality attributes and fatty acid profile of Simmental bulls Animal Research 55 (4): 287-299

KEYWORDS: energy; meat quality; fatty acid profile; Simmental bulls; conjugated linoleic-acid; concentrate-based diets; feeding intensity; carcass characteristics; intramuscular fat; grass-silage; beef-cattle; time; steers; starch

SUMMARY: Seventy-two Simmental bulls, weighing at the beginning of the experiment 408 +/- 24 kg, were fed fibrous or starch diets to a final weight of 622 +/- 34 kg. The animals were divided into three groups fed with the following: grass silage plus sugar beet pulp (GSS, n = 18) as a predominantly fibrous diet, maize silage plus wheat (MSW, n = 27) and maize silage plus corn (MSC, n = 27) as predominantly starch diets with different ruminal degradabilities of the starch. The dietary source of energy had no significant effects on the following meat characteristics: pH, colour, weight losses at ageing and grilling, grilling time and shear force values. These meat quality traits were also not affected by the dietary source of starch, rapid degradable (MSW) or slow degradable (MSC). In loin muscle steaks, sensory evaluation revealed no significant differences in tenderness and juiciness among the three groups. The steaks of the grass silage fed group (GSS) were rated lower for flavour than the steaks from the maize silage fed groups (MSW, MSC), with the difference between GSS and MSC being significant. The MSC group also had the highest intramuscular fat content with 1.96% ( P < 0.05). Feeding the GSS diet significantly increased the saturated fatty acids in the intramuscular and kidney fat compared to the MSW and MSC diets. Also, most polyunsaturated fatty acids especially n-3 fatty acids were increased by feeding the GSS diet. The MSC diet significantly reduced the PUFA in the intramuscular and kidney fat compared to the GSS diet. MUFA content was significantly higher when feeding starchy diets.
(16-Oct-2006)
 

Sampels S, Wiklund E, Pickova J (2006) Influence of diet on fatty acids and tocopherols in M. longissimus dorsi from reindeer Lipids 41 (5): 463-472

KEYWORDS: rangifer-tarandus-tarandus; adipose-tissue; lipid extraction; beta-carotene; human health; vitamin-e; muscle; meat; winter; stability

SUMMARY: Our aim was to compare the effects of two pelleted diets containing differing FA composition with natural lichen pasture on reindeer's meat FA composition. In addition we wanted to increase the knowledge about reindeer FA metabolism and the effect of animal sex and age on FA composition in reindeer muscle.
The trial included five reindeer groups: three grazing, consisting of adult males, adult females, and calves; and two groups of calves fed conventional pellets (CPD) and pellets containing crushed linseed (LPD), respectively, for two months before slaughter. Differences between male and female animals were mainly found in the neutral lipid fraction and related to fatness. Calves differed significantly from adult males and females in FA and lipid class composition. CPD led to a higher ratio of n-6 to n-3 FA compared with grazing. The ratio n-6/n-3 in the polar lipid (PL) fraction of the animals fed LPD was slightly, but not significantly, higher than that in the grazing reindeer. LPD-fed animals had lower proportions of long-chain polyunsaturated FA (LCPUFA), namely 20:4n-6, 22:5n-3, and 22:6n-3, in the PL fraction compared with the grazing animals due to the content of these FA in the natural feed. The animals seemed unable to elongate dietary FA in significant amounts. We conclude that by adding crushed linseed to the pellets it was possible to keep the favorable FA composition of meat from grazing reindeer with regard to the n-6/n-3 ratio but not in LCPUFA.
(16-Oct-2006)
 

Scollan N, Hocquette JF, Nuernberg K, Dannenberger D, Richardson I, Moloney A (2006) Innovations in beef production systems that enhance the nutritional and health value of beef lipids and their relationship with meat quality Meat Science 74 (1): 17-33

KEYWORDS: beef; nutrition; meat quality; fatty acids; health; conjugated linoleic-acid; polyunsaturated fatty-acids; retail packaged beef; blue young bulls; adipose-tissue; carcass characteristics; longissimus muscle; skeletal-muscles; color stability; aroma volatiles

SUMMARY: Consumers are becoming more aware of the relationships between diet and health and this has increased consumer interest in the nutritional value of foods. This is impacting on the demand for foods which contain functional components that play important roles in health maintenance and disease prevention. For beef, much attention has been given to lipids. This paper reviews strategies for increasing the content of beneficial omega-3 polyunsaturated fatty acids (PUFA) and conjugated linoleic acid (CLA) and reducing saturated fatty acids (SFA) in beef. Particular attention is given to intramuscular fat (IMF) and the relationships between fatty acid composition and key meat quality parameters including colour shelf life and sensory attributes. Despite the high levels of ruminal biohydrogenation of dietary PUFA, nutrition is the major route for increasing the content of beneficial fatty acids in beef. Feeding grass or concentrates containing linseed (rich in alpha-linolenic acid, 18:3n - 3) in the diet increases the content of 18:3n - 3 and its longer chain derivative eicosapentaenoic acid (EPA, 20:5n - 3) in beef muscle and adipose tissue, resulting in a lower n - 6:n - 3 ratio. Grass feeding also increases docasahexaenoic acid (DHA, 22:6n - 3). Feeding PUFA rich lipids which are protected from ruminal biohydrogenation result in further enhancement of the PUFA in meat with concomitant beneficial improvements in the ratio of polyunsaturated: saturated fatty acids (P:S ratio) and n - 6:n - 3 ratio. The main CLA isomer in beef is CLA cis-9, trans-11 and it is mainly associated with the triacylglycerol lipid fraction and therefore is positively correlated with level of fatness. The level of CLA cis-9, trans-11 in beef is related to (1) the amount of this isomer produced in the rumen and (2) synthesis in the tissue, by delta-9 desaturase, from ruminally produced trans vaccenic acid (18:1 trans-11; TVA). Feeding PUFA-rich diets increases the content of CLA cis-9, trans-11 in beef. Trans-fatty acids in foods are of rising importance and knowledge of the differential effects of the individual trans isomers is increasing. TVA is the major trans 18:1 isomer in beef and as the precursor for tissue CLA in both animals and man should be considered as a neutral or beneficial trans-isomer. Increasing the content of n - 3 PUFA in beef can influence colour shelf life and sensory attributes of the meat. As the content of n - 3 PUFA increases then sensory attributes such as "greasy" and "fishy" score higher and colour shelf life may be reduced. Under these situations, high levels of vitamin E are necessary to help stabilise the effects of incorporating high levels of long chain PUFA into meat. However, grass feeding not only increases n - 3 PUFA and CLA but, due to its high content of vitamin E, colour shelf life is improved. It is evident that opportunities exist to enhance the content of health promoting fatty acids in beef and beef products offering opportunities to add value and contribute to market differentiation. However, it is imperative that these approaches to deliver "functional" attributes do not compromise on the health value (lipoperoxidation) or the taste of beef products.
(16-Oct-2006)
 

Agnihotri MK, Rajkumar V, Dutta TK (2006) Effect of feeding complete rations with variable protein and energy levels prepared using by-products of pulses and oilseeds on carcass characteristics, meat and meat ball quality of goats Asian-Australasian Journal of Animal Sciences 19 (10): 1437-1449

KEYWORDS: goats; complete ration; carcass characteristics; meat balls and quality; chevon carcasses; performance; weight; muscle; growth; lambs; attributes; capretto; profiles; genotype

SUMMARY: Thirty six pre-weaned Barbari kids at 4 months age were reared on four rations computed using coarse cereal grains and by-products of pulses and oil seeds with Crude Protein (CP) and Total Digestible Nutrients JDN) of 12 and 55% (Low protein Low energy): 12 and 60% (Low protein High energy); 14 and 55% (High protein Low energy); and 14 and 60% (High protein High energy), respectively. After 180 days on feed, male animals (4x5 = 20) were slaughtered to study the effect of diet on carcass characteristics and meat quality. To asses the effect, if any, of such diet on product quality, meat balls were prepared and evaluated for quality changes when fresh as well as during storage (-20 +/- 1 degrees C). Feeding a ration with CP12 and TDN 60% (LH) to kids produced animals with highest slaughter weight (20.3 kg) yielding higher carcass weight and dressing percentage, lean (65.6%) and fat (6.6%) contents with low bone and trim losses. Although total variety meat yield was markedly higher in HL, the non-carcass fat deposition was relatively higher in LH carcasses. The water activity (aw) of fresh goat meat ranged from 0.994-0.995 and total cholesterol 72.8-90.5 mg/100 g meat. The pH was high in HL and HH meat resulting in decreased (p <= 0.05) extract release volume (ERV). Meat balls were prepared using meat obtained from goats fed different rations (treatments) and stored at -20 +/- 1 degrees C. They were evaluated on day 0 and months 1, 2, 3, 4 for physicochemical, microbiological and organoleptic changes. Overall moisture (%), aw , TBA number and pH value were 67.9, 0.987, 0.17 and 6.6 respectively and were not affected by treatments except pH that was significantly (p <= 0.01) lower on LH. As the storage period advanced moisture. pH, a. and TBA number increased irrespective of treatments. Feeding various diets had no marked effect on microbial load of meat balls but with increasing storage period Standard Plate Count (SPC) and psychrotrophs declined (p <= 0.01). Treatment LL and LH produced meat balls with better flavour.
(16-Oct-2006)
 

Siebert BD, Kruk ZA, Davis J, Pitchford WS, Harper GS, Bottema CDK (2006) Effect of low vitamin A status on fat deposition and fatty acid desaturation in beef cattle Lipids 41 (4): 365-370

KEYWORDS: adipose-tissue; retinoic acid; beta-carotene; differentiation; cleavage; jersey; goats; cells; liver; serum

SUMMARY: A group of Angus beef cattle was removed from temperate Pastures and fed a very low beta-carotene cereal-based ration in a feedlot for over 300 d. Half the group was supplemented weekly with retinyl palmitate (at the rate of 60,000 IU vitamin A/100 live weight (LW)/day), sufficient to offset clinical vitamin A deficiency; the other half received no supplement. Blood was sampled from all animals at biweekly intervals to assess carotene and vitamin A status. Adipose tissue was sampled by biopsy on three occasions throughout the experimental period and a slaughter to assess FA composition. Muscle was sampled at slaughter to determine the intramuscular fat content. The mean plasma concentration of beta-carotene of all g /mLmg/mL at 14 d, to 1.4 manimals fell from an initial value of 20.1 to 5.2  at 35 d, and to zero at 105 d. Mean vitamin A in plasma was not significantly different between the treatment groups initially. The values then rose to almost twice their initial values by 35 d, but subsequently fell to below initial values by day 119. Thereafter, plasma vitamin A of the supplemented group was significantly greater than that of the unsupplemented group (P < 0.05). Muscle samples at slaughter from supplemented animals contained significantly (P < 0.01) more intramuscular lipid (13.0 vs. 9.6%). Major changes occurred over time in FA composition in both groups. Saturated FA decreased as monounsatu rated FA increased over the first 60 d. An index of desaturation of FA was significantly lower (P < 0.001) in the vitamin A-supplemented group than in the non-supplemented group. M.P. of the adipose tissue of nonsupplemented animals was 32.3 degrees C, significantly less (P < 0.05) than that of supplemented animals (34.1 degrees C). Feeding vitamin A was associated with less (more ??) intramuscular fat but with a less desirable (less unsaturated, more solid) FA profile.
(16-Oct-2006)
 

Wasowska I, Maia MRG, Niedzwiedzka KM, Czauderna M, Ribeiro JMCR, Devillard E, Shingfield KJ, Wallace RJ (2006) Influence of fish oil on ruminal biohydrogenation of C18 unsaturated fatty acids British Journal of Nutrition 95 (6): 1199-1211

KEYWORDS: biohydrogenation; conjugated linoleic acid; fish oil; trans fatty acids; conjugated linoleic-acid; chromatography mass-spectrometry; lactating dairy-cows; bovine-milk; in-vitro; butyrivibrio-fibrisolvens; rumen bacteria; adipose-tissue; sunflower oil; dietary

SUMMARY: Dietary cis-9, trans-11-conjugated linoleic acid (CLA) is generally thought to be beneficial for human health. Fish oil added to ruminant diets increases the CLA concentration of milk and meat, an increase thought to arise from alterations in ruminal biohydrogenation of unsaturated fatty acids. To investigate the mechanism for this effect, in vitro incubations were carried out with ruminal digesta and the main biohydrogenating ruminal bacterium, Butyrivibrio fibrisolvens. Linoleic acid (LA) or alpha-linolenic acid (LNA) was incubated (1.67 g/l) with strained ruminal digesta from sheep receiving a 50:50 grass hay-concentrate ration. Adding fish oil (up to 4.17 g/l) tended to decrease the initial rate of LA (P=0.025) and LNA (P=0.137) disappearance, decreased (P < 0.05) the transient accumulation of conjugated isomers of both fatty acids, and increased (P < 0.05) the accumulation of trans-11-18:1. Concentrations of EPA (20:5n-3) or DHA (22:6n-3), the major fatty acids in fish oil, were low (100 mg/l or less) after incubation of fish oil with ruminal digesta. Addition of EPA or DHA (50 mg/l) to pure cultures inhibited the growth and isomerase activity of B. fibrisolvens, while fish oil had no effect. In contrast, similar concentrations of EPA and DHA had no effect on biohydrogenation of LA by mixed digesta, while the addition of LA prevented metabolism of EPA and DHA. Neither EPA nor DHA was metabolised by B. fibrisolvens in pure culture. Thus, fish oil inhibits ruminal biohydrogenation by a mechanism which can be interpreted partly, but not entirely, in terms of its effects on B. fibrisolvens.
(16-Oct-2006)
 

Alford AR, Hegarty RS, Parnell PF, Cacho OJ, Herd RM, Griffith GR (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 (6-7): 813-820

KEYWORDS: beef industry; greenhouse gas; feed effciency; residual feed intake; genetic-parameters; direct response; dairy-cows; cattle; growth; prediction; efficiency; selection; monensin; rumen

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 (N.B. Residual feed intake (RFI) is defined as actual feed intake minus the expected feed intake of an animal). 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 100t 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.
(16-Oct-2006)
 

Marino R, Albenzio M, Braghieri A, Muscio A, Sevi A (2006) Organic farming: effects of forage to concentrate ratio and ageing time on meat quality of Podolian young bulls Livestock Science 102 (1-2): 42-50

KEYWORDS: Podolian young bulls; forage to concentrate ratio; ageing time; tenderness; sensory properties; sensory properties; grass-silage; corn-silage; beef; grain; carcass; performance; color; pasture; regimen

SUMMARY: This study aimed to assess the effect of a different forage to concentrate ratio (60 to 40 (HC group) vs. 70 to 30 (LC group)) and ageing (15 vs. 21 days) on meat quality of Podolian young bulls, organically farmed. Longissimus dorsi was divided in two sections, aged in vacuum-packaging at 4 degrees C until 15 and 21 days postmortem, respectively. Meat chemical composition was unaffected by diet and ageing time. Colour parameters were not affected by diet, while red index a* and chroma decreased from 15 to 21 days of ageing, and yellow index and hue angle were found higher (P < 0.001) at 21 than at 15 days postmortem. The meat from the LC group showed lower (P < 0.01) Wamer-Bratzler shear force (ATSF) values than that from the HC group after 15 days of maturation. Extending ageing time from 15 to 21 days produced a significant (P < 0.001) reduction of WBSF. Diet effect on sensory tenderness was significant (P < 0.05) after 15 days of ageing with higher tenderness scores in the LC than in the HC group. Ageing positively affected sensory tenderness (P < 0.05) in the HC group. Flavour intensity was increased by the extension of the ageing period (P < 0.001), whereas no diet effect was evidenced on this parameter.
(16-Oct-2006)
 

Taweel HZ, Tas BM, Smit HJ, Elgersma A, Dijkstra J, Tamminga S (2006) Grazing behaviour, intake, rumen function and milk production of dairy cows offered Lolium perenne containing different levels of water-soluble carbohydrates Livestock Science 102 (1-2): 33-41

KEYWORDS: grazing behaviour; intake; rumen; water-soluble carbohydrate; tensile strength; sward surface height; herbage intake; dry-matter; n-alkanes; ryegrass; ruminants; performance; nutrition; allowance; protein

SUMMARY: The aim of this study was to assess grazing behaviour, intake, rumen function, milk production and composition of dairy cows grazing perennial ryegrass varieties that were morphologically and chemically similar, but differed in their water-soluble carbohydrate (WSC) concentration. Eight multiparous rumen cannulated dairy cows were offered four varieties of perennial ryegrass under a 1-day strip-grazing system using a 4 x 4 Latin square design in two consecutive years. Two of the varieties were characterised by a high WSC content (HSV) and the other two varieties had a lower concentration of WSC (LSV). Grazing behaviour was recorded using a solid-state behaviour recorder. Daily intake was estimated using the n-alkane technique. Rumen function was measured using rumen evacuation. As expected the HSV had a higher WSC content (P < 0.05) than the LSV with an average difference of approximately 32 g/kg dry matter. The other chemical constituents did not differ significantly between HSV and LSV The sward surface height, herbage allowance and tensile strength were not significantly different between HSV and LSV. None of the grazing behaviour parameters (eating time, rumination time, bite rate, chewing rate and bite mass) were significantly different between HSV and LSV Daily dry matter intake (DMI), fibre clearance rate, milk production and milk composition (fat, protein and lactose) were not different between cows grazing the HSV and LSV. At the level of difference in WSC content between the grass varieties reported in this study (32 g/kg), offering dairy cows a high sugar pasture did not influence grazing behaviour and rumen function and was not beneficial in improving DMI, milk yield or in altering the composition of milk.
(16-Oct-2006)
 

Bilby T. R., Block J., do Amaral B. C., Sa Filho O., Silvestre F. T., Hansen P. J., Staples C. R., Thatcher W. W. (2006) “Effects of Dietary Unsaturated Fatty Acids on Oocyte Quality and Follicular Development in Lactating Dairy Cows in Summer”. Journal of Dairy Science (89), 10 pp 3891-3903.

KEYWORDS: fatty acid, embryo, oocyte, cow.

SUMMARY: Dietary sources of fatty acids were evaluated for their influence on oocyte quality and follicular development using 54 lactating cows in summer. Fat supplements were 1) sunflower oil (80% cis 18:1), 2) Ca salt of transoctadecenoic acids (57% trans 18:1), 3) Ca salt of vegetable oils (30% 18:2), and 4) linseed oil (56% 18:3 and 16% 18:2). Fats were fed at 1.35% of dietary dry matter beginning at 5 wk prior to expected calving date and at 1.5% (oils) and 1.75% (Ca salts) of dietary dry matter for 15 wk after parturition. Four days following a programmed induced ovulation, 5 transvaginal oocyte aspirations were performed 3 or 4 d apart. Three days after the last aspiration, PGF2 was injected, followed 3 d later by a GnRH injection and a timed artificial insemination (d 0) 16 to 20 h later. For the first 4 aspirations, oocytes grading 1 or 2 were used for in vitro embryo production. Total cell number and the proportion of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)–positive blastomeres were analyzed at d 8. At the fifth aspiration, the occurrence of metaphase II, group II caspase activity, and TUNEL labeling were determined after oocyte maturation. A total of 1,011 oocytes were collected. The proportion of oocytes with high caspase activity was greater for grade 3 compared with grades 1 and 2 (37.5 vs. 1.54 and 1.61%). Feeding polyunsaturated fatty acids, as compared with monosaturated fatty acids, failed to affect oocyte quality, as demonstrated by subsequent embryo development. Cows fed 18:2- or 18:3-enriched diets had a larger preovulatory follicle at insemination and subsequent volume of the corpus luteum compared with those fed cis 18:1 or trans 18:1 diets (16.8, 16.2 vs. 15.0, 14.9 ± 0.7 mm; 7,323, 8,208 vs. 6,033, 5,495 ± 644 mm3, respectively). The previously documented benefits of polyunsaturated fatty acids on reproductive performance appear to reflect actions at alternative biological windows in lactating dairy cows.
(16-Oct-2006)

Patra A.K., Kamra D.N., Agarwal N. (2006) “Effect of plant extracts on in vitro methanogenesis, enzyme activities and fermentation of feed in rumen liquor of buffalo”. Animal Feed Science and Technology, (128), 3-4 pp 276-291.

KEYWORDS: Plant extracts, Methane, Rumen fermentation, Fibrolytic enzymes, Protozoa, Acacia concinna, Terminalia chebula, Terminalia belerica, Emblica officinalis, Azadirachta indica.

SUMMARY: The extracts of pods of Acacia concinna (Shikakai), seed pulp of Terminalia chebula (harad), Terminalia belerica (bahera), Emblica officinalis (amla) and seed kernel of Azadirachta indica (neem seed) in different solvents (ethanol, methanol and water) were evaluated for their effect on methane production, enzymes activities and rumen fermentation in in vitro gas production test. Gas production per gram dry matter (DM) of substrate (wheat straw and concentrate mixture in 1:1 ratio) was significantly (P<0.05) higher with extracts of A. concinna, E. officinalis and T. belerica as compared to control. Among the extracts tested only methanol extract of T. chebula suppressed in vitro methane production significantly (P<0.05). Specific activities of carboxymethylcellulase (CMCase) and xylanase were similar (P>0.05) among the extracts at both the levels tested, whereas, the activity of acetylesterase was reduced significantly (P<0.05). Total volatile fatty acids (TVFA) were significantly (P<0.05) decreased with extracts of T. chebula and A. indica. There was a decrease (P<0.05) in acetate to propionate ratio due to addition of the extracts of A. concinna and A. indica in incubation medium as compared to control. In vitro dry matter and organic matter degradabilities of feed (g/g) were decreased significantly (P<0.05) with all the extracts compared to that of control. The extracts of A. concinna and A. indica at 0.25 and 0.50 ml levels and extracts of T. chebula at 0.50 ml level reduced total protozoa counts significantly. Similar trends were observed for small and large entodiniomorphid protozoa counts. However, no effect (P>0.05) was found on holotrich protozoa numbers. The results indicated that methane emission is not essentially associated with protozoa activity since among three seed pulps with high antiprotozoal activity, only T. chebula (methanol extract) had antimethanogenic activity. The methanol extract of seed pulp of T. chebula appears to have a potential to be used for mitigation of enteric methane production, but the level of feeding will have to be evaluated so that there is minimum adverse effect on the degradability of feed in the rumen.
(21-July-2006)
 

Aoki M., Kimura K., Suzuki O. (2006) “Influence of feeding regime on timing of parturition in beef cattle and the relationship of vaginal temperature to parturition”. Animal Science Journal, (77), 3 pp 290-299.

KEYWORDS: beef cows, cosinor method, daytime parturition, night feeding, vaginal temperature.

SUMMARY: The timing of parturition was recorded for a total of 56 beef cattle (Japanese Black × Holstein Friesian) on different dietary treatments. The rate of calving during daylight hours in cows night-fed (18.00 hours) with a roughage diet was significantly higher than that in cows night-fed with a high concentrate diet (79.2% vs 38.5%, P < 0.05). Subsequently, the vaginal temperature (VT) of these cows was analyzed using a cosinor method. When the feeding schedule was changed from twice daily (08.30 and 15.30 hours) to night feeding, the periodicity, the acrophase and the bathyphase, which were the parameters of the cosine curve, were unstable from the first day of night feeding until after day 6 (P < 0.05). Prior to parturition, the midline-estimating statistic of rhythm (MESOR) and the amplitude for the cows that were fed a high-roughage diet at night and that calved at night-time were lower and larger, respectively, than that for the other treatments (P < 0.01). Based on these results, the time of parturition in most of the beef cows was influenced by feeding time and diet composition. Those cows that calved at night-time in spite of night feeding had lower vaginal temperatures.
(21-July-2006)
 

Ruiz TE, Febles G, Jordan H, Castillo E (2006) Legumes: their possibilities to implant sustainable cattle systems Cuban Journal of Agricultural Science 39: 485-497 Sp. Iss. SI, 2005

KEYWORDS: legumes; agronomy; milk yield; beef production; leucaena-leucocephala; animal performance; creeping legumes; feeding systems; beef-production; natural shade; stocking rate; in-vitro; pasture; protein

SUMMARY: This review analyzes and discusses alternatives or options related to agricultural systems in which tropical legumes (trees and creeping) are essential part of them and matters related to agronomy and milk and beef production. This review compiles data of the tropical area and that obtained in Cuba. Forms of decreasing the negative effects in the establishment of these species are indicated. Also, an important group of data is analyzed noting the real possibilities for the feeding of heifers, milk and beef production in these systems, as well as the possibility of substituting concentrates and fertilizers. The need for the special management of creeping legumes is noted to attain an adequate balance between them and the grass. The data provide sufficient scientific and technical elements that widen the existing concepts to achieve an adequate establishment and rangelands, stable and productive in a sustainable form. The studies should be continued for the obtainment of new integral technologies for the efficient exploitation of other tropical legumes.
(21-July-2006)
 

Lee SH, Park BY, Lee SS, Choi NJ, Lee JH, Yeo JM, Ha JK, Maeng WJ, Kim WY
(2006) Effects of spent composts of selenium-enriched mushroom and sodium selenite on plasma glutathione peroxidase activity and selenium deposition in finishing Hanwoo steers Asian-Australasian Journal of Animal Sciences 19 (7): 984-991

KEYWORDS: spent composts of Se-enriched mushroom; sodium selenite; glutathione peroxidase; selenium deposition; Hanwoo steers; dairy-cows; carcass characteristics; comparative metabolism; inorganic selenium; agaricus-bisporus; dietary selenium; tissue selenium; beef-cows; supplementation; performance

SUMMARY: Effects of spent composts of selenium-enriched mushroom (Se-SMC) on plasma glutathione peroxidase (GSH-Px) activity and selenium (Se) deposition in finishing Hanwoo (Bos taurus coreanae) steers were investigated. Twenty-five Hanwoo steers (average body weight = 613 kg, average age = 22 months) were allotted to treatments in five groups of five steers per pen for 12 weeks preceding slaughter. Treatments were SMC alone (CON; 0.1 ppm Se), 0.3 ppm (0.3 Se-SMC), 0.6 ppm (0.6 Se-SMC), 0.9 ppm (0.9 Se-SMC), and 0.9 ppm (sodium selenite; SENI) Se. During the experimental period, blood samples were taken to analyze Se concentrations and GSH-Px activities. Muscle and liver samples were collected for analyses of Se contents after slaughter. Dry matter intake and body weight gain were not affected by Se-SMC or sodium selenite supplementation. Selenium concentration in the whole blood and GSH-Px activity in plasma were linearly increased (p < 0.01) with increasing levels of Se-SMC. The whole blood Se concentration of SENI treatment was significantly higher (p < 0.05) than that of CON treatment from 4 weeks, whereas there was no significant difference in GSH-Px activities between both treatments at 8 and 12 weeks. Selenium content in the hind leg and liver increased linearly (p < 0.05) with increasing levels of Se-SMC, but those of SENI treatments were not significantly different from CON treatments.. These results suggested that Se in the Se-SMC was highly bioavailable to blood and tissues of ruminants, especially compared with Se in the sodium selenite Therefore, Se-SMC might be used not only as an inexpensive way of providing Se for ruminants but also as another way of producing Se-fortified beef.
(21-July-2006)
 

Williams CB, Bennett GL, Jenkins TG, Cundiff LV, Ferrell CL (2006) Using simulation models to predict feed intake: Phenotypic and genetic relationships between observed and predicted values in cattle Journal of Animal Science 84 (6): 1310-1316

KEYWORDS: cattle; feed intake; mathematical model; nutrient requirement; metabolizable energy-utilization; dynamic-model; beef-cattle; hereford cattle; mature cattle; efficiency; growth; traits; performance; heterosis

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 (CFRmcp, CFRmc, CFRg, CFRmg, and CFRm, respectively) and DECI (DFRmcg, DFRmc, DFRg, DFRmp, 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 (s(y.x)) = 0.669 kg/d] and OFI = 1.32 (SE = 0.22) + 0.8 (SE = 0.03) x DFRmcg (R2 = 0.53, s(y.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 CFRmcp, CFG(mg,) 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.
(21-July-2006)
 

Cho YM, Choi H, Hwang IH, Kim YK, Myung KH (2006) Effects of 25-hydroxyvitamin D-3 and manipulated dietary cation-anion difference on the tenderness of beef from cull native Korean cows Journal of Animal Science 84 (6): 1481-1488

KEYWORDS: anion; beef; calcium; 25-hydroxyvitamin D-3; tenderness; vitamin-D-3 supplementation; longissimus tenderness; dairy-cows; calcium; steers; metabolites; calpain

SUMMARY: In this study, we characterized the effects of 25-hydroxyvitamin D-3 (25-OH D-3) and manipulated dietary cation-anion difference (DCAD) on the performance, urine pH, serum constituents, carcass traits, tissue residual vitamin D and its metabolites, beef tenderness, and mRNA and protein concentrations of Ca-dependent proteinases in LM using 24 cull native Korean cows. The cows were divided into 3 groups of 8: control, 25-OH D-3 supplemented (25-OH D-3), and manipulated DCAD plus 25-OH D-3 supplemented (DCAD+25-OH D-3).Cows receiving 25-OH D-3 or DCAD+25-OH D-3 were dosed with 125 mg of 25-OH D-3 6 d before slaughter. The manipulated DCAD (-10 mEq/ 100 g of DM) diet was fed from 20 to 6 d (14 d) before slaughter. The DCAD+25-OH D-3 treatment decreased urine pH and increased serum Ca concentrations. Although the vitamin D concentrations in LM, liver, and kidney were not affected by 25-OH D-3 or DCAD+25OH D3, muscle tissue 25-OH D-3 concentrations were increased by both regimens. Serum 25-OH D-3 concentrations were increased by 25-OH D-3 supplementation, and the increase was even greater for DCAD+25-OH D-3. The same pattern was observed for serum 1,25(OH)2 D-3. However, the LM concentration of 1,25-(OH)(2) D-3 was less for DCAD+25-OH D-3 than for control. Although Ca concentrations of LM increased numerically in response to 25-OH D-3 supplementation, no statistical differences in Warner-Bratzler shear force or sensory traits of LM were detected. The LM of cows receiving 25-OH D-3 with or -calpain and m-calpainmwithout manipulated DCAD had greater concentrations of  mRNA, whereas the reverse was observed for calpastatin mRNA. Expression of -calpain protein was increased relative to control by DCAD+25-OH D-3. Them amount of 25-OH D-3 and manipulated DCAD administered to cull native Korean cows was insufficient to improve tenderness of beef by increasing muscle Ca -calpainmconcentration. However, DCAD+25-OH D-3 induced greater expressions of  protein as well as mRNA.
(21-July-2006)
 

Beauchemin KA, McGinn SM (2006) Methane emissions from beef cattle: Effects of fumaric acid, essential oil, and canola oil Journal of Animal Science 84 (6): 1489-1496

KEYWORDS: beef cattle; canola oil; essential oil; fumaric acid; greenhouse gas; methane; microorganisms in-vitro; ruminal microorganisms; fermentation; protozoa

SUMMARY: The objective of this study was to identify feed additives that reduce enteric methane emissions from cattle. We measured methane emissions, total tract digestibility (using chromic oxide), and ruminal fermentation (4 h after feeding) in growing beef cattle fed a diet supplemented with various additives. The experiment was designed as a replicated 4 x 4 Latin square with 21-d periods and was conducted using 16 Angus heifers (initial BW of 260 32 kg). Treatments were: control (no additive), fumaric acid (175 g/d) with sodium bicarbonate (75 g/d), essential oil and spice extract (1 g/d), or canola oil (4.6% of DMI). The basal diet consisted of 75% whole-crop barley silage, 19% steamrolled barley, and 6% supplement (DM basis). Four large chambers (2 animals fed the same diet per chamber) were equipped to measure methane emissions for 3 d each period. Adding canola oil to the diet decreased (P = 0.009) total daily methane emissions by 32% and tended (P = 0.09) to decrease methane emissions as a percentage of gross energy intake by 21%. However, much of the reduction in methane emissions was due to decreased (P < 0.05) feed intake and lower (P < 0.05) total tract digestibility of DM and fiber. Digestibility of all nutrients was also lowered (P < 0.05) by feeding essential oil, but there were no effects on ruminal fermentation or methane emissions. In contrast, adding fumaric acid to the diet increased total VFA concentration (P = 0.03), increased propionate proportions (P = 0.01), and decreased the acetate:propionate ratio (P = 0.002), but there was no measurable effect on methane emissions. The study demonstrates that canola oil can be used to reduce methane losses from cattle, but animal performance may be compromised due to lower feed intake and decreased fiber digestibility. Essential oils had no effect on methane emissions, whereas fumaric acid caused potentially beneficial changes in ruminal fermentation but no measurable reductions in methane emissions.
(21-July-2006)
 

Cavalcante MAB, Pereira OG, Valadares SDC, Rlbeiro KG, Pacheco LBB, Araujo D, Lemos VMC (2006) Crude protein levels on beef cattle diets: ruminal metabolism, nitrogen balance, and microbial protein synthesis Revista Brasileira de Zootecnia-Brazilian Journal of Animal Science 35 (1): 203-210 (in Portuguese)

KEYWORDS: microbial efficiency; ammonia nitrogen; ruminal pH; passage rate;
fiber digestion; invitro; spectrophotometry; digestibility; availability; carbohydrate; ammonia; samples; system; flow

SUMMARY: The objective of this trial was to investigate the effects of different dietary crude protein levels (10.5, 12, 13.5, and 15%) on ruminal pH, ruminal concentration of ammonia nitrogen, ruminal passage rate, nitrogen balance, and microbial protein synthesis in Holstein x Zebu steers. Diets contained 65% of Tifton 85 bermudagrass hay and 35% of concentrate. Four castrated steers averaging 487.3 kg of initial body weight and fitted with ruminal and abomasal carmulas were randomly assigned to a 4 x 4 Latin square design. Each experimental period lasted 20 days with 10 days for diet adaptation and 10 days for sample collection. Ruminal fluid was collected before (0 h) and at 2, 4, 6 and 8 h after feeding for determination of both ruminal pH and ammonia-N. Ruminal passage rate was determined according to a unicompartmental model using chromic oxide as the external marker while abomasal purine bases (RNA) were used as the internal markers for measuring microbial protein synthesis. Ruminal pH and ammonia-N concentration were affected by sampling time with measured maximum values of 6.54 and 17.43 mg/dL at 3.62 and 4.17 h after feeding, respectively. Digesta passage rate did not differ significantly averaging 3.69 %/h across diets. Similarly, abomasal flow of N compounds as well as microbial efficiency were not affected by different dietary crude protein levels while nitrogen balance expressed in g/day increased linearly when the crude protein content increased from 10.5% to 15% in the diet.
(21-July-2006)
 

Mendes AR, Ezequiel JMB, Galati RL, Do Nascimento VF, Queiroz MAA, de Pereira EMO (2006) Digestion kinetics and efficiency of microbial protein synthesis on beef steers fed sunflower meal and different energy sources Revista Brasileira de Zootecnia-Brazilian Journal Of Animal Science 35 (1): 264-274 (in Portuguese)

KEYWORDS: corn germ meal; dilution rate; ruminal microbial; passage rate; soybean hulls;
different concentrate levels; soybean hulls; dairy-cows; fed diets; passage; digestibility; quality; hay; bacteria; markers

SUMMARY: The objective of this trial was to evaluate the partial replacement of ground corn with soybean hulls or corn germ meal on ruminal microbial protein synthesis and efficiency and ruminal dilution and passage rates. Three crossbreed steers fitted with ruminal and duodenal cannulas were assigned to two 3 x 3 Latin squares. The experimental diets contained: corn silage (60%), sunflower meal and ground corn (GC diet) that was partially replaced with soybean hulls (SBH diet) or corn germ meal (CGM diet). Ruminal fluid was collected at 3, 6, 9, and 12 hours after feeding for isolation of ruminal microbes. RNA was used as the microbial marker while sodium dicromate and Co-EDTA were used as passage and dilution rate markers, respectively. Ruminal microbial composition was not affected by diets and time after feeding in the present trial. Moreover, duodenal flows of organic matter, total carbohydrates, nitrogen (N), and microbial N as well as microbial efficiency were all not significantly changed across diets. Fluid dilution rate also did not differ and averaged 13.4%/h among diets. Ruminal passage rate of mordant corn silage was lower and a trend for lower passage rate of sunflower meal on GC diet also was observed. Soybean hulls and corn germ meal can partially replace ground corn on diets for confined steers because they provided adequate ruminal environment for microbial growth and microbial protein synthesis.
(21-July-2006)
 

Foster JG, Clapham WM, Fedders JM (2006) Quantification of fatty acids in forages by near-infrared reflectance spectroscopy Journal of Agricultural and Food Chemistry 54 (9): 3186-3192

KEYWORDS: near-infrared reflectance spectroscopy; forage; lauric acid; linoleic acid; alpha-linolenic acid; myristic acid; palmitic acid; palmitoleic acid; oleic acid; stearic acid; conjugated linoleic-acid; brassica-napus l.; calibration equations; oil content; intramuscular fat; nutritive-value; beef-cattle; seed oil; quality; diets

SUMMARY: Near-infrared reflectance spectroscopy (NIRS) was evaluated as a possible alternative to gas chromatography (GC) for the quantitative analysis of fatty acids in forages. Herbage samples from 11 greenhouse-grown forage species ( grasses, legumes, and forbs) were collected at three stages of growth. Samples were freeze-dried, ground, and analyzed by GC and NIRS techniques. Half of the 195 samples were used to develop an NIRS calibration file for each of eight fatty acids, with the remaining half used as a validation data set. Spectral data, collected over a wavelength range of 1100-2498 nm, were regressed against GC data to develop calibration equations for lauric (C12:0), myristic (C14:0), palmitic (C16:0), stearic (C18:0), palmitoleic ( C16: 1), oleic (C18: 1), linoleic (C18: 2), and alpha-linolenic ( =C18: 3) acids. Calibration equations had high coefficients of determination for calibration (0.93-0.99) and cross-validation (0.89-0.98), and standard errors of calibration and cross-validation were < 20% of the respective means. Simple linear regressions of NIRS results against GC data for the validation data set had r(2) values ranging from 0.86 to 0.97. Regression slopes for C12: 0, C14: 0, C16: 0, C18: 0, C16: 1, C18: 2, and C18: 3 were not significantly different ( P = 0.05) from 1.0. The regression slope for C18: 1 was 1.1. The ratio of standard error of prediction to standard deviation was > 3.0 for all fatty acids except C12: 0 (2.6) and C14: 0 (2.9). Validation statistics indicate that NIRS has high prediction ability for fatty acids in forages. Calibration equations developed using data for all plant materials accurately predicted concentrations of C16: 0, C18: 2, and C18: 3 in individual plant species. Accuracy of prediction was less, but acceptable, for fatty acids (C12: 0, C14: 0, C18: 0, C16: 1, and C18: 1) that were less prevalent.
(21-July-2006)
 

Agenas S, Heath MF, Nixon RM, Wilkinson JM, Phillips CJC (2006) Indicators of undernutrition in cattle Animal Welfare 15 (2): 149-160

KEYWORDS: albumin; animal welfare; cattle; fructosamine; plasma metabolites; undernutrition; lactating dairy-cows; serum fructosamine; feed-intake; milk-production; energy-balance; weight changes; fatty-acids; dry period; beef-cows; plasma

SUMMARY: Potential biochemical indicators of long-term undernutrition in cattle, which could be used objectively, reliably and routinely, were investigated by evaluating frequently analysed metabolites in cattle. In an initial study, a meta-regression of literature data for glucose, urea, non-esterified fatty acids (NEFA) and beta-hydroxybutyrate (BHB) against body condition score (BCS), body weight (BW) and its change (BWC) was conducted. The credible intervals of the gradients included zero for all regressions, showing that there were no significant relationships between any of the blood metabolites and BCS, BW or BWC across the 13 included studies. In a second study, fresh field samples from nine herds of adequately-nourished suckler cows and stored samples from two herds of suckler cows, which had experienced severe undernutrition, were analysed for serum albumin, total protein, urea, BHB, NEFA, creatinine, fructosomine and globulin. Positive regressions with BCS were obtained for albumin and creatinine, and a negative regression with fructosamine/albumin ratio. With the threshold for detecting undernutrition set at >= 10.75 mu mol g(-1), the fructosamine/albumin ratio gave sensitivity and specificity of 100%. Therefore, it is probably necessary to combine several blood measures to obtain a valid assessment of the nutritional state of ruminants, and we advise against the use of a single plasma metabolite concentration in assessing the nutritional state and welfare of individual cows.
(21-July-2006)
 

Machmuller A, Ossowski DA, Kreuzer M (2006) Effect of fat supplementation on nitrogen utilisation of lambs and nitrogen emission from their manure Livestock Science 101 (1-3): 159-168

KEYWORDS: ruminants; lipids; oilseeds; coconut oil; N utilisation; ammonia emission;
fermentation in-vitro; dairy-cows; rumen fermentation; ammonia emission; methane release; plant-extracts; fed diets; metabolism; protein; digestion

SUMMARY: The effects of various fats on nitrogen digestion and metabolism of lambs and their manure were investigated in six isoenergetic diets (n = 6) with similar contents of absorbable protein. Treatments were either a control diet or diets containing 25 g/kg of additional ether extract from rumen-protected fat, coconut oil, rapeseed, sunflower seed or linseed. Fat supplementation resulted in trends for higher apparent nitrogen digestibilities (significant with coconut oil; P < 0.05, post hoc test) and body nitrogen retention (P < 0.1). Urinary nitrogen losses and their proportion of manure nitrogen did not differ significantly among groups as was also true for C/N ratio, dry matter, nitrogen and ammonia nitrogen contents of the manure. In the first week of manure storage, most fat supplements tended to decrease gaseous nitrogen emission as assessed by respiration chamber and mass balance measurements. These differences tended to be mitigated after 7 weeks of manure storage. Only the coconut-oil treatment still resulted in numerically lower nitrogen emissions. In conclusion, addition of fat source in the diet, in addition to increasing dietary energy and suppressing methanogenesis, can under certain circumstances decrease gaseous nitrogen emission from the manure.
(21-July-2006)
 

Mishra S, Thakur SS, Tyagi N (2006) Effect of different forms of mustard oil supplementation on in vitro dry matter, cell wall degradability, gas production and biohydrogenation of unsaturated C-18 fatty acids Indian Journal of Animal Sciences 76 (5): 398-404

KEYWORDS: animal nutrition; biohydrogenation; fibre degradation; mustard oil; rumen protected fat; calcium soaps; dairy-cows; rumen; digestibility; fermentation; metabolism; duodenum; invitro; flow

SUMMARY: Mustard oil, in 4 different forms, viz. mustard oil (MO), crushed mustard seeds (MS), crushed and heat treated mustard seeds (MSH) and calcium salts of mustard oil fatty acids (CS), each added in basal substrate (60:40, wheat straw: concentrate mixture), to attain 5 different levels (2,4,6,8 and 10% of supplemental mustard oil) were investigated for their effect on in vitro DM and cell wall degradability, gas production and biohydrogenation of C-18 fatty acids. Ether extract content in concentrate Mixtures ranged from 7.58 to 30.76% in MO, 8.07 to 29.72% in MS, 7.88 to 29.43% in MSH and 7.07 to 28.26 in CS. Mean IVDMD (%) at 48h was highest in CS (55.64), followed by MO (53.62) and the lowest in MS and MSH (51.71 and 51.64). In vitro gas production (ml/0.5g/24h) was the highest in MS (56.64), followed by MO (48.41), MSH (36.97) and CS (33.70). Similar trend was observed for gas production at 48h. Methane production (%) was the highest in MO, followed by MS, MSH and CS. In vitro NDF and ADF degradability decreased with increasing levels of supplemental fat more specifically in MO and MS containing mustard oil as such and crushed mustard seeds. Total gas production, methane production and mean IVDMD were the highest at 2% level and lowest at 10% supplementation level. In vitro biohydrogenation (%) of total unsaturated C,, fatty acids was the lowest in CS containing Ca salts of mustard oil fatty acids (58.44%), followed by MSH and MS (77.38, 84.28) and the highest in MO group (91.08). Similar trend was observed for biohydrogenation of individual C-18:1, C-18.2 and C-18.3 acids. Thus, it could be concluded from the present study that conversion of mustard oil fatty acids into its calcium salts was the most effective method of protecting them from rumen hydrolysis as was evident from improved IVDMD, cell wall degradability and reduced biohydrogenation.
(21-July-2006)
 

Ungerfeld EM, Rust SR, Burnett R (2006) Effects of butyrate precursors on electron relocation when methanogenesis is inhibited in ruminal mixed cultures Letters in Applied Microbiology 42 (6): 567-572

KEYWORDS: butyrate; electron acceptors; fermentation; inhibition; methane; rumen; rumen microorganisms; amino-acids; fermentation; digestion; cattle

SUMMARY: Aims: Inhibition of ruminal methanogenesis often causes accumulation of H-2, formate and ethanol, which are not energy substrates for ruminants. It was hypothesized that the addition of butyrate precursors would avoid the formation of these products and relocate electrons into butyrate. Methods and Results: In four ruminal 24-h incubations, two inhibitors of methanogenesis, each at three different initial concentrations (0, 2 or 4 mmol l(-1) for propynoic acid, and 0, 4 or 8 mmol l(-1) for ethyl 2-butynoate), were combined with two butyrate precursors at two different initial concentrations (0 or 4 mmol l(-1) for crotonic acid or 3-butenoic acid). Ground lucerne hay was the substrate. Propynoic acid at 4 mmol l(-1) decreased CH4 formation by more than two-thirds. Ethyl 2-butynoate at 8 mmol l(-1) suppressed methanogenesis by more than 90%. Butyrate precursors generally did not decrease the accumulation of H-2 and formate or ethanol production. Conclusions: Butyrate precursors were ineffective as electron acceptors because they were not completely converted to butyrate and were also metabolized through other pathways. Significance and Impact of the Study: Effectiveness of butyrate precursors may be improved by adding them to the fermentation continuously or by enhancing the kinetics of their conversion into butyrate.
(21-July-2006)
 

Dalmau A, Ferret A, Manteca X, Calsamiglia S (2006) In vitro ruminal fermentation using inoculum from chamois and cattle Rangeland Ecology & Management 59 (3): 293-299

KEYWORDS: dual-flow continuous culture; fermentation profile; nitrogen metabolism; nitrogen-utilization; voluntary intake; sheep; protein; rumen; goats; digestibility; digestion; protozoa; ammonia

SUMMARY: Six dual-flow continuous culture fermenters were used over a 10-day experimental period to compare the digestibilities of dry matter (DM) and fiber, ruminal fermentation profile, and nitrogen metabolism of rumen microbial populations obtained from an inoculum of chamois (Rupicapra pyrenaica pyrenaica) and cattle (Bos taurus). The aim of this work was to test the fermenters with inoculum from chamois and to compare the function of ruminal microbial population of chamois and cattle under the same conditions of diet and passage rate. Fermenters were fed 56 g DM daily of a diet consisting of 75% Italian ryegrass hay (Lolium multiflorum Lam. var. westerwoldicum) and 25% alfalfa hay (Medicago sativa L.). Both inocula were adapted to the in vitro conditions after 6 days. There were no differences in DM and fiber digestibilities, and total volatile fatty acids concentration (VFA) between cattle and chamois inocula. The proportion of propionate was higher (25.8 vs. 17.9 mol/100 mol), and that of butyrate was lower (9.9 vs. 13.8 mol/100 mol) in chamois inoculum than in cattle inoculum. Ammonia nitrogen concentration was greater (10.6 vs. 6.7 mg/100 ml), but microbial protein synthesis was lower (41.1 vs. 55.3% of total nitrogen flow) in chamois inoculum than in cattle inoculum. These results suggest that microbial populations from chamois and cattle inocula, maintained under the same conditions of diet and passage rate, have a similar degradation capacity, producing the same amounts of VFA, but with a different fermentation profile, and different microbial protein synthesis. The dual-flow continuous culture fermenters could be a useful tool to study ruminal fermentation in wild species such as Pyrenean chamois.
(21-July-2006)
 

Seo S, Tedeschi LO, Lanzas C, Schwab CG, Fox DG (2006) Development and evaluation of empirical equations to predict feed passage rate in cattle Animal Feed Science and Technology 128 (1-2): 67-83

KEYWORDS: passage rate; meta-analysis; empirical model; model comparison; CNCPS; intragastric infusions; mechanistic model; water kinetics; particle-size; dairy-cows; rumen; sheep; digestibility; requirements; parameters

SUMMARY: Empirical equations were developed to accurately predict passage rate (K) in ration formulation models for all classes of dairy and beef cattle. The database was comprised of studies that used external markers, and 553, 195 and 766 treatment means were used to develop the K equations for forages, concentrates and liquid, respectively. A random coefficients model that used each study effect as a random variable was used to select statistically significant input variables to predict rate of passage. The parameters of the variables were estimated using ordinary least square method. The equations developed were: K-p forage = (2.365 + 0.0214FpBW + 0.0734CpBW + 0.069FDMI)/100; K-p concentrate = (1.169 + 0.1375FpBW + 0.1721CpBW)/100 and K-p liquid = (4.524 + 0.0223FpBW + 0.2046CpBW + 0.344FDMI)/100, where K-p is the passage rate, h(-1); FpBW the forage DMI as a proportion of BW, g/kg; CpBW the concentrate DMI as a proportion of BW and FDMI is the forage DMI, g/kg These K-p equations for forages, concentrates and liquid explained 87%, 95% and 94%, respectively of the variation in passage rates in the database used in equation development after adjustment for random study effect. These and other published equations were evaluated with an independent database. In this evaluation, the R2 of the new equations were 0.39, 0.40 and 0.25 for prediction of the passage of forages, concentrates and liquid, respectively, which was higher than the R2 of the previously published equations by 0.03-0.19, 0.01-0.14, and 0.04-0.16 for forages, concentrates and liquid, respectively. The root mean square prediction error (RMSPE) was reduced by 3-22%, 2-33%, and 4-31% in the prediction of K-p of forages, concentrates and liquid, respectively, with the new equations. These new empirical equations are suitable for predicting passage rate in cattle, but predictability overall is still low and increases in the accuracy of predicting passage rates requires development of a mechanistic model that accounts for more biologically important variables affecting passage rate (e.g. physical property of particles, water intake and flux, and within day variation in intake).
(21-July-2006)
 

Maddock TD, Bauer ML, Koch KB, Anderson VL, Maddock RJ, Barcelo-Cobijn G, Murphy EJ, Lardy GP (2006) Effect of processing flax in beef feedlot diets on performance, carcass characteristics, and trained sensory panel ratings Journal of Animal Science 84 (6): 1544-1551

KEYWORDS: beef cattle; fatty acid; finishing; flax; processing; sensory characteristic; polyunsaturated fatty-acids; comparative feeding value; supplemental fat; finishing diets; cattle performance; adipose-tissue; tallow level; meat quality; steers; traits

SUMMARY: To assess the effects of flax addition and flax processing on feedlot performance and carcass characteristics, 128 yearling beef heifers (360 14 kg of initial BW) were blocked by weight and assigned randomly to feedlot diets that included no flax (control), whole flax (WHL), rolled flax (RLD; 1,300 mu m), or ground flax (GRD; 700 mu m). Heifers were fed a growth diet (31% corn, 30% corn silage, 18% barley malt pellets, 14% alfalfa, 4% linseed meal, and 3% supplement; DM basis) for 56 d, after which they were adapted to a finishing diet (79% corn, 7% corn silage, 7% alfalfa, 4.75% linseed meal, and 2.25% supplement; DM basis). In WHL, RLD, and GRD, flax replaced all linseed meal and partially replaced corn at 8% of diet DM. All diets provided 0.5 mg of melengestrol acetate, 2,000 IU of vitamin E, and 232 mg of monensin per heifer daily. Cattle were slaughtered by block after 96, 97, and 124 (2 blocks) d on feed. At 24 h postmortem, carcass data were collected, and a portion of the loin was removed, vacuum-packaged, and aged for 14 d. After aging, 2 steaks were removed from each loin for Warner-Bratzler shear force measurement, sensory panel evaluation, and fatty acid analysis (approximately 100 g of muscle was collected). Flax inclusion (WHL, RLD, and GRD vs. control) did not affect DMI (P = 0.79), fat thickness over the 12th rib (P = 0.32), or LM area (P = 0.23). Flax inclusion increased ADG (P = 0.006), G:F (P = 0.006), and USDA yield grade (P = 0.01). Flax processing (RLD and GRD vs. WHL) increased ADG (P = 0.05), GY (P = 0.08), and apparent dietary NE.. and NEg (P = 0.003). Muscle from heifers fed flax had greater phospholipid 18:3n-3 (P < 0.001), 20:5n-3 (P < 0.001), 22:5n-3 (P < 0.001), and 22:6n-3 (P = 0.02) fractions, and greater neutral lipid 18:3n-3 (P < 0.001). Feeding 8% flax to feedlot heifers increased gain and efficiency, and processing flax increased available energy and resulted in increased efficiency of gain. Feeding 8% flax also increased levels of n-3 fatty acids in fresh beef.
(21-July-2006)
SUBJECTS: Animal Nutrition, Feeds and Feed Technology, Meat science, Quality Products and Organic Production, Cattle
 

Keren EN, Olson BE (2006) Thermal balance of cattle grazing winter range: Model application Journal of Animal Science 84 (5): 1238-1247

KEYWORDS: beef cattle; metabolic requirement; orientation; simulation model; solar radiation; winter; seasonal energy expenditures; resting heat-production; thermoregulatory responses; body-temperature; solar-radiation; beef-cattle; requirements; environment; altitude; coats

SUMMARY: Beef cattle grazing semiarid foothill rangeland of the Northern Rockies during winter may be exposed to cold temperatures and high winds while grazing pastures with low nutritional value. Cattle can physiologically and behaviorally respond to the changing environment to lower their metabolic requirements and reduce the effects of cold exposure. Requirements of grazing cattle may be overpredicted with models developed in controlled settings that do not account for energy-conserving behaviors. We refined a simple thermal balance equation to model heat exchange of free-ranging cattle. We accounted for the complex interactions between animal behavior and the changing natural environment by applying the insulation characteristics of the cattle's tissue and coat to a simple geometric shape of an asymmetric ellipsoid at different orientations to the sun and wind. We compared the model predictions with heat production measured in 3 studies, and in all cases the model predictions were similar to those reported. Model simulations indicate behaviors, such as lying and orientation to the sun, mitigated the effects of extreme weather. For many combinations of winter weather variables, metabolic requirements increased only slightly due to cold. Exposure of mature beef cattle in a near-maintenance state. The results indicate that solar radiation contributes strongly to the thermal balance of a cow. Thus, previous models that do not account for the irradiative environment may overestimate metabolic requirements of cattle acclimated to grazing winter range.
(21-July-2006)
 

Basarab JA, Okine EK, Baron VS, Marx T, Ramsey P, Ziegler K, Lyle K (2006) Methane emissions from enteric fermentation in Alberta's beef cattle population Canadian Journal of Animal Science 85 (4): 501-512

KEYWORDS: cattle; enteric fermentation; greenhouse gas; methane; tracer gas technique; pasture; cows; requirements; prediction; ruminants; heifers; dietary; growth; steers

SUMMARY: This study determined methane emissions from enteric fermentation in Alberta's beef cattle population by using three methodologies: (1) Intergovernmental Panel on Climate Change (IPCC), Tier 2 guidelines for cattle, (2) actual methane emission factors, expressed as a percentage of gross energy intake, from Canadian research trials and; (3) CowBytes (c) plus the basic equation developed by Blaxter and Clapperton (1965). Methane emissions, in carbon dioxide equivalents (CO2-E), from Alberta's beef cattle were determined for 1990, 1996 and 2001. Census of Agriculture numbers for Alberta (Statistics Canada; www.statcan.com) were used and beef cattle were subdivided into 31 distinct categories based on animal type, physiological status, gender, weight, growth rate, activity level and age. Emission of greenhouse gases (GHG) from Alberta's beef cattle population, based on IPCC Tier 2 guidelines, were 4.93, 6.57 and 7.01 Mt CO2-E yr(-1) in 1990, 1996 and 2001, respectively. Emissions based on methane emission factors from Canadian research trials were 6.23, 8.26 and 8.77 Mt CO2-E yr(-1) in 1990, 1996 and 2001, respectively. Estimated methane emissions based on CowBytes (c) and Blaxter and Clapperton's (1965) equation were 6.24, 8.35 and 8.94 Mt CO2-E yr(-1) in 1990, 1996 and 2001, respectively. The IPCC Tier 2 values were 25.2-26.5% lower than the GHG emissions calculated using emission factors from western Canadian research and 26.7-27.6% lower than GHG emissions calculated from CowBytes (c) and Blaxter and Clapperton's equation. IPCC Tier 1 values, which were calculated by multiplying total beef cattle in Alberta by four single value emission factors (beef cows = 72 kg CH4 yr(-1); bulls = 75 kg CH4 yr(-1); replacement heifers = 56 kg CH4 yr(-1); calves, steer and heifer calves for slaughter = 47 kg CH4 yr(-1)), were 4.83, 6.40 and 6.83 Mt CO2-E in 1990, 1996 and 2001, respectively. Thus, IPCC Tier 1 GHG emissions from enteric fermentation in beef cattle were 2.0-2.7, 28.6-29.1 and 29.2-31.0% lower than those calculated from IPCC Tier 2, western Canadian research trials, and CowBytes (c) plus Blaxter and Clapperton's equation, respectively. These results reflect the uncertainty associated with estimating methane emissions from enteric fermentation in cattle and suggest that further research is required to improve the accuracy of methane emissions, particularly for beef cows in their second and third trimester of pregnancy and fed in confinement. They also indicate that a more robust methodology may be to combine CowBytes (c) predicted dry matter intake with regional specific methane emission factors, where methane loss is expressed as a percentage of gross energy intake.
(21-July-2006)
 

Leroy JLMR, Vanholder T, Opsomer G, Van Soom A, Bols PEJ, Bossaert P, de Kruif A (2006) Typical metabolic changes in high producing dairy cows early postpartum and their consequences on oocyte and embryo quality Vlaams Diergeneeskundig Tijdschrift 75 (2a): 94-104 Sp. Iss. Si

KEYWORDS: nonesterified-fatty-acids; in-vitro maturation; follicular-fluid; bovine-oocytes; granulosa-cells; energy-balance; messenger-rna; milk-yield; developmental competence; ionic composition

SUMMARY: The negative energy balance (NEB) is characterized by typical biochemical changes such as high non-esterified fatty acid (NEFA), high beta-hydroxybutyrate (BHB) and low glucose concentrations. The concentrations of these metabolites were extensively analyzed in the follicular fluid of high yielding dairy cows during NEB and were imitated in in vitro maturation models to investigate their effects on oocyte quality. The studies reviewed in this paper showed that the typical metabolic changes that occur during NEB are well reflected in the follicular fluid (FF) of the dominant follicle. However, the oocyte seems to be relatively isolated from excessively high NEFA or excessively low glucose concentrations in the blood. Nevertheless, the in vitro maturation models revealed that such metabolic changes in the FF associated with a NEB (high NEFA and low glucose concentrations) are indeed toxic for the oocyte, resulting in hampered oocyte maturation, increased apoptosis and necrosis in the cumulus cells, and jeopardized developmental competence of the resulting embryos. Only in moderately hypoglycemic maturation conditions did BHB have an additive toxic effect. These in vitro maturation models, based on in vivo observations and reviewed in this paper, suggest that a period of NEB may hamper the fertility of high yielding dairy cows through increased NEFA and decreased glucose concentrations in the FF, directly affecting oocyte quality. Finally, it was also demonstrated in our lab that the embryo quality of lactating high producing dairy cows is inferior compared to that of non-lactating dairy heifers or beef cows.
(21-July-2006)
 

Rotger A, Ferret A, Calsamiglia S, Manteca X (2006) Effects of nonstructural carbohydrates and protein sources on intake, apparent total tract digestibility, and ruminal metabolism in vivo and in vitro with high-concentrate beef cattle diets Journal of Animal Science 84 (5): 1188-1196

KEYWORDS: bovine; high-concentrate diet; nonstructural carbohydrates; protein synchrony; ruminal fermentation; mixed rumen bacteria; dairy-cows; crude protein; microbial fermentation; continuous-culture; finishing steers; barley varieties; different forage; pH fluctuations; milk-yield

SUMMARY: To investigate the effects of synchronizing nonstructural carbohydrate (NSC) and protein degradation on intake and rumen microbial fermentation, four ruminally fistulated Holstein heifers (BW = 132.3 +/- 1.61 kg) fed high-concentrate diets were assigned to a 4 x 4 Latin square design with a 2 x 2 factorial arrangement of treatments studied in vivo and in vitro with a dual-flow continuous culture system. Two NSC sources (barley and corn) and 2 protein sources [soybean meal (SBM) and sunflower meal (SFM)] differing in their rate and extent of ruminal degradation were combined resulting in a synchronized rapid fermentation diet (barley-SFM), a synchronized slow fermentation diet (corn-SBM), and 2 unsynchronized diets with a rapidly and a slowly fermenting component (barley-SBM, and corn-SFM). In vitro, the fermentation profile was studied at a constant pH of 6.2, and at a variable pH with 12 h at pH 6.4 and 12 h at pH 5.8. Synchronization tended to result in greater true OM digestion (P = 0.072), VFA concentration (P = 0.067), and microbial N flow (P = 0.092) in vitro, but had no effects on in vivo fermentation pattern or on apparent total tract digestibility. The NSC source affected the efficiency of microbial protein synthesis in vitro, tending to be greater (P = 0.07) for barley-based diets, and in vivo, the NSC source tended to affect intake. Dry matter and OM intake tended to be greater (P <= 0.06) for corn- than barley-based diets. Ammonia N concentration was lower in vitro (P = 0.006) and tended to be lower in vivo (P = 0.07) for corn- than barley-based diets. In vitro, pH could be reduced from 6.4 to 5.8 for 12 h/d without any effect on ruminal fermentation or microbial protein synthesis. In summary, ruminal synchronization seemed to have positive effects on in vitro fermentation, but in vivo recycling of endogenous N or intake differences could compensate for these effects.
(21-July-2006)
 

Dziba LE, Hall JO, Provenza FD (2006) Feeding behavior of lambs in relation to kinetics of 1,8-cineole dosed intravenously or into the rumen Journal of Chemical Ecology 32 (2): 391-408

KEYWORDS: 1,8-cineole; monoterpenes; feeding; kinetics; elimination; rumen microbes; sheep; possum trichosurus-vulpecula; plant secondary compounds; sagebrush artemisia-tridentata; common brushtail possum; mule deer preference; big sagebrush; essential oils; biochemical diversity; varied diets; ingestion

SUMMARY: The monoterpene 1,8-cineole is a major constituent of the essential oils that adversely influence intake of sagebrush by herbivores, but little is known about the mechanisms of its action. We investigated the influence of 1,8-cineole on the feeding behavior of two groups of sheep, one group dosed intravenously and the other intraruminally. In the first study, we infused 40 mg/kg BW of 1,8-cineole intravenously into four lambs on wk 1, 2, and 4. In the second, we administered 125 mg/kg BW of 1,8-cineole into the rumen of four lambs as a single-bolus dose in wk 1 and 2. Lambs dosed intravenously spent less time feeding than controls (28 vs. 60 min; P < 0.05), as did lambs dosed intraruminally (35 vs. 60 min; P < 0.05). Dosed lambs ate less than controls during rumen dosing studies (P < 0.05). For the intravenous infusion studies, rates of elimination did not differ among weeks (P < 0.05). For the rumen infusion studies, however, the absorption rate constant increased from 0.035/min to 0.076/min from wk 1 to 2, while the absorption half-life declined from 24 to 10 min (P < 0.05). Maximum plasma concentrations and time to reach maximum plasma concentrations were no faster in wk 2 than wk 1, but the primary elimination rate constant was 2.3 times higher in wk 2 (0.058/min) than in wk 1 (0.025/min) (P < 0.05). Dosed lambs exhibited clinical effects-licking of lips, drowsiness, staggering, and 1,8-cineole-smelling breath-that were much more pronounced with intravenous than rumen infusions. Dosing did not affect the acid-base balance. Collectively, these data suggest 1) rapid absorption and distribution of 1,8-cineole was responsible for initiating satiety, while more prolonged excretion was responsible for the duration of the satiety effect, and 2) lambs more readily adapted to 1,8-cineole in the rumen-dose study than in the intravenous-dose study.
(21-July-2006)
 

Yu P (2006) Modeling nutrient supply to dairy cattle from a feedstuff using NRC-2001 (a TDN-based model) with inputs based on in situ and mobile bag technique measurements
Canadian Journal of Animal Science 85 (4): 513-519

KEYWORDS: modeling nutrient supply; dairy cattle; National Research Council; in situ; mobile bag technique; lupins lupinus-albus; nutritive-value; lactating cows; dve/oeb model; horse beans; protein; seeds; digestion; nitrogen; raw

SUMMARY: The objectives of this study were to use the NRC-2001 model with inputs based on in situ and mobile bag techniques to (1) predict the potential nutrient supply to dairy cows using an exampled feed-whole lupin seeds that were systematically toasted and (2) quantitatively determine the effects of toasting (which shifted degradation of protein from the rumen to the abomasum and small intestine without changing intestinal digestion) and optimal toasting conditions by the NRC-2001 model. The quantitative predictions were made in terms of: (1) rumen undegraded and degraded feed protein, (2) truly absorbed undegraded protein, (3) potential microbial protein synthesized in the rumen from rumen available protein or (4) from total digestible nutrients (TDN), (5) truly absorbed rumen synthesized microbial protein, (6) truly absorbed rumen endogenous protein, (7) total metabolizable protein (MP), as well as (8) the protein degradation balance (PDB). The results show that using the NRC-2001 model with inputs based on in situ and mobile bag techniques, the predicted PDB and MP supply to dairy cattle was significantly improved. However, no optimal condition could be obtained from this study due to high PDB values (> 48 g kg(-1) DM) in all the treatments, predicted by the model. With toasting, temperature and/or duration could go still higher than 136 degrees C and/or longer than 15 min to further prevent potential N loss in the rumen if total tract digestion is not depressed. More study is needed. However, the results differed from that published with the DVE/OEB system (a non-TDN-based model) although the two models had significant correlations with high R (> 0.99) values. Using the NRC model, the overall mean for MP was higher (+10 g kg(-1) DM), but the PDB values were lower (-12 g kg(-1) DM) in comparison with that predicted by the non-TDN based model for the whole lupin seeds.
(21-July-2006)
 

Yu PQ (2006) An emerging method for rapid characterization of feed structures and feed component matrix at a cellular level and relation to feed quality and nutritive value Archives of Animal Nutrition 60 (3): 229-244

KEYWORDS: feed inherent structure; feed characterization; biological component matrix; synchrotron FTIR microspectroscopy; feed quality; synchrotron infrared microspectroscopy; ftir microspectroscopy; tissue; barley; rumen

SUMMARY: Feed quality, feed characteristics, nutrient utilization and digestive behaviour are closely related to: (i) total feed composition, (ii) feed intrinsic structures, and (iii) biological component matrix (such as protein to starch matrix, protein to carbohydrate matrix). Conventional "wet'' chemical analysis can determine total chemical composition, but fails to detect the feed intrinsic structures and biological component matrix due to destruction of feed samples during the processing for chemical analysis and the "wet'' chemical analysis cannot link structural information to chemical information within intact feed tissue. Recently, advanced synchrotron-based Fourier transform infrared (FTIR) microspectroscopy has been developed as a non-destructive and non-invasive structural-chemical analytical technique. This technique can link chemical information to structural information of biological samples within intact tissue within cellular dimensions. It can provide four kinds of information simultaneously: tissue composition, tissue structure, tissue chemistry and tissue environment. However, this novel technique has been found mainly for medical science research, extremely rare for feed science and nutrition research. The objective of this review article was to illustrate synchrotron-based FTIR microspectroscopy as a novel research tool for rapid characterization of feed structures at a cellular level and for detection of chemical features and molecular chemical make-up of feed biological component matrix and nutrient interaction. The emphasis of this article was to show that feed structural-chemical features at a cellular level are closely related to feed characteristics, feed quality and nutritive value in animals. The synchrotron-based technology will provide us with a greater understanding of the plant-animal interface.
(21-July-2006)
 

Sawanon S, Kobayashi Y (2006) Synergistic fibrolysis in the rumen by cellulolytic Ruminococcus flavefaciens and non-cellulolytic Selenomonas ruminantium: Evidence in defined cultures Animal Science Journal 77 (2): 208-214

KEYWORDS: fiber digestion; rumen bacteria; Ruminococcus flavefaciens; Selenomonas ruminantium; synergism; wall monosaccharide components; fibrobacter-succinogenes; bacteria; digestion; hemicellulose; degradation; forages

SUMMARY: To investigate the rumen bacterial interaction between cellulolytic Ruminococcus flavefaciens and non-cellulolytic Selenomonas ruminantium, fiber digestibility and fermentation products were determined in defined cultures consisting of these two species. Avicel, orchardgrass hay, rice straw and alfalfa hay were used as substrates for 72 h incubation to monitor digestibility, volatile fatty acids, succinate, lactate and bacterial number. In monoculture, R. flavefaciens digested the fiber sources at 21-32%, while S. ruminantium strains did not. When R. flavefaciens was cocultured with one of three different strains (GA192, S137 and S150) of S. ruminantium, fiber digestion exceeded the value recorded by R. flavetaciens alone. In particular, cocultures with S. ruminantium S137 showed significantly higher digestibility for all the fiber sources than R. flavefaciens alone (P < 0.05). Propionate production and growth of S. ruminantium was notable in all cocultures but not in monocultures. Succinate was accumulated in monoculture of R. flavefaciens, while the accumulation was not observed in cocultures. These results indicate that R. flavefaciens provides fiber hydrolysis products to S. ruminantium as growth substrates. In addition, S. ruminantium could activate R. flavefaciens by rapidly consuming the products. Such cross-feeding between cellulolytic and non-cellulolytic bacteria could enhance fiber digestion, although the extent of the enhancement may depend on strain combinations.
(21-July-2006)
 

Awati A, Williams BA, Bosch MW, Li YC, Verstegen MWA (2006) Use of the in vitro cumulative gas production technique for pigs: An examination of alterations in fermentation products and substrate losses at various time points Journal of Animal Science 84 (5): 1110-1118

KEYWORDS: fermentable carbohydrate; fermentation; in vitro gas production; ruminant feeds; production profiles; large-intestine; rumen fluid; kinetics; fractions; silage

SUMMARY: An experiment was conducted to examine changes in VFA and ammonia concentrations at different time points using 4 fermentable carbohydrate-rich feed ingredients as substrates and feces of unweaned piglets as inoculum. Fecal inoculum was collected, pooled, and mixed from 9 specially raised (no creep feed or antibiotics) crossbred piglets at 3 wk of age. Inulin, lactulose, molasses-free sugar beet pulp, and wheat starch were used as substrates and were fermented in vitro for 72 h (3 replicates per substrate). Cumulative gas production was measured as an indicator of the kinetics of fermentation. In addition, 3 bottles of substrate per time point with similar contents (amounts of substrate, inoculum, and media) were incubated but were allowed to release their gas throughout incubation. For these latter bottles, fermentation fluid was sampled at incubation time points including every hour between 1 and 24 h and at 48 h, and fermentation end products (VFA, lactate, and ammonia) and OM disappearance were measured. Dry matter and ash were analyzed from the postfermentative samples. The pH of the contents from these bottles was also recorded. The correlation in time between fermentation end products and cumulative gas produced was determined. The results showed that the prolongation of fermentation to 72 h, especially in the case of fast-fermenting inulin and lactulose, may lead to a different end product profile (P < 0.001) compared with the profile observed at the time at which most of the substrate has disappeared. Therefore, we concluded that the fermentation product profile at the end of in vitro fermentation at a specific time point cannot be used to compare fermentability of carbohydrate sources with different fermentation kinetics in terms of gas production.
(21-July-2006)
 

Hyslop JJ (2006) In situ and mobile bag methodology to measure the degradation profile of processed feeds in different segments of the equine digestive tract Livestock Science 100 (1): 18-32

KEYWORDS: in situ and mobile bag techniques; feed degradation; digesta passage rate; partitioning digestion; equine; digestibility; passage; ponies; degradability; protein; marker; feces; horse; cecum; rumen

SUMMARY: The purpose of this review paper is to outline developments in the use of the mobile bag and in situ porous bag techniques for use in nutrition studies with equines. Adaptation of these techniques, combined with mathematical modelling of feed degradation profiles and estimates of digesta passage allow the in vivo quantitative partition of feed degradation amongst the major segments of the equine digestive tract. Measurement of dry matter effective degradability values in the small intestine (pre-caecal), caecal and colonic segments of the equine digestive tract for four fibre feeds is described. Digesta passage rates precaecally, in the caecum and in the total tract of equines are also briefly discussed. Examples of how these methods can be used to assess the degradation of forage components in the total tract of equines and the effects of feed processing on feed degradation profiles in the small intestine of equines are also given. In order to ensure that optimum, balanced and healthy equine diets can be formulated in practice, further studies are now required to capitalise on the development of this methodology. Comprehensive experiments should now be undertaken using defined animals and dietary conditions that partition degradation of individual feed constituents in a wide range of common equine feeds across each of the major segments of the equine digestive tract. Partitioning protein digestion between different segments of the equine digestive tract would be particularly beneficial.
(21-July-2006)
 

Akraim F, Nicot MC, Weill P, Enjalbert F (2006) Effects of preconditioning and extrusion of linseed on the ruminal biohydrogenation of fatty acids. 1. In vivo studies Animal Research 55 (2): 83-91

KEYWORDS: biohydrogenation; linseed; preconditioning; extrusion; conjugated linoleic-acid; bovine-milk fat; lactating cows; dairy-cows; heat-treatment; digestibility; trans; oil; isomers; raw
SUMMARY: The extent and intermediates of ruminal biohydrogenation (BH) of fatty acids ( FA) from a blend of linseed and wheat bran ( 70: 30) were investigated in the rumen fluid, rumen particle phase and duodenal flow. The blend was ground through a 3 mm screen and used raw or extruded, or was ground through a 6 mm screen and preconditioned. Three dry Holstein cows fitted with ruminal and duodenal cannulas were used in a 3 x 3 Latin square design, with 18 days adaptation. The diet contained 20% (DM basis) of the linseed based blend. Twelve samples taken over 3 days were composited for analysis of rumen fluid, rumen particle phase and duodenal flow. The BH of FA from linseed resulted in the appearance of a great number of C18:1 intermediates, among which trans-10+11 to trans-16C18:1 were the most abundant. The proportion of cis-9,trans-11C18:2 was low. Preconditioning coarsely ground linseed resulted in a lower extent of C18: 2 and C18:3 BH, and lower proportions of trans-12 to trans-16C18:1 intermediates than extrusion or a lack of processing of finely ground linseed. On the contrary, extrusion did not affect the extent of BH and had no significant effect on the proportions of trans-C18:1 intermediates, but increased the proportion of cis-9, trans-11C18:2 in both rumen phases. Different digesta types resulted in different estimates of BH. The extent of BH and the proportions of trans-C18:1 intermediates were lower in the rumen particle phase and higher in the rumen fluid than in the duodenum. Moreover, interactions between digesta type and treatment of linseed were observed.
(21-July-2006)
 

Brusemeister F, Sudekum KH (2006) Rumen-protected choline for dairy cows: the in situ evaluation of a commercial source and literature evaluation of effects on performance and interactions between methionine and choline metabolism Animal Research 55 (2): 93-104

KEYWORDS: dairy cow; requirement; methionine; choline; methyl group; milk-production; dietary choline; production responses; bovine hepatocytes; increasing amounts; abomasal infusion; net carbohydrate; protein system; fatty-acids; liver

SUMMARY: The interactions were investigated between methionine and choline metabolism due to interchangeable methyl groups. Feeding trials on dairy cows with choline administration were re-evaluated with a focus on methionine balance and the possible effects of supplementary choline on methionine metabolism. In addition, in situ ruminal stability was estimated for a commercial choline supplement. We examined six experiments that included 11 dietary treatments. The Cornell net carbohydrate and protein system was used to estimate nutrient supply and requirements as well as methionine balance; further methionine supply was assessed according to the ideal protein concept. The re-evaluation of feeding trials confirmed the positive effects of supplementary abomasally available choline on milk yield and health of dairy cows. Although these effects were mainly attributed to an elevated export of triglycerides from the liver, beneficial effects may be further caused by an exoneration of methionine metabolism by sparing S-adenosylmethionine. Therefore, the effects on milk yield or other response variables of additional, abomasally available choline could serve as an indicator of methyl group deficiency and thus methionine shortage. Since from theoretical considerations the demand for methyl groups in dairy cows is related to the stage of lactation, requirements for methionine and methyl groups should be taken as separate entities and the latter should be expressed in relation to energy balance or days in milk. Our in situ data indicate that Reashure choline (R) was effectively protected against ruminal degradation because at least 600 g(.)kg(-1) of choline were in a rumen-protected form. In conclusion, (I) supplementary choline may improve the yield of dairy cows by elevating the export of triglycerides from the liver and by sparing methionine as a methyl donor, and (II) the demand for methyl groups still lacks adequate consideration in the design of diets for dairy cows.
(21-July-2006)
 

Salem AZM, Salem MZM, El-Adawy MM, Robinson PH (2006) Nutritive evaluations of some browse tree foliages during the dry season: Secondary compounds, feed intake and in vivo digestibility in sheep and goats Animal Feed Science and Technology 127 (3-4): 251-267

KEYWORDS: foliage; secondary compounds; feed intake; digestibility; sheep goats; mulga acacia-aneura; polyethylene-glycol; antimicrobial activity; daily supplementation; condensed tannins; ceratonia-siliqua; essential oils; gas-production; desert sheep; grass hay

SUMMARY: Four browse tree foliages (Cassia fistula, Schinus molle, Chorisia speciosa and Eucalyptus camaldulensis), native to the semi-arid region of north Egypt, were harvested during the dry season and evaluated for nutritional quality by determination of levels of nutrient and secondary compounds, as well as feed intake and apparent digestibility in sheep and goats. The study consisted of four experiments conducted in sequential 28-day periods that were the same in all respects, except that a different foliage was evaluated in each experiment which used six adult male Rhmani sheep (35 +/- 2.3 kg body weight (BW) at the start of the study) and six crossbred goats (30 +/- 1.56 kg BW). Sheep and goats were randomly divided into two groups of three and offered foliage at a level equal to 1.3 of the previous days voluntary intake of fresh matter and a commercial concentrate, with or without 10 g/animal/d of PEG, at 10 g/kg of BW to meet 0.7 of maintenance metabolizable energy requirements. Foliage crude protein (CP) content ranged from 124 (S. molle) and 128 (C. speciosa) to 185 g/kg DM (C. fistula). Ether extract was highest (97 g/kg) in S. molle. C. fistula had the lowest neutral detergent fiber (NDFom), acid detergent fiber (ADFom) and acid detergent lignin (lignin(sa)), while E. camaldulensis had the highest values. Total phenolics (TP), condensed tannins (CT), saponins (SAP), alkaloids (ALKA), the aqueous fraction (AF) of lectins, polypeptides and starch, and essential oils (EO) were lowest in C. speciosa (29, 21, 3, 0, 4 g/kg DM and 0.40 ml/kg DM, respectively) and highest in E. camaldulensis (102, 68, 15, 5, 3 g/kg DM and 15 ml/kg DM, respectively). Levels of TP, CT, SAP, ALKA and EO were highly positively intercorrelated among foliages, although AF was weakly negatively correlated to all others. Goats consumed 3.9% more foliage dry matter (DM) than sheep per kg BW0.75, and their digestibility was about 8% higher, probably reflecting their better capacity to detoxify secondary compounds in the rumen than sheep. Levels of CT (and due to its correlations, also TP, SAP, ALKA and EO) was a strong predictor of DM intake of PEG unsupplemented foliages within both sheep and goats. PEG increased (P < 0.05) intake of DM and its components in sheep and goats. Digestion of DM and NDFom were not affected by feeding PEG, although digestion of OM, EE and CP were higher (P < 0.05). TP in tree foliages (and due to its correlations, also CT, SAP, ALKA and EO) was not a predictor of the proportional increase in DM with PEG feeding, which was best predicted by level of CP within foliage. Overall, C. speciosa, had the highest nutrient value for both sheep and goats, both without and with PEG feeding, S. molle and C. fistula were intermediate and E. camaldulensis had the lowest nutritive value.
(21-July-2006)
 

Buccioni A, Antongiovanni M, Petacchi F, Mele M, Serra A, Secchiari P, Benvenuti D (2006) Effect of dietary fat quality on C-18 : 1 fatty acids and conjugated linoleic acid production: An in vitro rumen fermentation study Animal Feed Science and Technology 127 (3-4): 268-282

KEYWORDS: artificial rumen; biohydrogenation; fatty acids; conjugated linoleic acid; performance liquid-chromatography; oleic-acid; milk-fat; isomers; biohydrogenation; separation; cows; identification; profiles; inoculum

SUMMARY: Samples of three diets, previously tested with lactating dairy cows, were incubated in vitro with rumen fluid with the aim of monitoring the concentration of cis and trans C-18:1 fatty acids and of the isomers of conjugated linoleic acid with fermentation time.
The three diets had a common forage basis (lucerne hay and maize silage), but different fat sources in the concentrate (basically made up of maize meal and soybean meal). The control diet (diet C) had no fat added and the other two diets were supplemented either with a calcium salt of olive oil (diet O) or with extruded full fat soybean (diet S). The fatty acid pattern in the fermentation vessels was affected by the kind of dietary fat in the samples, both in terms of concentration and of fermentation times (12, 24, 36, 48 h).
Oleic acid (OA), elaidic acid and conjugated linoleic acid (CLA) isomers were particularly looked at. OA was not completely saturated to stearic acid, but isomerized to other acids of the C-18:1 family as well. Vaccenic acid was increased with all the three diets, especially with diet O after 36 h.CLA resulted increased with diet S only (P < 0.05), with significant differences between isomers. The saponification of olive oil appeared to be a partial protection against rumen biohydrogenation. The possibility of affecting the concentration of intermediate acids of the biohydrogenation pathways by dietary means was confirmed.
(21-July-2006)
 

Cone JW, Van Gelder AH, Chai WZ (2006) Fermentation behaviour of the nylon bag washout and degradable fractions determined with the gas production technique Animal Feed Science and Technology 127 (3-4): 319-326

KEYWORDS: degradable fraction; gas production; nylon bag; rumen fermentation; washout fraction; protein degradability; rumen; kinetics

SUMMARY: Most feed evaluation systems for ruminants are based on data obtained with the nylon bag technique. This technique divides the samples in a washout (W) fraction, passing the pores of the nylon gauze of approximately 40 mu m, and a degradable (D) fraction, unable leaving the bags unfermented. Generally, it is assumed that the W-fraction is immediately and completely fermented in the rumen. Experiments were conducted to determine the percentage fast and moderate fermentable components in both the W- and the D-fraction, using the gas production technique. Ten starchy feed ingredients were separated in vitro by filtration over a nylon gauze of 40 mu m. Gas production profiles were recorded of the obtained W- (mean 223 g/kg) and D-fractions (mean 777 g/kg). The results show that on average only 376g/kg of the W-fraction, high in starch, can be regarded as fast fermentable and 624g/kg as moderate fermentable. The moderate fermentable proportion showed a fermentation behaviour comparable with the D-fraction. On the contrary, also 143 g/kg of the D-fraction could be regarded as fast fermentable. The results obtained with the D-fractions obtained by an in vitro method were confirmed with D-fractions obtained according to the nylon bag protocol, using a washing machine with running tap water. It was concluded that the major part of the in situ W-fraction is not immediately fermentable and actually is a washout part of the D-fraction.
(21-July-2006)

Hindrichsen Ida K., Wettstein H.-R., Machmüller A., Bach Knudsen K.E., Madsen J., Kreuzer M. (2006) “Digestive and metabolic utilisation of dairy cows supplemented with concentrates characterised by different carbohydrates”. Animal Feed Science and Technology, (126), 1-2 pp 43-61.

KEYWORDS: carbohydrates, energy, Jerusalem artichoke, soybean hulls, oat hulls, apple pulp.

SUMMARY: A respiration chamber experiment was conducted with 12 Brown Swiss dairy cows fed six concentrates with diverse carbohydrate composition over three experimental periods (n = 6). The complete diets consisted of forage and concentrate (1:1). The concentrates were characterised by individual feedstuffs (oat hulls, soybean hulls, apple pulp, Jerusalem artichoke tubers, molasses, wheat), which were either rich in lignified fibre, non-lignified fibre, pectins, fructans, sugars or starch. On basis of analysed proximate contents and tabulated digestibility values, the complete diets were formulated according to Swiss standards to be isoenergetic (net energy for lactation; NEL) and to meet the requirements of the cows for NEL and absorbable protein at the duodenum. In spite of this attempt, the oat hulls diet, being characterised by a high content of lignified fibre (hemicelluloses and cellulose), was significantly inferior in many respects to the other five experimental diets. This included digestibility and energy metabolisability as well as trends toward lower milk yield and energy retention (milk and body stores). Elevated levels of milk urea and proportions of urine-N relative to N-intake suggested that the oat hulls diet provided the least amount of fermentable energy for rumen microbial protein synthesis. The other five diets did not vary that much in their effect on energy turnover, except in urinary energy loss, which was highest with the Jerusalem artichoke diet. Both diets rich in sugars (molasses and Jerusalem artichoke) were superior in energy utilisation compared to the two diets rich in fibre (oat hulls and soybean hulls); however, this did not result in clear differences in energy retention. Contents of NEL, as measured in conjunction with energy balance, clearly differed from the estimates based on tabulated values and those obtained by regressions based on proximate contents, while regressions based on measured digestibilities gave more reliable results (r = 0.68).
In conclusion, estimation of the true net energy content of concentrates characterised by less frequently used carbohydrates with different properties is unsatisfactory when only approaches relying on analysed proximate contents and tabulated digestibilities are applied.
(10-March-2006)
 

Howe P, Meyer B, Record S, Baghurst K (2006) Dietary intake of long-chain omega-3 polyunsaturated fatty acids: contribution of meat sources Nutrition 22 (1): 47-53

KEYWORDS: omega-3; docosapentaenoic acid; red meat; dietary intakes; alpha-linolenic acid; food sources; cardiovascular-disease; docosapentaenoic acid; risk factor; n-3 PUFA; fish-oil; omega-3-fatty-acids; women; men

SUMMARY Objective: We examined the relative contributions of meat and fish to the dietary intakes of long-chain omega-3 polyunsaturated fatty acids (LCn3PUFAs). Methods: A database detailing 4550 foods and 4298 recipes recorded in the 1995 Australian National Nutrition Survey (NNS95) was updated with new fatty acid compositional data then used to determine intakes from 24-h dietary recalls of 13 858 individuals. This approach was validated with food frequency questionnaires from 8321 of these individuals. Results: Fatty acid intakes were comparable to our previous estimates from NNS95 except for LCn3PUFAs, which were considerably higher. Mean intakes in adults estimated from the 24-h recalls were 75, 71, and 100 mg/d for eicosapentaenoic acid, docosapentaenoic acid (DPA), and docosahexaenoic acid, respectively, giving a total of 246 mg/d. This is 30% greater than our previously published estimate of LCn-3PUFA intake, the difference being attributable to inaccuracies in pre-existing data on the fatty acid composition of certain foods, particularly the DPA content of meats. We estimate that 43% of the LCn-3PUFAs consumed by adults in the NNS95 survey originated from meat, poultry, and game compared with 48% from fish and seafood. Steak and kidney pies and other meat-containing cereal-based products accounted for an additional 4%. Beef and lamb contributed 28% of the total LCn3PUFA intake, whereas pork and poultry contributed 4% and 10%, respectively. Food frequency questionnaires produced similar results. Conclusion: Meat is a major source of LCn-3PUFA, particularly DPA, for most Australians. When DPA is included in the definition of LCn-3PUFAs, almost half the average adult intake of LCn3PUFA appears to originate from meat sources.
(10-March-2006)
 

Pinotti L, Moretti VM, Baldi A, Bellagamba F, Campagnoli A, Savoini G, Cantoni C, Dell'Orto V (2005) Feed authentication as an essential component of food safety and control Outlook On Agriculture 34 (4): 243-248

KEYWORDS: length-polymorphism analysis; species identification; mitochondrial-DNA; bone meal; fishery products; feedstuffs; speciation; protein; RFLP; SSCP; feed; processed animal proteins; safety

SUMMARY: The protracted outbreak of mad-cow disease, repeated episodes of dioxin and mycotoxin contamination, and the issue of labelling genetically modified foods have severely shaken public confidence in the food supply industry, increasing consumer concerns about the origins of the raw materials used in both animal feed and food products. The need to develop improved techniques to characterise feed and food components has consequently become more urgent, and DNA-based technologies promise to be able to meet these needs. DNA methods can establish the origin of species in meat- and fish-based products and feed ingredients, and are the most reliable analytical approaches for authenticating processed foodstuffs. The identification of ingredients in processed feed and food is mandatory not only to ensure correct labelling and assessment of value, but also to avoid health risks related to the presence of toxic contaminants or pathogenic agents.
(10-March-2006)
 

Lee MRF, Tweed JKS, Dewhurst RJ, Scollan ND (2006) Effect of forage : concentrate ratio on ruminal metabolism and duodenal flow of fatty acids in beef steers Animal Science 82: 31-40 Part 1

KEYWORDS: beef cattle; fatty acids; linseed oil; rumen metabolism; conjugated linoleic-acid; trans-octadecenoic acid; dairy-cows; in-vitro; oil supplementation; rumen fermentation; milk-production; sunflower oil; linseed oil; biohydrogenation

SUMMARY: The objective of this study was to determine the proportion of forage in the diet which would maximize duodenal flow of unsaturated fatty acids in beef steers supplemented with linseed oil. A second objective was to determine how diets differing in forage content, but equal in nitrogen (N), energy and lipid supply, would affect the duodenal flow of C-18:1 and conjugated linoleic acid (CLA) isomers. Eight HerefordxFriesian steers (533 +/- 13.6 kg), prepared with rumen and duodenal cannulae were offered one of four forage:concentrate (F:C) ratios: F80C20; F60C40; F40C60 and F20C80 on a dry-matter (DM) basis. All diets were offered at 0.013 body weight and designed to be isonitrogenous and isoenergetic with total lipid made up to 0.06 DM intake with linseed oil. The experimental design was a replicated incomplete 4x4 Latin square with three periods. Increasing the concentrate component in the diet from 0.20 to 0.60 reduced rumen pH from 6.58 to 6.37 and caused a small but significant shift in volatile fatty acid molar proportions, decreasing the non-glucogenic ratio. Rumen ammonia-nitrogen concentration was also significantly reduced with increasing concentrate, from 156.8 to 101.0 mg N per l on F80C20 and F20C80, respectively. Microbial nitrogen (MN) and the efficiency of microbial protein synthesis was significantly elevated as forage level decreased from 51.6 to 72.4 g/day and 17.2 to 27.3 g MN per kg organic matter apparently digested in the rumen, respectively for F80C20 and F20C80. Intake and duodenal flow of C18:1n-9 and C18:2n-6 were significantly higher with increasing concentrate level in the diet whereas C18:3n-3 intake and flow was not different, averaging 143.6 and 6.37 g/day, respectively. There were no differences in the flows of total C18:1 trans or CLA (47.7 and 1.79 g/day, respectively) across the diets. However, although not significantly different in duodenal flow there were trends (P < 0.1) for an increasing proportion of trans-10 and a decreasing proportion of trans-11 when increasing the concentrate in the diet. Biohydrogenation of C18:2n-6 decreased from 0.91 to 0.85 when increasing concentrate in the diet from 0.20 to 0.40 but further increases had no effect. F:C ratio had little effect on the flow of unsaturated fatty acids, C18:1 trans and CLA to the duodenum of beef steers, and this may relate to the ability of the rumen to buffer the large changes in concentrate intake.
(10-March-2006)
 

Greathead HMR, Dawson JM, Craigon J, Sessions VA, Scollan ND, Buttery PJ (2006) Fat and protein metabolism in growing steers fed either grass silage or dried grass British Journal of Nutrition 95 (1): 27-39

KEYWORDS: ruminants; grass silage; dried grass; fat metabolism; protein metabolism; carcass composition; metabolisable energy; chromatography-mass-spectrometry; finishing beef-cattle; forage-based diets; body-composition; leucine metabolism; adipose-tissue; carcass composition; concentrate ratio; lipid-metabolism; growth-hormone

SUMMARY: Cattle fed grass silage diets have been reported to have high carcass fat:protein ratios. The effect of grass silage and dried grass diets, fed at different levels of intake to ensure a range of equivalent metabolisable energy intakes (MEI) from 1.1xmetabolisable energy requirement for maintenance to ad libitum, on fat and protein metabolism in twenty-four HerefordxFriesian steers was investigated. After about 84 d of dietary treatment rates of whole-body fat and protein metabolism were measured, as were rates of lipogenesis in omental, perirenal and subcutaneous adipose tissue. Carcass composition was determined. Animals fed silage had greater (P < 0.001) carcass fat:protein ratios than animals fed dried grass at equivalent levels of MEI. Animals fed silage had lower (P < 0.001) rates of protein gain. Rates of leucine entry and oxidation were lower (P < 0.001) in animals fed silage, but there was no dietary difference in the rate of whole-body protein synthesis. There was no dietary difference in the rate of carcass fat gain, but rates of lipogenesis in perirenal adipose tissue were significantly (P=0.007) higher in animals fed silage. There was no dietary difference in the rate of palmitate and glycerol entry or palmitate oxidation. There were no interactions between MEI and diet, indicating that increments of energy were utilised with the same efficiency from both diets. It was concluded that the high carcass fat:protein ratios of young growing steers was due to limited rates of protein accretion and not to elevated rates of carcass fat accretion.
(10-March-2006)
 

Grant MHJ, Alexander BM, Hess BW, Bottger JD, Hixon DL, Van Kirk EA, Nett TM, Moss GE (2005) Dietary supplementation with safflower seeds differing in fatty acid composition differentially influences serum concentrations of prostaglandin F metabolite in postpartum beef cows Reproduction Nutrition Development 45 (6): 721-727

KEYWORDS: beef cows; lipid supplementation; prostaglandin; linoleic-acid; ewes; progesterone; performance; heifers; tissues; plasma; growth; cattle; period

SUMMARY: Synthesis and secretion of prostaglandin F-2 alpha (PGF(2 alpha)) is elevated following parturition and exerts divergent effects on the re-establishment of fertile estrous cycles in cows. The objective of these experiments was to determine if oil seed supplements differing in fatty acid composition differentially influence serum concentrations of the specific PGF(2 alpha) metabolite, PGFM. Safflower seed supplements were formulated to provide 5% of dry-matter intake as fat. In Trial 1, 24 multiparous beef cows were individually fed control (beet pulp-soybean meal) or cracked high-linoleate safflower seed (78% 18:2n-6) supplements for 80 d postpartum. Linoleate supplemented cows had greater (P < 0.001) serum concentrations of PGFM than control cows. In Trial 2, primiparous beef cows (n = 36) were individually fed control (cracked corn-soybean meal), cracked high-linoleate (76% 18:2n-6) or -oleate (72% 18: 1 n-9) safflower seed supplements for 92 d postpartum. As in Trial 1, serum concentrations of PGFM were greater (P <= 0.04) in linoleate than control or oleate supplemented cows. Serum concentrations of PGFM, however, did not differ (P = 0.40) among oleate and control supplemented cows. Although potential impacts on reproductive performance remain to be proven, dietary oil supplements high in linoleate, but not oleate, increased serum concentrations of PGFM compared to control supplements.
(10-March-2006)
 

Petric N, Levart A, Cepon M, Zgur S (2005) Effect of production system on fatty acid composition of meat from Simmental bulls Italian Journal of Animal Science 4: 125-127 Suppl. 3

KEYWORDS: pasture; cattle; fatty acids; muscle; muscle; lamb; beef

SUMMARY: The objective of the study was to asses the effect of the production system on fatty acids (FA) composition of intramuscular fat of three muscles (longissimus dorsi, semitendinosus, diaphragmae) from Simmental bulls. Bulls (n=8) were fattened either with maize silage and concentrates or on pasture. Grazing bulls showed a significant lower percentage of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA), but had higher percentage of polyunsaturated fatty acids (PUFA) and conjugated linoleic acid. The n-6/n-3 PUFA ratio was significantly lower (P < 0.001) and the PUFA/SFA ratio was significantly higher (P < 0.001) in muscles of grazing bulls. The lowest SFA percentage was found in semitendinosus (36.5 +/- 0.8) followed by longissimus dorsi (44.4 +/- 0.8) and diaphragmae (48.2 +/- 0.8) muscle. The percentage of PUFA and n-3 PUFA was the highest in semitendinosus muscle, while the n-6/n-3 PUFA ratio was similar in all three analysed muscles.
(10-March-2006)
 

Kumm KI (2005) Economically sustainable preservation of grazing-dependent biodiversity in Sweden with Canadian ranching systems Outlook on Agriculture 34 (4): 255-260

KEYWORDS: beef cattle; biodiversity; decoupling; environmental allowances; seminatural pastures; British Columbia

SUMMARY: There is apprehension that the decoupling of EU income support will result in shortages of livestock for preservation of biodiversity in Swedish seminatural pastures. However, in a region studied in British Columbia with natural conditions similar to those in central Sweden but with no income support, one-third of the agricultural land is semi-natural pastures and the number of beef cattle has increased. This can be explained by the availability of cheap outdoor wintering of cattle and low opportunity cost of land. The results suggest that the abolition of income support and the tradition of expensive indoor wintering, but maintained environmental allowance for grazing, would result in land use in large parts of Sweden similar to that in the British Columbia region.
(10-March-2006)
 

Cerdeno A, Vieira C, Serrano E, Lavin P, Mantecon AR (2006) Effects of feeding strategy during a short finishing period on performance, carcass and meat quality in previously-grazed young bulls Meat Science 72 (4): 719-726

KEYWORDS: bulls; finishing; performance traits; carcass quality; beef quality; subcutaneous fat thickness; high-energy diet; beef quality; palatability characteristics; muscle characteristics; feedlot performance; steers; grain; forage; cattle

SUMMARY: Twenty-one Brown Swiss x Limousin young bulls reared on pasture were housed for a short finishing period (60 days). CA group (concentrate-ad libitum group) received concentrate and straw ad libitum for the whole finishing period. CR group (concentrate-restricted group) received 4 kg of concentrate/animal per day and ad libitum alfalfa hay throughout the 60 days. CRA group (concentrate-restricted/ad libitum group) received the same diet as CR group for the first 30 days and the same diet as CA group for the last 30 days. CA and CRA groups presented higher fatness values. Myoglobin concentration in muscle was highest in CA group (P < 0.05) and carotene content in subcutaneous fat was highest in CR group (P < 0.01), while Warner-Bratzler shear force and sensory traits were unaffected (P > 0.05). It is concluded that, in this type of young animal, 4 kg concentrate plus ad libitum alfalfa hay for a 60-day finishing period, despite lower fatness, provides carcasses and meat with acceptable quality characteristics, similar to those obtained from ad libitum fed animals for the same period.
(10-March-2006)
 

Ponter AA, Parsy AE, Saade M, Mialot JP, Ficheux C, Duvaux-Ponter C, Grimard B (2006) Effect of a supplement rich in linolenic acid added to the diet of post partum dairy cows on ovarian follicle growth, and milk and plasma fatty acid compositions Reproduction Nutrition Development 46 (1): 19-29

KEYWORDS: linolenic acid; milk and plasma fatty acids; follicle growth; dairy cows; postpartum reproductive function; late-gestation; beef-cows; cattle; prostaglandins; performance; metabolism; fertility; digestion; insulin

SUMMARY: The objective of this study was to determine the effect of a linseed supplement on follicle growth, progesterone concentrations and milk and plasma fatty acids in dairy cows post partum. Sixteen Holstein cows were given a basal total mixed diet plus one of two supplements: control ( C; extruded soybeans; n = 8) or linseed ( L; extruded linseeds; n = 8). One month after calving oestrous cycles were synchronised ( PRID(R)). Follicle growth and milk progesterone concentrations were measured every 2 d over the induced oestrous cycle. Milk production characteristics were unaffected by treatment. The L cows lost significantly more BCS than the C cows ( P < 0.01). Plasma insulin, glucose and urea were unaffected by the treatment. Plasma NEFA tended to be affected by the treatment ( L > C, P = 0.08). The proportions of 18: 3n- 3 in milk and plasma were increased by L compared to C ( P < 0.001 and P < 0.01, respectively). There was an effect of dietary supplement on the numbers of small follicles ( L < C, P < 0.05). Milk progesterone was unaffected by treatment. In conclusion, the increased supply of 18: 3n- 3 to the cows had only a modest effect on follicle populations and corpus luteum activity was unchanged.
(10-March-2006)
 

de Andrade PVD, Schmidely P (2006) Effect of duodenal infusion of trans10,cis12-CLA on milk performance and milk fatty acid profile in dairy goats fed high or low concentrate diet in combination with rolled canola seed Reproduction Nutrition Development 46 (1): 31-48

KEYWORDS: milk fatty acids; t10,c12-C18 : 2 infusion; canola seed; goat; conjugated linoleic-acid; abomasal infusion; lipid-synthesis; cows; CLA; trans-10; yield; inhibition; isomers; beef

SUMMARY: The effect of t10, c12- C18: 2 on milk production, and fatty acid (FA) profile of milk fat was studied in 8 goats infused duodenally with t10, c12- C18: 2 (2 g. 10 h-1) during 3 days, followed by a 2- day infusion of skim milk (SM). The goats were assigned to 4 diets in a factorial arrangement constituted by low (L = 45%) or high (H = 65% of the diet DM) percentage of concentrate without (CS0) or with (CS20) rolled canola seed (20% of the concentrate DM). Milk samples were collected before (basal), and during the t10, c12- C18: 2 and SM infusions. The t10, c12- C18: 2 in milk fat increased from undetectable basal values to an average of 0.39% of total FA in the 3rd day of t10, c12-C18: 2 infusion. DMI, milk yield, and the contents and yield of milk fat, protein, and lactose were similar between basal and the t10, c12- C18: 2 infusion. The concentration of saturated FA with 4 to 16C did not change during the t10, c12- C18: 2 infusion, whereas C18: 0 increased, particularly in the milk fat of the CS20 group. The t10, c12- C18: 2 infusion increased the t10- and t11- C18: 1 (except a reduction in t11- C18: 1 for the H- CS20 group), and it decreased the c9, t11- C18: 2 in milk fat, particularly for the H- CS20 group. The t10, c12- C18: 2 infusion reduced the c9, t11- C18: 2/ t11- C18: 1 ratio, particularly for the CS0 group. The results indicate that mammary lipogenesis in dairy goats was not decreased by t10, c12- C18: 2, however, the desaturation of long chain FA appeared to be equally affected as in dairy cows. This reduction in the desaturase index of milk fat could have been a direct effect of t10, c12- C18: 2, or mediated via an increase in t10- C18: 1.
(10-March-2006)
 

Kumm KI (2005) Economically sustainable preservation of grazing-dependent biodiversity in Sweden with Canadian ranching systems Outlook on Agriculture 34 (4): 255-260

KEYWORDS: beef cattle; biodiversity; decoupling; environmental allowances; seminatural pastures; British Columbia

SUMMARY: There is apprehension that the decoupling of EU income support will result in shortages of livestock for preservation of biodiversity in Swedish seminatural pastures. However, in a region studied in British Columbia with natural conditions similar to those in central Sweden but with no income support, one-third of the agricultural land is semi-natural pastures and the number of beef cattle has increased. This can be explained by the availability of cheap outdoor wintering of cattle and low opportunity cost of land. The results suggest that the abolition of income support and the tradition of expensive indoor wintering, but maintained environmental allowance for grazing, would result in land use in large parts of Sweden similar to that in the British Columbia region.
(10-March-2006)
 

Cerdeno A, Vieira C, Serrano E, Lavin P, Mantecon AR (2006) Effects of feeding strategy during a short finishing period on performance, carcass and meat quality in previously-grazed young bulls Meat Science 72 (4): 719-726

KEYWORDS: bulls; finishing; performance traits; carcass quality; beef quality; subcutaneous fat thickness; high-energy diet; beef quality; palatability characteristics; muscle characteristics; feedlot performance; steers; grain; forage; cattle

SUMMARY: Twenty-one Brown Swiss x Limousin young bulls reared on pasture were housed for a short finishing period (60 days). CA group (concentrate-ad libitum group) received concentrate and straw ad libitum for the whole finishing period. CR group (concentrate-restricted group) received 4 kg of concentrate/animal per day and ad libitum alfalfa hay throughout the 60 days. CRA group (concentrate-restricted/ad libitum group) received the same diet as CR group for the first 30 days and the same diet as CA group for the last 30 days. CA and CRA groups presented higher fatness values. Myoglobin concentration in muscle was highest in CA group (P < 0.05) and carotene content in subcutaneous fat was highest in CR group (P < 0.01), while Warner-Bratzler shear force and sensory traits were unaffected (P > 0.05). It is concluded that, in this type of young animal, 4 kg concentrate plus ad libitum alfalfa hay for a 60-day finishing period, despite lower fatness, provides carcasses and meat with acceptable quality characteristics, similar to those obtained from ad libitum fed animals for the same period.
(10-March-2006)
 

Wells JE, Berry ED, Varel VH (2005) Effects of common forage phenolic acids on Escherichia coli O157 : H7 viability in bovine feces. Applied and Environmental Microbiology 71 (12): 7974-7979

KEYWORDS: enterica serovar typhimurium; salmonella-enterica; manure compost; beef-cattle; survival; prevalence; slaughter; rumen; inactivation; persistence

SUMMARY: Ruminant animals are carriers of Escherichia coli 0157:117, and the transmission of E. coli 0157:117 from cattle to the environment and to humans is a concern. It is unclear if diet can influence the survivability of E. coli 0157:117 in the gastrointestinal system or in feces in the environment. Feces from cattle fed bromegrass hay or corn silage diets were inoculated with E. coli 0157:117, and the survival of this pathogen was analyzed. When animals consumed bromegrass hay for < 1 month, viable E. coli 0157:117 was not recovered after 28 days postinoculation, but when animals consumed the diet for > 1 month, E. coli 0157:117 cells were recovered for > 120 days. Viable E. coli 0157:117 cells in feces from animals fed corn silage were detected until day 45 and differed little with the time on the diet. To determine if forage phenolic acids affected the viability of E. coli 0157:117, feces from animals fed corn silage or cracked corn were amended with common forage phenolic acids. When 0.5% trans-cinnamic acid or 0.5% para-coumaric acid was added to feces from silage-fed animals, the E. coli 0157:117 death rate was increased significantly (17-fold and 23-fold, respectively) compared to that with no addition. In feces from animals fed cracked corn, E. coli 0157:117 death rates were increased significantly with the addition of 0.1% and 0.5% trans-cinnamic acid (7- and 13-fold), 0.1% and 0.5% p-coumaric acid (3- and 8-fold), and 0.5% ferulic acid (3-fold). These data suggest that phenolic acids common to forage plants can decrease viable counts of E. coli 0157:H7 shed in feces.
(10-March-2006)
 

Therkildsen M (2005) Muscle protein degradation in bull calves with compensatory growth. Livestock Production Science 98 (3): 205-218

KEYWORDS: muscle protein turnover; calpain; fractional breakdown rate; insulin-like growth factor 1; skeletal-muscle; beef-cattle; igf-i; friesian calves; calpain system; meat quality; mu-calpain; turnover; pigs; tenderness

SUMMARY: Twelve 5-month-old bull calves were allocated to two feeding strategies: AA, 6 calves were fed ad libitum 34 weeks; and RA, 6 calves were fed restrictively for 14 weeks with an intake of 50% of the metabolic energy and protein eaten by the AA calves, followed by ad libitum feeding for 20 weeks. At the end of the 14-week restriction period, and after 2, 5, 8, 11, 14 and 17 weeks of re-alimentation, urine, blood and muscle biopsy samples from M longissimus dorsi (LD) were collected. The urine was analysed for 3-methylhistidine for determination of the fractional breakdown rate of muscle protein (FBR). The FBR was depressed during restricted feeding (1.4 versus 2.0%/day; P=0.05), however, during re-alimentation where the calves exerted compensatory growth, the FBR increased and reached a maximum after 5 weeks into this period (3.1 versus 1.9%/day; P < 0.001). The maximal FBR in the RA calves coincided with a maximum concentration of RNA and DNA in LD, and a maximal fractional rate of growth. The activity of p-calpain in LD and the concentration of IGF-I in serum were decreased at the end of the restriction period but increased as soon as energy was offered ad libitum. The results support the hypothesis that muscle protein turnover is affected by a restriction/re-alimentation feeding strategy, and that muscle protein degradation reaches a maximum during the re-alimentation period, which exceeds that of control animals.
(10-March-2006)
 

Valvo MA, Lanza M, Bella M, Fasone V, Scerra M, Biondi L, Priolo A (2005) Effect of ewe feeding system (grass v. concentrate) on intramuscular fatty acids of lambs raised exclusively on maternal milk. Animal Science 81: 431-436 Part 3

KEYWORDS: concentrates; ewe milk; fatty acids; lamb (meat); pastures; conjugated linoleic-acid; meat quality; longissimus-thoracis; beef; cows; cla; nutrition; carcass; tissues; diet

SUMMARY: Twenty pregnant Comisana ewes were divided into two groups of 10. One group was allowed to graze a vetch pasture (grass). The second group of animals was housed collectively in a pen and was given hay and concentrates (concentrate). After lambing, all the ewes were allowed to stay with the respective lambs between 18: 00 h and 07: 00 h of the following day in two different pens. Therefore all the lambs were raised exclusively on maternal milk. The lambs were slaughtered at 38 days of age. Milk and lamb meat (longissimus dorsi muscle) fatty acids were analysed. Ewes on grass produced milk with a lower (P < 0.001) proportion of saturated fatty acids and with a higher proportion of both monounsaturated (P < 0.05) and polyunsaturated fatty acids (P < 0.01) than ewes given concentrates. Trans-vaccenic acid was significantly higher (P < 0.001) in milk from grass-fed animals compared with ewes given concentrates. Linoleic acid (C18 : 2 n-6) tended to be higher (P = 0.06) in milk from ewes on concentrates while linolenic acid (C18 : 3 n-3) was significantly higher (P < 0.001) in milk from animals grazing pasture. Conjugated linoleic acid (cis-9, trans-11 C18 : 2) was almost double in milk from grass-fed ewes compared with animals given concentrates (P < 0.001). Regarding lamb tissue, trans-vaccenic acid (C18 : 1 trans-11) was higher (P = 0.01) in the fat from lambs raised by grazing ewes. Linoleic acid (C18 : 2 n-6) was at higher concentration (P < 0.001) in the fat from lambs raised by ewes given concentrates. Linolenic acid (C18 : 3 n-3) was increased three-fold (P < 0.001) in the fat of lambs from the grass group compared with lambs suckled by ewes given concentrates. The isomer cis-9, trans-11 of conjugated linoleic acid was present at double concentration (P < 0.001) in the fat from animals raised by grazing ewes. Eicosapentaenoic (C20 : 5 n-3; EPA) and docosaesaenoic (C22 : 6 n-3; DHA) acids were higher (respectively P < 0.001 and P = 0.01) in the intramuscular fat from lambs from the grass group compared with animals from the concentrate group. The n-6/n-3 ratio was lower (P < 0.001) in the meat from lambs raised by grazing ewes. Overall this trial showed that the ewe feeding system strongly affects intramuscular fatty acids even in lambs raised exclusively on maternal milk.
(10-March-2006)
 

Marino R, Albenzio M, Girolami A, Muscio A, Sevi A, Braghieri A (2006) Effect of forage to concentrate ratio on growth performance, and on carcass and meat quality of Podolian young bulls. Meat Science 72 (3): 415-424

KEYWORDS: forage to concentrate ratio; Podolian cattle; meat fatty acid composition; organic farming; meat quality; grass-silage; fatty-acids; lipid oxidation; bovine muscles; beef; grain; tenderness; nutrition; pastures; system

SUMMARY: The effect of forage to concentrate ratio: 60-40 [high concentrate group (HQ and 70-30 [low concentrate group (LC)] on growth, slaughtering performance and meat quality were evaluated in twenty organically farmed Podolian young bulls. Meat quality characteristics were measured on three different muscles [Longissimus dorsi (LD), Sentimembranosus (SM) Semitendinosus (ST)], vacuum-packaged and chilled stored at 2-4 degrees C for 15 days. The animals in the HC group had higher weight gain than those in the LC group (P < 0.05). Slaughter data were not influenced by ration composition. The higher forage to concentrate ratio produced an improvement in fatty acid composition of the three muscles, with a higher polyunsaturated to saturated ratio (P < 0.001). Vitamin E and malondialdehyde (MDA) contents were not affected by the feeding treatment. Panel scores for tenderness and flavour (P < 0.01) and Warner-Bratzler Shear force (P < 0.001) were significantly affected by muscle, the LD muscle being the most tender and the richest in flavour but they not affected by dietary treatment.
(10-March-2006)
   

Alfaia CMM, Ribeiro VSS, Lourenco MRA, Quaresma MAG, Martins SIV, Portugal A, Fontes CMGA, Bessa RJB, Castro MLF, Prates JAM (2006) Fatty acid composition, conjugated linoleic acid isomers and cholesterol in beef from crossbred bullocks intensively produced and from Alentejana purebred bullocks reared according to Carnalentejana-PDO specifications. Meat Science 72 (3): 425-436

KEYWORDS: beef; fatty acids; CLA isomers; cholesterol; meat quality; production systems: performance liquid-chromatography; stearoyl-coa desaturase; intramuscular fat; meat quality; cla isomers; dairy-cows; nutritional factors; gas-chromatography; milk lipids; muscle

SUMMARY: The purpose of this study was to characterise and compare the nutritional value of Portuguese Carnalentejana-PDO beef, obtained from Alemejana purebred bullocks reared in a semi-extensive system, with the meat from Alemejana x Charolais crossbred bullocks produced in a conventional intensive concentrate-based system. In addition, seasonal changes in Carnalentejana-PDO beef quality were assessed, by analysing meat samples from animals slaughtered in early autumn and late spring. The results showed that beef-PDO has different intramuscular fat characteristics in comparison with meat from crossbred bullocks fed intensively with concentrate. However, the finishing period of Alentejana purebred bullocks with concentrate seems to attenuate most of the typical grass-fed characteristics of meat fat, Nevertheless, from a human nutrition perspective, Carnalentejana-PDO beef seems to be healthier than that from intensively reared animals since it has a lower n - 6/n - 3 ratio, although always above the recommended guidelines for human diet, and higher proportions of c9,t11 conjugated linoleic acid (CLA) isomer and total CLA relative to saturated fatty acids plus total cholesterol (CLA/SFA + CHR). Furthermore, no seasonal variation in the nutritional quality of beef-PDO was apparent. Taken together, the data indicate that Carnalentejana-PDO beef is of greater nutritional value than intensively produced beer from crossbred bullocks throughout the year.
(10-March-2006)
 

Sarries MV, Murray BE, Troy D, Beriain MJ (2006) Intramuscular and subcutaneous lipid fatty acid profile composition in male and female foals. Meat Science 72 (3): 475-485

KEYWORDS: Longissimus dorsi; fatty acid; adipose tissue; lipids; foals; adipose-tissue; carcass characteristics; chemical-composition; anatomical location; wagyu cattle; breed type; steers; growth; beef; muscle

SUMMARY: This study characterised the lipid classes of Longissimus dorsi (LD) muscle and the fatty acid profiles of the LD intramuscular fat and subcutaneous (SC) adipose tissue of male and female foal mixed populations. Two animal groups were studied based on slaughter ages of 16 and 24 months. The sex of the animals had no statistical significance in the lipid fractions of the LD muscle or in the intramuscular fatty acids (p >= 0.05). In contrast, there was a significant effect of sex on the fatty acid profile of the SC adipose tissue. Furthermore, the livestock production system showed difference in both lipid class and fatty acid profiles from the LD and SC adipose tissues. The LD of 24-month old foals had lower phospholipids content (p <= 0.001), displayed little difference in saturated fatty acids (SFA) (p <= 0.1), exhibited higher levels of monounsaturated fatty acids (MUFA) (p <= 0.05) and lower levels of polyunsaturated fatty acids (PUFA) (P <= 0.05) compared with that of the 16-month old foals. Furthermore, the fatty acid profile of the SC adipose tissue of the 24-month old foals had higher SFA (p <= 0.05) and PUFA (p <= 0.01) with lower amounts of MUFA (p <= 0.001) relative to the 16-month old foals.
(10-March-2006)
 

Clapham WM, Foster JG, Neel JPS, Fedders JM (2005) Fatty acid composition of traditional and novel forages. Journal of Agricultural and Food Chemistry 53 (26): 10068-10073

KEYWORDS: fatty acids; forage; ruminant nutrition; forage-finished beef; conjugated linoleic acid; conjugated linoleic-acid; fish-oil; milk; diets; cattle; grass

SUMMARY: Managing the fatty acid composition of grazing ruminant diets could lead to meat and milk products that have higher conjugated linoleic acid (CLA) concentrations, but forage fatty acid dynamics must be more fully understood for a range of forages before grazing systems can be specified. The fatty acid profiles of 13 different forages, including grasses, legumes, and forbs, grown under greenhouse conditions, were determined. Three separate harvests, at 3-week intervals, were made of each plant material. a-Linolenic [C18:3, 7.0-38.4 mg g(-1) of dry matter (DM)], linoleic (C18:2, 2.0-10.3 mg g(-1) of DM), and palmitic (C16:0, 2.6-7.5 mg g(-1) of DM) acids were the most abundant fatty acids in all species at each harvest, together representing similar to 93% of the fatty acids present. Concentrations of fatty acids declined as plants developed, but the fractional contribution of each fatty acid to total fatty acids remained relatively stable over time. Grasses had a uniform composition across species with a mean of 66% of total fatty acids provided by C18:3, 13% by C18:2, and 14% by C16:0. The fractional contribution of C18:3 to total fatty acids was lower and more variable in forbs than in grasses. Intake of fatty acid by grazing ruminants would be affected by the forage species consumed.
(10-March-2006)
 

Dannenberger D, Lorenz S, Nuernberg G, Scollan N, Ender K, Nuernberg K (2006) Analysis of fatty aldehyde composition, including 12-methyltridecanal, in plasmalogens from Longissimus muscle of concentrate- and pasture-fed bulls. Journal of Agricultural and Food Chemistry 54 (1): 182-188

KEYWORDS: fatty aldehydes; plasmalogens; phospholipids; 12-methyltridecanal; beef; pasture; HPLC; dinitrophenylhydrazones; acid-composition; stewed beef; ethanolamine; phospholipids; biosynthesis; system; cattle; meat; diet; odorants

SUMMARY: In a large study, 64 German Holstein and German Simmental bulls were randomly allocated to either an indoor concentrate system or periods of pasture feeding followed by a finishing period on a concentrate containing linseed to enhance the contents of beneficial fatty acids in beef. This paper reports the diet effects on the concentration of 12-methyltridecanal (12-MT) and further fatty aldehydes released from plasmalogens in the phospholipids of longissimus muscle of the bulls. Because of the trace level of the important odorant 12-MT in beef, the determination of fatty aldehydes in phospholipids was done by acidic hydrolysis and the reaction of the aldehydes with 2,4-DNPH followed by high-pressure liquid chromatography (HPLC) analysis. The diet affected the 12-MT concentrations in the muscle phospholipids of both breeds. Pasture feeding significantly increased the 12-MT concentrations up to g/100 g fresh muscle in the muscle phospholipids of German Holstein andm350  German Simmental bulls as compared with the concentrate-fed bulls. Furthermore, pasture feeding resulted in a significant increase of n-octadecanal in the muscle phospholipids of both breeds up to 39.5 mg/100 g fresh muscle. The concentration of n-hexadecanal was not affected by the diet. Pasture feeding as compared to concentrate feeding significantly decreased the concentration of n-octadec-9-enal in the muscle phospholipids. Summarizing, pasture feeding increased the 12-MT concentration, which can be associated with meat of more intensive aroma and better taste.
(10-March-2006)
 

Rotger A, Ferret A, Calsamiglia S, Manteca X (2006) In situ degradability of seven plant protein supplements in heifers fed high concentrate diets with different forage to concentrate ratio Animal Feed Science and Technology 125 (1-2): 73-87

KEYWORDS: heifers; high concentrate diets; in situ nitrogen degradability; plant protein supplements; dry-matter; intestinal degradability; microbial fermentation; nitrogenous compounds; insitu evaluation; pH fluctuations; basal diet; digestion; rumen; degradation

SUMMARY: Four Holstein heifers (297.5 +/- 27.7 kg BW) fed high concentrate diets were used in a crossover experiment in order to characterize the rumen fermentation pattern, and to estimate by the in situ method rumen degradation kinetics of alfalfa hay and seven plant protein supplements: solvent-extracted soybean meal, solvent-extracted sunflower meal, peas (Pisum sativum L.), lupin seeds (Lupinus sp.), broadbean (Vicia faba L.), horsebean (Vicia faba L. var equina) and vetch (Vicia sativa L.), in high concentrate diets with different forage to concentrate ratio. Heifers were fitted with a ruminal cannula. The experiment was performed in two 30-day periods, 15 days of diet adaptation and 15 days of sampling. At each period, heifers were offered one of two total mixed rations (12:88 versus 30:70 forage to concentrate ratio), two heifers per diet, on ad libitum basis. After the first period, heifers switched treatments. Intake of dry matter (DM), organic matter, crude protein and neutral detergent fibre (NDF), expressed as kg/day, did not differ between treatments, but DM intake, expressed as g/kg metabolic body weight (BW), was higher in the 12:88 diet. Average rumen pH was 6.0 in both diets, and the time pH was below 5.8, which is considered as a critical threshold for fibre degradation, was the same for both treatments (10.4 +/- 1.6 h). Average ammonia nitrogen and volatile fatty acid (VFA) concentrations did not differ between treatments and individual VFA proportions were typical of high concentrate diets. Average effective degradability of DM (0.62 +/- 0.02) and NDF (0.25 +/- 0.03) of alfalfa hay were low and no differences were detected between treatments. The same extent of NDF degradation, together with the same proportions of VFA would indicate that both diets had the same fibrolytic activity. Forage to concentrate ratio did not affect rumen nitrogen degradability of any protein supplements incubated in situ. Corrected effective degradability for small particle losses of sunflower meal (0.78) was higher than legume seeds, which were not statistically different between each other and ranged from 0.63 to 0.66. Soybean meal had the lowest degradability value (0.61). These nitrogen degradation values must be considered more valid for beef cattle formulation of high concentrate diets than data obtained with forage diets.
(10-March-2006)
 

Villarreal M, Cochran RC, Rojas-Bourrillon A, Murillo O, Munoz H, Poore M (2006) Effect of supplementation with pelleted citrus pulp on digestibility and intake in beef cattle fed a tropical grass-based diet (Cynodon nlemfuensis) Animal Feed Science and Technology 125 (1-2): 163-173

KEYWORDS: citrus pulp; in vivo digestibility; intake; beef cattle supplementation; ADAI and IADF internal markers; Cynodon nlemfuensis; in-vitro digestibility; monosaccharide constituents; net carbohydrate; nutritive-value; protein system; dairy-cattle; rations; cows; fermentation; performance

SUMMARY: Citrus pulp is an important by-product for sub-tropical and tropical ruminant animal production. In this study, three steers (average body weight = 324 +/- 16 kg) were randomly assigned to three levels of pelleted citrus pulp (PCP) supplementation (0, 1.25, and 2.5 kg animal(-1) d(-1); as-fed) in a 3 x 3 Latin square design to evaluate its effects on forage intake, digestion, and ruminal pH. The basal diet was stargrass (Cynodon nlemfuensis) harvested and chopped every day and fed fresh. Supplementation with increasing amounts of PCP tended (P <= 0.10) to result in a linear increase in digestibility of total diet dry matter (DM) and organic matter (OM), but no effects were noticed for digestibility of forage DM or total diet neutral detergent fiber. Forage DM intake decreased linearly (P=0.03) with increasing PCP supplementation, although the decrease tended (quadratic; P=0.08) to be of greater magnitude at the highest level of supplementation. Both a linear increase (P < 0.01) and a quadratic trend (greatest increase with first level of supplementation; P=0.09) were also observed for intake of total digestible OM. Average ruminal pH was between 6.6 and 7.2 and was not affected (P=0.29) by supplementation treatment. Although supplementation with PCP depressed forage consumption somewhat, little effect on forage digestion was observed. The provision of digestible OM in the form of supplement was greater than that lost via depressed forage consumption, resulting in an overall increase in energy supply. Our results suggest that high levels of citrus pulp to beef cattle can lower forage intake, but increase total energy intake. High levels of citrus pulp supplementation could be beneficial in combination with forages high in rumen dagradable protein. Systems using grasses with higher ruminally degradable protein content than we used, may benefit from this extra supply of energy which should be tested in a further experiment.
(10-March-2006)
 

Nolte JV, Ferreira AV (2005) The effect of rumen degradable protein level and source on the duodenal essential amino acid profile of sheep South African Journal of Animal Science 35 (3): 162-171

KEYWORDS: amino acid; microbial protein; rumen degradable protein; urea; casein; microbial-growth rates; ruminal fermentation; feed-intake; chemical-composition; nitrogen-metabolism; range forage; beef steers; in-vitro; supplementation; urea

SUMMARY: Two trials were conducted to determine the effects of rumen degradable protein (RDP) level and source on the duodenal essential amino acid (AA) composition of Dohne Merino wethers. The animals had ad libitum access to wheat straw (32 g crude protein (CP)/kg DM; 742 g neutral detergent fibre (NDF)/kg DM) and water. In the first experimental treatments casein provided 0, 40, 80, 120 and 160 g supplemental RDP/d. In experiment two, urea-nitrogen replaced 0, 25, 50, 75 and 100% of the true protein in the isonitrogenous treatments. Expressing essential AA concentration as a percentage of duodenal protein indicated that increasing RDP levels tended to decrease arginine, but significantly increased tryptophan concentrations. Histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, valine and total essential AA concentrations were not affected by dietary RDP level. Increasing the urea-N content of RDP supplements significantly decreased isoleucine, leucine, lysine, phenylalanine, tryptophan, valine and total essential amino acid (TEAA) concentrations. Histidine and threonine proportions also tended to decrease with higher non-protein N levels. When the essential AA profile is expressed in relation to lysine, the concentrations of histidine, leucine, phenylalanine and threonine decreased significantly. Arginine and valine showed a decreasing trend and tryptophan increased significantly as RDP levels were raised. The largest differences appeared between 0 and 40 g RDP supplementation, while the AA patterns for the rest of the treatments remained relatively constant. Substituting urea for true RDP induced a variable response in arginine and isoleucine, but did not affect any of the other AA's. Increasing RDP intakes significantly increased the duodenal flow of every essential AA, except arginine, and showed a strong tendency to increase TEAA flow as well. Replacing true RDP with urea significantly reduced the flow of methionine and tryptophan and also tended to decrease lysine availability in the duodenum. Individual AA and TEAA flow to the duodenum were also numerically decreased by a minimum of 34% as urea-N was increased. It appears that the qualitative duodenal essential AA profile in sheep fed low quality forages is relatively insensitive to RDP level or source. The daily essential AA flow to the duodenum seems to be compromised by urea substitution for true RDP.
(10-March-2006)
 

Van Saun RJ (2006) Nutrient requirements of South American camelids: A factorial approach Small Ruminant Research 61 (2-3): 165-186

KEYWORDS: llama; alpaca nutrient requirements; digestion; nutrition; alpacas lama-pacos; guanacoe f-glama; vitamin-d status; voluntary intake; biochemical values; glucose-tolerance; hepatic lipidosis; reference ranges; urea nitrogen; united-states

SUMMARY: Literature describing digestive physiology and defining specific nutrient requirements for llamas and alpacas was reviewed. Using data from studies defining maintenance energy and protein requirements, llamas and alpacas have lower energy and protein requirements compared to other ruminants; however, they have a greater protein requirement per unit of energy. This is consistent with observed differences in urea and glucose metabolism between camelids and other ruminants suggesting a reliance on protein catabolism to maintain blood glucose concentrations. Evidence suggests llamas and alpacas may have a greater requirement for Vitamin D, but no other evidence of significant differences in requirements between camelids and other ruminants. There are limited data defining other nutrient requirements or differences in requirements based on physiologic state for llamas and alpacas. In spite of limited data, a factorial approach to estimate nutritional requirements of llamas and alpacas was described. Defined maintenance energy and protein requirements were extrapolated to other physiologic states using beef cattle, sheep and goat data as templates. Models were developed to predict energy, protein, mineral and vitamin requirements for growth, pregnancy and lactation. Model development was based on determining beef cattle and sheep nutrient requirements on an amount per kg of body weight and assuming no inherent metabolic differences among species. An averaged value was calculated and used as a basis for defining requirements for llamas and alpacas. Amount per kg body weight requirements were converted to a recommended dietary nutrient density basis using an observed lower dry matter intake per unit body weight. Factorially derived models were in better agreement with North American feeding recommendations compared to predicted requirements using current North American-based requirement models. North American-based requirement equations over predicted energy and protein, resulting in required dietary nutrient densities in excess of practical feeding practices. The proposed factorial models need to be critically validated, but provides a starting point for discussion in advancing the study and application of llama and alpaca nutrient requirements. There are tremendous gaps in our knowledge of llama and alpaca requirements, requiring further basic research especially in the areas of neonatal and fetal growth and composition, lactational performance and mineral bioavailability.
(10-March-2006)
 

Tanaka DL, Karn JF, Liebig MA, Kronberg SL, Hanson JD (2006) An integrated approach to crop/livestock systems: Forage and grain production for swath grazing Renewable Agriculture and Food Systems 20 (4): 223-231

KEYWORDS: no-till; corn; triticale; oat/pea; farming systems; sustainable agriculture; crop; diversity

SUMMARY: Current agricultural systems are the result of decoupling crop/livestock enterprises for short-term economic gain at the expense of long-term sustainability. Objectives of our research were to determine the influences of winter grazing dry gestating beef cows on no-till forage and grain production, water-use efficiency, and protein and phosphorus (P) production for an oat/pea-triticale/sweet clover-corn 3-year cropping system. Oat/pea and triticale crops were harvested for grain, with the straw and chaff left in swaths after harvest for winter grazing. Drilled corn for forage was swathed in late September. Cropping system treatments were: (1) straw and corn chopped and left in place (IP); (2) straw and corn baled and removed without livestock (R); and (3) straw and corn swath grazed by livestock (L). The first winter for grazing dry, bred cows was in 1999-2000; therefore, no treatment differences occurred for the 1999 crop. In 2000, oat/pea and triticale grain and straw production for the IP treatment was about half of the production for the R treatment, because of low oat/pea and triticale plant stands on the IP treatment. Averaged over all years, corn was about 1.5 times more efficient in using water for dry matter production when compared to oat/pea or triticale. Generally, protein and P production, on a unit area basis, were highest for corn and lowest for triticale. Averaged over 4 years, about half of the nitrogen used for protein production was derived from sources other than applied commercial fertilizer. Data suggest that more than 4 years of research are needed to understand cropping system and animal interactions on forage and grain production in integrated crop/livestock systems, with trends in year four suggesting that livestock may enhance forage and grain production.
(10-March-2006)
 

Pinos-Rodriguez JM, Gonzalez S, Mendoza G, Garcia JC, Miranda L, De La Cruz GA, De Lerma V (2005) Effect of exogenous fibrolytic enzymes on in vitro dry matter disappearance of foodstuffs, and on milk yield of Holstein cows Interciencia 30 (12): 752-757 (Spanish)

KEYWORDS: alfalfa medicago-sativa; dairy-cows; digestive characteristics; lolium-perenne; dietary fiber; feed enzymes; beef steers; cell-wall; digestibility; fermentation

SUMMARY: Exogenous enzyme complexes are used to increase forage fiber digestibility, but their effect on other foodstuffs included in the total mixed ration for ruminants, is not totally understood. A first experiment was performed to evaluate the effect of fibrolytic enzymes on in vitro dry matter disappearance (IVDMD) of energetic (corn and sorghum grain), proteinic (soybean meal, cotton seed hull and concentrate), fibrous (soybean hulls and corn silage) and alfalfa hay (7, 12, 2 1 y 28 days from budding) foodstuffs, incubated for 3, 6, 12, 24, 48 and 72h. Enzymes increased (P<0.10) IVDMD of fibrous foodstuffs. In the second experiment, the effect of fibrolytic enzymes on milk production of Holstein cows fed with total mixed rations prepared with the same foodstuffs used in the first experiment, was determined. Milk production for weeks 3, 4, 8 (P<0.10) and 5, 16 (P<0.05) was increased by effect of exogenous fibrolytic enzymes.
(10-March-2006)
 

Ware RA, Zinn RA (2005) Effect of pelletizing on the feeding value of rice straw in steam-flaked corn growing-finishing diets for feedlot cattle Animal Feed Science And Technology 124 (3-4): 631-642

KEYWORDS: pellet; pelletized; rice straw; cattle; subacute ruminal acidosis; neutral detergent fiber; volatile fatty-acids; lactating dairy-cows; rumen fermentation; sodium propionate; net carbohydrate; protein system; barley straw; beef steers

SUMMARY: Trial 1. Three cannulated crossbred steers were used to compare the effects of ground versus pelletized rice straw on characteristics of digestion. Treatments consisted of a steam-flaked corn-based diet containing 120 g/kg sudangrass (SG, positive control), ground rice straw (GAS) or pelletized rice straw (PRS). Ruminal digestion of organic matter was similar across treatments (P < 0.10). Run-final digestion of neutral detergent fiber was low, averaging 140 g/kg, and not affected (P > 0.10) by forage source. Ruminal starch digestion was lower (5%; P < 0.05) for sudangrass than for rice straw diets, and greater (8%, P < 0.01) for pelletized versus ground straw. Ruminal microbial efficiency was greater (9.7%; P < 0.05) for ground than for pelletized rice straw. Total tract digestion of dry matter was greater (3%, P < 0.10) for sudangrass than for rice straw treatments and NDF digestion was lower (26%; P < 0.05) for rice straw than for sudangrass diets. Total tract starch digestion was greater (2%, P < 0.01) for pelletized than for ground rice straw diets, due largely to greater ruminal starch digestion. Treatment effects were numerically similar for ground sudangrass and ground rice straw diets. Pelletized rice straw increased (P < 0.05) ruminal total volatile fatty acid (VFA) and propionate concentrations by 24 and 47% respectively, and decreased ruminal pH (9%, P < 0.05), ruminal acetate:propionate molar ratio (27%, P < 0.05), and estimated methane production (28%, P < 0.05). Trial 2. Ninety crossbred yearling steers were used in a 112 day finishing trial to evaluate the influence of pelletizing on the feeding valueof rice straw. Treatments were the same as Trial 1. Substituting ground rice straw for sudangrass had no detrimental effects (P > 0.10) on energy intake or average daily gain (ADG). However, DMI and ADG were greater (11%, P < 0.05, and 12%, P < 0.10, respectively) for ground than for pelletized rice straw supplemented diets. There were no treatment effects (P < 0.10) on dressing percentage, which had a carcass to live weight ratio averaging 0.642. Steers fed the sudangrass diet had a lower yield grade (16%; P < 0.01), marbling score (13%; P < 0.05), and fat thickness (15%; P < 0.10) than those fed the rice straw diets. Feeding pelletized straw reduced marbling score (10%, P < 0.10), and fat thickness (20%; P < 0.10) when compared with ground rice straw. As expected, NEm and NEg were greater (5%; P < 0.01) for sudangrass than for rice straw diets. Pelletizing rice straw did not decrease (P=0.56) the dietary net energy (NE) value of the rice straw supplemented diets. Thus, the difference in ADG due to feeding ground versus pelletized rice straw is attributable solely to treatment effects on DMI. We conclude that at lower levels of rice straw inclusion (< 150g/kg) fed to steers in growing-finishing diets, pelletizing the straw may reduce intake and gain through a satiety response mechanism, possibly associated with increased propionate production.
(10-March-2006)
 

Wina E, Muetzel S, Becker K (2006) The dynamics of major fibrolytic microbes and enzyme activity in the rumen in response to short- and long-term feeding of Sapindus rarak saponins Journal of Applied Microbiology 100 (1): 114-122

KEYWORDS: carboxymethylcellulase; Chytridiomycetes; rumen; Ruminococcus albus; Ruminococcus flavefaciens; Sapindus rarak; xylanase; protozoan polyplastron-multivesiculatum; ruminal bacteria; ciliate protozoa; in-vitro; population structure; wheat-straw; cellulose; fermentation; xylanase; probes

SUMMARY: Aims: To investigate the short- and long-term effects of an extract of Sapindus rarak saponins (SE) on the rumen fibrolytic enzyme activity and the major fibrolytic micro-organisms. Methods and Results: Two feeding trials were conducted. In the short-term trial, four fistulated goats were fed a basal diet containing sugar cane tops and wheat pollard (65 : 35, w/w) and were supplemented for 7 days with SE at a level of 0.6 g kg(-1) body weight. Rumen liquor was taken before, during and after SE feeding. In the long-term trial, 28 sheep were fed the same basal diet as the goats and were supplemented for 105 days with 0.24, 0.48 and 0.72 g kg(-1) body mass of the extract. Rumen liquor was taken on days 98 and 100. Protozoal numbers were counted under the microscope. Cell wall degradation was determined by enzyme assays and the major fibrolytic micro-organisms were quantified by dot blot hybridization. Conclusion: Sapindus extract significantly depressed rumen xylanase activity in both trials and carboxymethylcellulase activity in the long-term trial (P < 0.01). Fibrobacter sp. were not affected by the SE in both trials, while ruminococci and the anaerobic fungi showed a short-term response to the application of saponins. Protozoal counts were decreased only in the long-term trial with sheep. Significance and Impact of the Study: These data suggest that there is an adaptation of Ruminococcus albus, Ruminococcus flavefaciens and Chytridiomycetes (fungi) to saponin when fed over a long period. The fact that no correlation between the cell wall degrading enzyme activities and the cell wall degrading micro-organisms was observed suggests that the organisms tracked in this experiment are not the only key players in ruminal cell wall degradation. Sapindus rarak saponins partially defaunate the rumen flora. Their negative effect on cell wall degradation, however, is not related to rumen organisms currently recognized as the major cell wall degrading species. The adaptation of microbes in the long-term feeding experiment suggests that the results from short-term trial on the ruminal microbial community have to be interpreted carefully.
(10-March-2006)
 

Hu WL, Liu JX, Wu YM, Guo YQ, Ye JN (2006) Effects of tea saponins on in vitro ruminal fermentation and growth performance in growing Boer goat Archives Of Animal Nutrition 60 (1): 89-97

KEYWORDS: Boer goats; growth performance; rumen; fermentation; tea; saponins; yucca-schidigera; nutrient digestion; protein-synthesis; extract; cows

SUMMARY: Two experiments were conducted to investigate the effects of tea saponins (TS) on in vitro ruminal fermentation and growth performance in growing Boer goats. In Experiment 1, the Reading Pressure Technique (RPT) system was used to investigate the effect of addition of TS (0, 0.2, 0.4 and 0.8 mg/ml) on the ruminal fermentation in vitro . The 24 h gas production and methane emission were significantly decreased when 0.4 or 0.8 mg TS was included, suggesting that the TS could inhibit the release of methane. Compared to the control, the TS had little effect on pH values and the concentration of total volatile fatty acids in the ruminal fluids. However, the fermentation patterns were changed, with lower acetate and higher proportions of propionate when TS was added. Ammonia-N concentration and protozoal counts were significantly reduced, while microbial protein yield was increased by the TS addition, suggesting that the TS could modify the ruminal fermentation. In Experiment 2, 27 growing Boer goats were used to evaluate the effects of the TS addition on growth performance. The animals received the same basal diets, and added TS at levels of 0 (C), 3 g (T1) and 6 g (T2) per day. The experiment lasted for 60 days with the first 15 days for adaptation. Blood samples were obtained by jugular venipuncture before the morning feeding on the final day of the experiment. During the whole periods, dry matter intake, average daily gain and feed efficiency in T1 were higher than in the other two. Serum total protein, albumin, high density lipoprotein cholesterol, Ca and P and alkaline phosphatase levels were higher in group T1 than in C and T2, whereas the blood urea nitrogen, creatinine and total cholesterol were lower in the TS-added groups. The concentrations of glucose, glutamic-oxaloacetic transaminase and glutamic-pyruvic transaminase were not affected by the TS. From the results obtained in this study, it is inferred that the TS could modify the ruminal fermentation and that proper doses of TS may have potential in improving the animal growth performance, whereas at high doses, it may have adverse effects on animal production.
(10-March-2006)
 

Trabalza-Marinucci M, Poncet C, Delval E, Fonty G (2006) Evaluation of techniques to detach particle-associated microorganisms from rumen contents Animal Feed Science and Technology 125 (1-2): 1-16

KEYWORDS: rumen bacteria; detachment; N-15; dairy-cows; bacterial fractions; ruminal bacteria; chemical-composition; ruminococcus-flavefaciens; nitrogen supplementation; solid fractions; cellulose; liquid; protozoal

SUMMARY: Effects of the most commonly used treatments to detach particle-associated microorganisms from rumen contents were investigated using rumen particles of different sizes. Particles were obtained before feeding from ruminally carmulated sheep. The extent of microorganism dissociation was determined using N-15 as an external marker. The first experiment studied the effect of anaerobiosis on efficiency of 1 g/l methylcellulose, pH 8, and chilling (4 degrees C). Due to poor detachment, the anaerobic procedure was discarded. The following factors, separately or in combination, were then examined in aerobic conditions on two classes of particles obtained from whole ruminal contents (large: > 400 mu m; small: 100-400 mu m) being: (a) stomacher pummelling (5 min); (b) Waring blender homogenisation (3 x 1 min); (c) chilling (4 degrees C); (d) pH 8; (e) 1 g/l methylcellulose; (f) 10 ml/l methanol and 10 ml/l tertiary butanol. Samples were incubated for 5 h, except for treatments (a) and (b), and washed after treatment for 2 min under running tap water in a 25 mu m gauze. Blending proved to be the most effective treatment (from 50 to 57% removal). Combinations of treatments did not improve detachment. N losses from treated samples were linearly related to N-15 removal. The percentage of particles removed was calculated using incubated and/or washed particles as the control, according to treatments. Results suggest that caution is needed when evaluating the effectiveness of treatments, because results are dependent on the type of particles chosen as the control.
(10-March-2006)
 

Rotger A, Ferret A, Calsamiglia S, Manteca X (2006) In situ degradability of seven plant protein supplements in heifers fed high concentrate diets with different forage to concentrate ratio Animal Feed Science and Technology 125 (1-2): 73-87

KEYWORDS: heifers; high concentrate diets; in situ nitrogen degradability; plant protein supplements; dry-matter; intestinal degradability; microbial fermentation; nitrogenous compounds; insitu evaluation; ph fluctuations; basal diet; digestion; rumen; degradation

SUMMARY: Four Holstein heifers (297.5 +/- 27.7 kg BW) fed high concentrate diets were used in a crossover experiment in order to characterize the rumen fermentation pattern, and to estimate by the in situ method rumen degradation kinetics of alfalfa hay and seven plant protein supplements: solvent-extracted soybean meal, solvent-extracted sunflower meal, peas (Pisum sativum L.), lupin seeds (Lupinus sp.), broadbean (Vicia faba L.), horsebean (Vicia faba L. var equina) and vetch (Vicia sativa L.), in high concentrate diets with different forage to concentrate ratio. Heifers were fitted with a ruminal cannula. The experiment was performed in two 30-day periods, 15 days of diet adaptation and 15 days of sampling. At each period, heifers were offered one of two total mixed rations (12:88 versus 30:70 forage to concentrate ratio), two heifers per diet, on ad libitum basis. After the first period, heifers switched treatments. Intake of dry matter (DM), organic matter, crude protein and neutral detergent fibre (NDF), expressed as kg/day, did not differ between treatments, but DM intake, expressed as g/kg metabolic body weight (BW), was higher in the 12:88 diet. Average rumen pH was 6.0 in both diets, and the time pH was below 5.8, which is considered as a critical threshold for fibre degradation, was the same for both treatments (10.4 +/- 1.6 h). Average ammonia nitrogen and volatile fatty acid (VFA) concentrations did not differ between treatments and individual VFA proportions were typical of high concentrate diets. Average effective degradability of DM (0.62 +/- 0.02) and NDF (0.25 +/- 0.03) of alfalfa hay were low and no differences were detected between treatments. The same extent of NDF degradation, together with the same proportions of VFA would indicate that both diets had the same fibrolytic activity. Forage to concentrate ratio did not affect rumen nitrogen degradability of any protein supplements incubated in situ. Corrected effective degradability for small particle losses of sunflower meal (0.78) was higher than legume seeds, which were not statistically different between each other and ranged from 0.63 to 0.66. Soybean meal had the lowest degradability value (0.61). These nitrogen degradation values must be considered more valid for beef cattle formulation of high concentrate diets than data obtained with forage diets.
(10-March-2006)
 

Muetzel S, Becker K (2006) Extractability and biological activity of tannins from various tree leaves determined by chemical and biological assays as affected by drying procedure Animal Feed Science and Technology 125 (1-2): 139-149

KEYWORDS: tannin; extraction; protein precipitation; in vitro incubation; drying procedure; maillard reaction-products; condensed tannins; in-vitro; calliandra-calothyrsus; endoglucanase activity; lotus-pedunculatus; temperate forages; sericea-lespedeza; gas-production; filter-paper

SUMMARY: Leaf samples of Juglans regia (walnut), Rhus typhina (sumach), Aesculus hippocastanum (chestnut) and Salix alba (willow) were either freeze dried or oven dried and the amount of tannins was determined by two chemical assays (Folin Ciocalteau and ferric chloride method). In addition, the biological activity of these tannins was determined by their protein precipitation capacity and by a bioassay based on the incubation to the leaves in vitro in buffered rumen fluid with and without polyethylene glycol. Generally, oven drying is recognised to decrease the extractability and/or the biological activity of tannins. Our results however do not indicate a general decrease in extractability of tannins due to oven drying. The effects observed were plant specific with negative effects of oven drying in walnut and willow leafs, positive effects in chestnut leaves and no effects were observed for the sumach. No negative effects of oven drying were detected for the biological activity of the tannins. The specific protein precipitation capacity was nearly identical for the freeze dried and the oven dried tannins. Oven drying however decreased the solubility of the cell contents and the plant cell wall, which led to changes in fermentation end products, but the biological activity of the tannins was not negatively affected by the oven drying. Although some differences in the extractability and activity of the individual plant species were observed, we conclude from this work that the drying procedure has no negative effect on the biological activity of the tannins examined.
(10-March-2006)
 

Casler MD, Jung HJG (2006) Relationships of fibre, lignin, and phenolics to in vitro fibre digestibility in three perennial grasses Animal Feed Science And Technology 125 (1-2): 151-161

KEYWORDS: smooth bromegrass; cocksfoot; reed canarygrass; lignin; ferulate; p-coumarate; smooth bromegrass clones; neutral detergent fiber; forage cell-walls; klason lignin; animal nutrition; dietary fiber; dry-matter; selection; polysaccharides; residues

SUMMARY: Livestock performance can be improved by increasing the digestibility of feeds, one of the key elements of nutritional quality. Digestibility of feeds can be improved by breeding forage crops with modified cell-wall structure, increasing the potential availability of energy from the cell wall to rumen microbes and livestock. The objectives of this research were to identify interrelationships among lignin and phenolic components of the fibre fraction of three perennial grasses and to determine their influence on in vitro fibre digestibility. Differences in etherified and esterified ferulate and esterified p-coumarate among clones of three perennial grasses were generally repeatable across harvests. The concentration of neutral detergent fibre (NDF) and Klason lignin within the NDF fraction were the factors most limiting to 24-h in vitro digestibility, with NDF being the most important. Klason lignin and etherified ferulate were the factors most limiting to 96-h in vitro digestibility for all three species. Due to its positive correlation with NDF, selection for low etherified ferulate should be avoided in smooth bromegrass (Bromus inermis Leyss) and cockfsoot (Dactylis glomerata L.). It should be possible to select and breed for low concentrations of lignin to improve digestibility without decreasing NDF in these two species. However, in reed canarygrass (Phalaris arundinacea L.), both lignin and etherified ferulate were positively correlated with NDF, indicating that selection for increased digestibility should be based directly on some measure of in vitro digestibility to avoid the fitness problems associated with reduced NDF.
(10-March-2006)
 

Landau S, Glasser T, Dvash L (2006) Monitoring nutrition in small ruminants with the aid of near infrared reflectance spectroscopy (NIRS) technology: A review Small Ruminant Research 61 (1): 1-11

KEYWORDS: goat; sheep; deer; feed spectra; fecal spectra; fecal nirs; grass-silage; botanical composition; chemical-composition; rumen degradation; forage quality; crude protein; maize silages; diet quality; prediction

SUMMARY: This review aims to evaluate the contribution of near infrared reflectance spectroscopy (NIRS) to monitor nutrition in small ruminants, with particular emphasis on the use of feed spectra and fecal spectra. NIRS provides satisfactory accuracy in the analysis of the chemical constituents of feeds for small ruminants, e.g., crude protein and cell wall composition, and is sometimes better than in vitro procedures for predicting in vivo digestibility and the available energy in feeds. In addition, in vitro digestibility can be accurately estimated by NIRS. The effective rumen degradability of protein could potentially be accurately predicted by NIRS, which would eliminate the need for rumen-fistulated animals. Good accuracy in the prediction of tannins has been reported for narrow, single-species applications, as well as for broad arrays of browse species. The identification of NIR segments corresponding to undigested entities has potential to help in providing spectral markers of digestibility. Fecal output can easily be evaluated, using the NIRS-aided analysis of polyethylene glycol (PEG) administered as external indigestible marker. Analysis of NIR spectra of the feces enables the accurate prediction of the chemical characteristics of the feed (dry matter digestibility and crude protein, cell wall attributes, PEG-binding tannins) in stall-fed and grazing animals, and to some extent, of the botanical composition of diets at pasture. Thus, fecal NIRS methodology holds the potential to provide nutritional diagnoses for farmers raising small ruminant.
(10-March-2006)
 

Aksu T, Baytok E, Karsli MA, Muruz H (2006) Effects of formic acid, molasses and inoculant additives on corn silage composition, organic matter digestibility and microbial protein synthesis in sheep Small Ruminant Research 61 (1): 29-33

KEYWORDS: corn silage; formic acid; molasses; bacterial inoculant; digestibility; microbial protein synthesis; animal performance; fermentation; digestion; grass; forage; rumen

SUMMARY: This study examined the production of com silages with low or high lactic acid concentrations, provided by the addition of formic acid (0.5%), molasses (5%) or microbial inoculant (homofermentative lactic acid bacteria, 10 g/tonne). After the fermentation period, sheep were fed the silages to determine true and apparent digestibility of the organic matter and microbial protein synthesis. The experiments were carried out with four KivircikxMorkaraman sheep, 1.5 years old, fixed with cannula in their rumen and duodenum.
Lactic acid concentrations were significantly higher in silages treated with enzyme or molasses compared to other specific treatments. Acetic acid concentration was highest in silage treated with formic acid, and lowest in silage treated with molasses (P < 0.05). The by-pass of crude protein was highest in silage treated with formic acid.
(10-March-2006)
 

Girard CL, Matte JJ (2005) Folic acid and vitamin B-12 requirements of dairy cows: A concept to be revised Livestock Production Science 98 (1-2): 123-133

KEYWORDS: dairy cow; lactation; folic acid; vitamin B-12; rumen-protected methionine; methyl-group metabolism; fed dietary-supplements; serum folate; plasma homocysteine; milk-fat; deficiency; lactation; disease; performance

SUMMARY: Based on a limited number of research studies conducted on steers, it seems that the supply in folic acid could be limiting based on estimated ruminal synthesis and dietary supply. Folic acid has the single, important biochemical function in mammals to accept and release one-carbon units. This role is essential for the synthesis of purine and pyrimidine and the de novo provision of methyl groups for formation of the primary methylating agent, S-adenosylmethionine. Given its metabolic roles, folic acid is critical for cell division and protein metabolism, and therefore is an ideal candidate to begin with while reviewing B-vitamin requirements of dairy cow for an optimal productivity. Moreover, metabolisms of folic acid and vitamin B-12 are closely linked, utilization of folates by cells being dependent of vitamin B12 Supply. Studies reported in the present paper demonstrate that the supply in these two B-vitamins is not always sufficient to maximize health and productivity of dairy cows. Supplementation in those vitamins, especially during early lactation, improved lactational performance, metabolic efficiency and nutritional quality of milk. However, other research needs to be conducted to overcome the problems caused by the massive destruction of dietary supplements of those vitamins in rumen.
(10-March-2006)
 

Pinotti L, Campagnoli A, Dell'Orto V, Baldi A (2005) Choline: Is there a need in the lactating dairy cow? Livestock Production Science 98 (1-2): 149-152

KEYWORDS: dairy cows; choline; rumen-protected choline; essential nutrient; alpha-tocopherol; milk-production; vitamin-e; metabolism; humans

SUMMARY: Recent developments in nutrition have established that choline is an essential nutrient for mammals when a sufficient supply in methionine and folates is not available in the diet. Vitamin B 12 is also involved in this process. In adult ruminants, choline is extensively degraded in the rumen; for this reason dietary choline contributes insignificantly to the choline body pool and methyl group metabolism is generally conservative with a relatively low rate of methyl catabolism and an elevated rate of de novo synthesis of methyl groups via the tetrahydrofolate system. In dairy ruminants, the dietary availability of choline is nearly non-existent, but the output of methylated compounds in milk is high while methionine as well as other sources of methyl groups are likely to be in short supply, especially at the onset of lactation. Based on those observations, the effects of rumen-protected choline (RPC) supplementation to transition cows was studied in two trials. Results obtained suggested that a greater choline availability can improve not only milk production efficiency, but also lipid and methyl group metabolism in transition dairy cows. RPC also increased plasma alpha-tocopherol, suggesting a novel choline-vitamin E interaction. However, the exact mechanisms underlying these findings are unclear, and choline requirements in dairy cows are still unknown. This indicates that further studies under different feeding conditions are needed.
(10-March-2006)
 

Aferri G, Leme PR, Silva SDE, Putrino SM, Pereira ASC (2005) Performance and carcass characteristics of steers fed different fat sources Revista Brasileira de Zootecnia-Brazilian Journal of Animal Science 34 (5): 1651-1658 (in Portuguese)

KEYWORDS: calcium salt of fatty acids; carcass dressing; fat thickness; feedlot; rib eye area; whole cottonseed; cattle; diets; rumen; acids; biohydrogenation; metabolism; cottonseed; silage; urea

SUMMARY: The objective of this trial was to evaluate the animal performance, carcass characteristics and meat tenderness of 36 crossbred steers averaging 14 months old and 320 kg body weight. The animals were fed high concentrate-based diets: control-without additional fat (CO); diet with 5% calcium salt of fatty acids (AG); and diet with 21% whole cottonseed (CA). Dry matter intake of AG treatment was lower (P=0,05)than CA, that differ from CO diet. No significant differences of treatments on daily weight gain and feed efficiency were observed. Blood urea nitrogen was greater (P=0,01) for CA treatment than AG treatment. Carcass dressing, rib eye area, fat thickness, kidney and pelvic fat, liver weight, pH and temperature did not show significant difference. No difference on water loss during cooking and tenderness measured by shear force at different aging times was detected. Diets with 5% calcium salt of fatty acids or 21% whole cottonseed can be used for feedlot with no change on animal performance or carcass characteristics.
(10-March-2006)
 

de Oliveira MVM, Lana RD, Jham GN, Pereira JC, Perez JRO, Valadares SD (2005) Effects of different dietary levels of monensin and protein on intake and ruminal fermentation in bovines Revista Brasileira de Zootecnia-Brazilian Journal of Animal Science 34 (5): 1763-1774

KEYWORDS: ammonia; ionophore; ruminant; volatile fatty acid; winter-wheat pasture; dairy-cows; nitrogen-utilization; rumen fermentation; digestive function; concentrate diets; artificial rumen; feedlot cattle; steers; performance

SUMMARY: Four ruminally fistulated Holstein steers were fed four times a day (8 a.m., 11 a.m., 2 p.m. and 5 p.m.) with four diets with low and high protein content, with or without monensin, to verify the effect of monensin on feed intake and ruminal fermentation. Diets contained (dry matter basis): low(11.4%) and high (16.5%) crude protein content, 65% of brachiaria hay (Brachiaria decumbens) and 35% of concentrate. Corn and urea- and corn and soybean meal-based diets were, respectively, the concentrates of low and high protein content. The level of ionophore was of 28 mg of monensin/kg of DM intake. Samples of ruminal fluid were collected from the animals two hours post-feeding. The experiment was analyzed as a Latin square with four treatments and four animals. High protein content-based diets increased ruminal concentration of butyric acid and ammonia. Feeding of diets with monensin, independently of the protein content, decreased dry matter intake, increased propionic acid concentration and decreased butyric acid, acetate: propionate ratio and specific activity of ammonia production. Monensin with low protein content-based diet also decreased acetic acid concentration and incerased ruminal pH and microbial protein synthesis. No significant differences on the concentration of ruminal ammonia for diet with monensin were observed.
(10-March-2006)
 

Bannink A, Kogut J, Dijkstra J, France J, Kebreab E, Van Vuuren AM, Tamminga S (2006) Estimation of the stoichiometry of volatile fatty acid production in the rumen of lactating cows Journal of Theoretical Biology 238 (1): 36-51

KEYWORDS: volatile fatty acids; rumen fermentation; lactating cows; ruminal protein-degradation; treated soybean-meal; dairy-cows; small-intestine; amino-acids; nutrient digestion; dietary-protein; calcium salts; holstein cows; grass-silage

SUMMARY: The purpose of this study was to improve the prediction of the quantity and type of Volatile Fatty Acids (VFA) produced from fermented substrate in the rumen of lactating cows. A model was formulated that describes the conversion of substrate (soluble carbohydrates, starch, hemi-cellulose, cellulose, and protein) into VFA (acetate, propionate, butyrate, and other VFA). Inputs to the model were observed rates of true rumen digestion of substrates, whereas outputs were observed molar proportions of VFA in rumen fluid. A literature survey generated data of 182 diets (96 roughage and 86 concentrate diets). Coefficient values that define the conversion of a specific substrate into VFA were estimated meta-analytically by regression of the model against observed VFA molar proportions using non-linear regression techniques. Coefficient estimates significantly differed for acetate and propionate production in particular, between different types of substrate and between roughage and concentrate diets. Deviations of fitted from observed VFA molar proportions could be attributed to random error for 100%. In addition to regression against observed data, simulation studies were performed to investigate the potential of the estimation method. Fitted coefficient estimates from simulated data sets appeared accurate, as well as fitted rates of VFA production, although the model accounted for only a small fraction (maximally 45%) of the variation in VFA molar proportions. The simulation results showed that the latter result was merely a consequence of the statistical analysis chosen and should not be interpreted as an indication of inaccuracy of coefficient estimates. Deviations between fitted and observed values corresponded to those obtained in simulations.
(10-March-2006)
 

Tricarico JM, Johnston JD, Dawson KA, Hanson KC, McLeod KR, Harmon DL (2005) The effects of an Aspergillus oryzae extract containing alpha-amylase activity on ruminal fermentation and milk production in lactating Holstein cows Animal Science 81: 365-374 Part 3

KEYWORDS: Aspergillus oryzae; dairy cows; milk production; starch; dairy-cows; fibrolytic enzymes; degrading enzymes; blood metabolites; fatty-acids; cattle; digestibility; butyrate; performance; starch

SUMMARY: The effects of an Aspergillus oryzae extract containing alpha-amylase activity (Amaize (TM), Alltech Inc., Nicholasville, KY) were examined in vivo and in vitro. A lactating cow study employed 20 intact and four ruminally fistulated Holstein cows in a replicated 4 x 4 Latin-square design to examine the effects of four concentrations of dietary Amaize (TM) extract on milk production and composition, ruminal fermentation and serum metabolite concentrations. The treatment diets contained 0, 240, 480 or 720 alpha-amylase dextrinizing units (DU) per kg of total mixed ration (TMR) (dry-matter basis). The supplemental alpha-amylase increased the yields of milk (P = 0.02), fat (P = 0.02) and protein (P = 0.06) quadratically. The maximum milk yield was obtained when 240 DU per kg of TMR were offered. Ruminal in situ starch disappearance was not affected by alpha-amylase supplementation in lactating cows or ruminally cannulated steers. Supplemental alpha-amylase extract reduced the molar proportion of propionate in the rumen of steers (P = 0.08) and lactating cows (P = 0.04), and in rumen-simulating cultures (P = 0.04). The supplement also increased the molar proportions of acetate (P = 0.06) and butyrate (P = 0.05), and the serum beta-hydroxybutyrate (P = 0.01) and non-esterified fatty acid (P = 0.03) concentrations in lactating cows. The improvements in milk production appear to be a consequence of the effects of alpha-amylase on ruminal fermentation and the potential changes in nutrient metabolism that result from them. We conclude that supplemental alpha-amylase may be given to modify ruminal fermentation and improve milk and component yield in lactating Holstein cattle.
(10-March-2006)
 

Sinclair LA, Cooper SL, Huntington JA, Wilkinson RG, Hallett KG, Enser M, Wood JD (2005) In vitro biohydrogenation of n-3 polyunsaturated fatty acids protected against ruminal microbial metabolism Animal Feed Science And Technology 124 (3-4): 579-596

KEYWORDS: biohydrogenation; fish oil; in vitro; linseed oil; marine algae; conjugated linoleic-acid; fish-oil; rumen degradability; adipose-tissue; dairy-cows; vitamin-e; sheep; supplementation; hydrogenation; digestion

SUMMARY: The objective of this study was to investigate, in vitro, methods of protecting n - 3 polyunsaturated fatty acids from biohydrogenation in the rumen. Linseed oil (LO) was used as a source rich in alpha-linolenic acid (18:311 - 3), and was compared with whole linseed (LS), formaldehyde-treated linseed (FL), formaldehyde-treated linseed that was pre-treated with sodium hydroxide (SFL), formic acid (FFL) or ammonium tetraformate (AFL), xylose treated linseed (XL) or linseed oil absorbed into a fibre source (ALO). Fish oil (FO) was used as an oil rich in eicosapentaenoic acid (20:5n - 3) and docosahexaneoic acid (22:6n - 3), and was compared with fish oil encapsulated with saturated fat (EFa and EFb), marine algae (AG) or fish oil absorbed into a fibre source (AFO). In addition, there was a control (C) with no added oil. The oil sources were incubated using a batch culture technique, and the fermentation terminated after 6, 12, 24 and 48 h. Gas production profiles were similar for the treatments high in 18:3n - 3, whilst the potential extent of gas production was lower (P < 0.01) in FO compared with C, EFa, EFb, AG or AFO. For treatments high in 18:3n - 3, vessel fluid pH decreased (P < 0.001) with time, and was highest (P < 0.001) in C, but did not differ among treatments. Vessel pH also decreased (P < 0.001) with time in treatments high in 20:5n - Sand 22:6n - 3, and was highest (P < 0.001) in C and FO. Biohydrogenation of 18:3n - 3 was extensive in treatments LO, LS, FL,AFL, XL and ALO, with mean values at 48 h of incubation of 966, 974, 919, 897, 874 and 904 g/kg respectively, and was lower (P < 0.001) in SFL and FFL (values at 48 h of 557 and 693 g/kg, respectively). The major biohydrogenation intermediary product in treatments high in 18:3n - 3 was trans 18:1, which was highest at 48 h in treatments LO and LS (P < 0.001). Biohydrogenation of 20:5n - 3, but not 22:6n - 3, increased with time (P < 0.01), and was lowest in AG (P < 0.01). Pre-treatment of linseed using sodium hydroxide or formic acid, followed by formaldehyde treatment, offers the best protection against ruminal microbial biohydrogenation, whilst the degree of biohydrogenation of 22:6n - 3 in marine algae was particularly low.
(10-March-2006)
 

Busquet M, Calsamiglia S, Ferret A, Kamel C (2005) Screening for effects of plant extracts and active compounds of plants on dairy cattle rumen microbial fermentation in a continuous culture system Animal Feed Science and Technology 124 (3-4): 597-613

KEYWORDS: rumen fermentation; plant extracts; protein degradation; essential oils; ruminal microorganisms; yucca-schidigera; amino-acids; nitrogen; monensin; bacteria; ammonia; invitro; protein

SUMMARY: Eight dual-flow continuous culture fermenters were used to study effects of plant extracts (Experiment 1) and active compounds of plants (Experiment 2) on rumen microbial fermentation. Each experiment consisted in two replicated periods of 9 days. Fermenters were fed 95 g dry matter (DM)/day in three feedings of a 600 g/kg (DM basis) alfalfa hay and 400 g/kg concentrate (178 g/kg crude protein, CP; 325 g/kg neutral detergent fibre, NDF diet), and maintained at constant temperature (38.5 degrees C), pH 6.4, and solid (0.05/h) and liquid (0.10/h) dilution rates. Both experiments included a negative control with no extract (CTR) and a positive control with monensin (MON). Treatments in Experiment 1 were: Trigonella foenum graecum, Juniperus oxycedrus, Syzygium aromaticum (CLO), Anethum graveolens, Zingiber officinale, and Melaleuca alternifolia. Treatments in Experiment 2 were: benzyl salicylate, anethol, carvacrol (CAR), cinnamaldehyde (CIN), eugenol, and D-carvone. During the adaptation period (i.e., days 1 through 7), samples for ammonia N and volatile fatty acid (VFA) concentrations were collected 2 h after feeding. On days 8 and 9, samples for VFA (2 h after feeding), and large peptide (LPep), small peptide plus amino acid (SPepAA), and ammonia N concentrations (0, 2, 4, 6 and 8 h after feeding) were also collected. During the adaptation period of Experiments 1 and 2, total VFA and ammonia N concentrations were not affected by treatments. During the first 6 days of fermentation in Experiments 1 and 2, MON resulted in lower acetate and higher propionate proportions compared with CTR. However, these differences disappeared after day 6. On days 6 and 7, CLO in Experiment 1 resulted in lower acetate, and higher butyrate, proportions compared with CTR. On day 7, the proportion of acetate was lower in CIN in Experiment 2 compared with CTR. After the adaptation period, CLO resulted in lower acetate, and higher propionate, proportions compared with CTR. The LPep N concentration was higher in CLO compared with CTR, suggesting that CLO reduced peptidolytic activity of rumen microorganisms. In Experiment 2, the LPep N concentration was lower in CAR, and MON resulted in lower SPepAA N concentrations and higher ammonia N concentrations compared with CTR, suggesting that MON stimulated deamination activity of rumen microorganisms. Results indicate that ruminal microbes may adapt to additives within 7 days. However, some plant extracts modified rumen microbial fermentation patterns and may allow manipulation of ruminal fermentation under current commercial practices.
(10-March-2006)
 

Choi NJ, Imm JY, Oh S, Kim BC, Hwang HJ, Kim YJ (2005) Effect of pH and oxygen on conjugated linoleic acid (CLA) production by mixed rumen bacteria from cows fed high concentrate and high forage diets Animal Feed Science and Technology 124 (3-4): 643-653

KEYWORDS: conjugated linoleic acid; rumen bacteria; diet; pH; aerobic condition; butyrivibrio-fibrisolvens a38; unsaturated fatty-acids; milk-fat; biohydrogenation; increase; fermentation; purification; enrichment; isomers

SUMMARY: Conjugated linoleic acid (CLA) production from linoleic acid (LA) was characterized, in a relationship to biohydrogenation (BH), with mixed rumen bacteria obtained from three cows fed a high concentrate diet (HCD; 630 g/kg) or a high forage diet (HFD; 770 g/kg) for 5 weeks. Mixed rumen bacteria were incubated with LA in a rumen fluid medium under various conditions. Rumen bacteria from cows fed HCD were more active (P < 0.05) in BH than those from cows fed the HFD at most tested pHs. Rumen bacteria from HFD fed cows produced mostly cis-9, trans-11 CLA at pHs higher than 6.2, but those from HCD fed cows produced more (P < 0.05) trans-10, cis-12 CLA than cis-9, trans-11 CLA at lower pHs. Production of cis-9, trans-11 CLA, positively correlated, and trans-10, cis-12 CLA inversely correlated, to pH with rumen bacteria from cows fed both diets (r(2)=0.88). Rumen bacteria from HCD fed cows accumulated about four times more cis-9, trans-11 CLA in aerobic conditions, versus anaerobic conditions, after 1 h of incubation. Overall, trans-10, cis-12 CLA producing rumen bacteria may be more acid-tolerant and aero-tolerant than cis-9, traps-11 CLA producing rumen bacteria.
(10-March-2006)
 

Ulyatt MJ, Lassey KR, Shelton ID, Walker CF (2005) Methane emission from sheep grazing four pastures in late summer in New Zealand New Zealand Journal of Agricultural Research 48 (4): 385-390

KEYWORDS: methane; sheep; pastures; dairy-cows; livestock; alkanes

SUMMARY: Four groups of sheep were grazed on four late summer/autumn pastures: southern North Island summer moist hill country (Ballantrae); good quality perennial ryegrass/white clover dominant pasture in the Manawatu (Aorangi); severe late summer drought pasture in Hawke's Bay (Poukawa); and after drought conditions in Canterbury (Springston). Mature ewes were used at Springston, while young wethers were used at all the other sites. Methane emission from each animal was measured using the sulphur hexafluoride (SF6) tracer technique and feed intake was also determined. The pastures used were chosen for their expected chemical compositions at that time of the year. However, unseasonal rain fell just before the measurements were made at Ballantrae, Aorangi, and Springston. Those three pastures, although different in botanical composition, were similar in chemical composition and dry matter (DM) digestibility. The Poukawa pasture was dead and had low protein, soluble carbohydrate and DM digestibility, and high cell wall content. For the Ballantrae, Aorangi, Poukawa, and Springston pastures respectively, methane emissions were: 19.3, 21.9, 21.4, and 35.2 g/day; 13.8, 12.9, 17.8, and 21.1 g/kg DM intake; and the methane yields (methane energy as a percentage of gross energy intake) were 4.1, 3.9, 5.3, and 6.3%. The results support the view that young wether sheep have a lower methane yield than mature sheep and that methane yield is higher from pastures of poor feeding value.
(10-March-2006)
 

Skillman LC, Evans PN, Strompl C, Joblin KN (2006) 16S rDNA directed PCR primers and detection of methanogens in the bovine rumen Letters in Applied Microbiology 42 (3): 222-228

KEYWORDS: clone libraries; grazing bovine; Methanobrevibacter; methanogens; Methanosphaera; PCR; rumen; phylogenetic analysis; ruminal methanogens; community structure; myristic acid; diversity; archaea; identification; crenarchaeota; hybridization; sequence

SUMMARY: Aims: To assess the diversity of ruminal methanogens in a grazing cow, and develop PCR primers targeting the predominant methanogens. Methods and Results: DNA was extracted from rumen contents collected from a cow grazing pasture. Archaeal 16S rRNA genes were amplified by PCR using two pairs of archaea-specific primers, and clone libraries prepared. Selected clones were sequenced. Phylogenetic analysis revealed that for one primer pair, most sequences clustered with Methanobrevibacter spp. whereas with the other primer pair most clustered with Methanosphaera stadtmanae. One sequence belonged to the Crenarcheota. PCR primers were designed to detect Msp. stadtmanae and differentiate between Mbb. ruminantium and Mbb. smithii and successfully tested. Conclusions: The ruminal methanogens included Mbb. ruminantium, Mbb. smithii, Mbb. thaueri and methanogens similar to Msp.stadtmanae. The study showed that apparent methanogen diversity can be affected by selectivity from the archaea-specific primers used to create clone libraries. Significance and Impact of Study: This study revealed a greater diversity of ruminal methanogens in grazing cows than previously recognized. It also shows the need for care in interpreting methanogen diversity using PCR-based analyses. The new PCR primers will enable more information to be obtained on Msp. stadtmanae and Methanobrevibacter spp. in the rumen.
(10-March-2006)
 

Trinacty J, Krizova L, Hadrova S, Hanus O, Janstova B, Vorlova L, Drakova M (2006) Effect of rumen-protected protein supplemented with three amino acids on milk yield, composition and fatty acid profile in dairy cows Journal of Animal and Feed Sciences 15 (1): 3-15

KEYWORDS: amino acids; protein; rumen protection; dairy cow; lactation; milk; fatty acids; grass-silage diets; abomasal infusions; lactating cows; methionine; lysine; histidine; responses; leucine

SUMMARY: `The objective of this study was to determine the influence of rumen-protected protein supplemented with the amino acids lysine (Lys), methionine (Met) and histidine (His) added either as a powder or in the form of rumen-protected tablets to the rumen of dairy cows on the yield, composition and technological suitability of milk. The experiment was carried out on three lactating Holstein cows with an average weight of 523 kg fitted with ruminal and duodenal cannulas. The experiment was divided into 4 periods of 14 d (10 d preliminary period and 4 d experimental period). In the first period one cow received the tablets (T) and the other two received the non-tableted mixture (C) with the same composition. In the subsequent period the design was opposite. Cows were fed a diet based on maize silage, lucerne hay and a supplemental mixture. Powder or tablets consisted of purified soya-protein HP 300, Lys, Met and His. Average milk yield in C cows was 16.73 kg and was significantly lower than in T cows (17.8 kg; P < 0.05). Protein, fat and lactose contents were unaffected by the treatment. Protein yield was lower (529.5 g/d) in the C than in the T (569.3 g/d; P < 0.05) cows. The increase in milk protein yield in T cows was followed closely by progressive increases in casein content (2.46 vs 2.68%). The content of short- and medium-chain fatty acids was higher and the proportion of C 18: 1, C18:2, C18:30 and C20:1 was lower in the C than in the T (P < 0.05) animals. The proportion of UFA (both MUFA and PUFA) was increased and that of SFA in milk (P < 0.05) was decreased in the T animals. The total SFA:UFA ratio was higher in C compared with T cows (1.89 vs 1.52; P < 0.05).
(10-March-2006)
 

Duan ZY, Yan WJ, Wu YM, Ye JA, Liu JX (2006) Comparison of gas test system based on the syringe with the reading pressure technique Journal of Animal and Feed Sciences 15 (1): 121-129

KEYWORDS: gas production in vitro; syringe system; RPT system; rumen; digestibility; invitro; feeds; fiber

SUMMARY: An investigation was conducted to compare the syringe gas test system with the reading pressure technique (RPT). A series of mixtures of neutral detergent fibre (NDF) and maize starch were incubated using both systems and the ratios (wt/wt) of maize starch in the mixtures were 0, 10.0, 20.0, 25.0, 33.3, 50.0, 55.6, 62.5, 71.4, 83.3 and 100%. The gas production (GP) was recorded at 0, 2, 4, 6, 9, 12, 24, 36, 48 and 72 h. There was no significant difference in potential GP between two systems (corrected to 200 mg substrate basis) (P > 0.05), while the GP at a short time of incubation were lower in the RPT system than in the syringe and the rate constant of GP was significantly higher in the syringe (P < 0.05). However, a strong relationship was observed between the 24 h GP values (GP(24h)) in the syringe system and the RPT, which was described by: GP(24h) for the syringe system (ml) = 1.2628 x GP(24h) for the RTP system (ml) + 6.2592 (R-2=0.9784; P < 0.01; n = 132). It is indicated that the GP(24h) in the two systems can be revised reciprocally and appropriate system could be chosen according to the research objectives and characteristics of both methods.
(10-March-2006)
 

Wang JK, Liu JX, Wu YM, Ye JA (2006) Improvement of organic matter digestibility along with changes of physical properties of rice straw by chemical treatments Journal of Animal and Feed Sciences 15 (1): 147-157

KEYWORDS: rice straw; chemical treatment; physical properties; straw digestion; wheat-straw; hydrogen-peroxide; ruminal bacteria; sodium-hydroxide; mulberry leaves; dietary fiber; in-vitro; sheep; rumen; colonization

SUMMARY: This study was carried out to study the effects of different chemical treatments on physical properties and digestion of rice straw. Rice straw was treated with sodium hydroxide (NaOH) at 15, 30, 45, 60 or 75 g/kg dry matter, ammonia bicarbonate (NH4HCO3) at 30, 60, 90, 120 or 150 g/kg or their combinations (10 or 20 g NaOH/kg and 30, 60 or 90 g NH4HCO3/kg), respectively. The relationship between straw digestion and its physical properties was analysed. Treatment with NaOH increased the volumetric weight (VW), swelling capacity (SC), water-holding capacity (WHC), and in vitro organic matter digestibility (OMD), and decreased specific porosity (SP) of rice straw linearly. Treatment with NH4HCO3 did not significantly affect VW, SC, or SP, but increase OMD linearly and tended decrease WHC. For the combination treatment of NaOH and NH4HCO3, there existed significant interactions on SC, SP and OMD. A significant linear correlation was found between OMD and VW, SC, SP, or WHC, when the data for all treatments were analysed. The accuracy of regression equation could be improved by including multiple physical property parameters. It is inferred that change in all physical properties is indicative of improvement in straw digestion after treatment.
(10-March-2006)
 

Juniper DT, Browne EM, Bryant MJ, Beever DE (2006) Digestion, rumen fermentation and circulating concentrations of insulin, growth hormone and IGF-1 in steers given maize silages harvested at three stages of maturity Animal Science 82: 41-48 Part 1

KEYWORDS: insulin; IGF-1; maize silage; rumen fermentation; somatotropin; steers; pancreatic exocrine secretion; factor-i; plasma-concentrations; nutritional-value; crop maturity; beef-cattle; corn-silage; glucose; starch; infusion

SUMMARY: Advancing maturity of forage maize is associated with increases in the proportion of dry matter (DM) and starch and decreases in the proportions of structural carbohydrates in the ensiled crop. Three maize silages (286 (low, L), 329 (medium, M) and 379 (high, H) g DM per kg fresh weight) plus a concentrate formulated to give isonitrogenous intakes were offered to Holstein-Friesian steers fitted with a cannula in the dorsal sac of the rumen and a 'T' piece cannula in the proximal duodenum in an experiment with a cross-over design that allowed four collection periods. Nutrient flow to the duodenum was estimated using chromium-EDTA. Steers consumed approximately 0.6 kg DM per day less of diet L compared with the other two diets (P=0.026), resulting in less DM being digested (P=0.005) but digestibility did not differ between diets. Similar results were obtained for organic matter. There were no differences between diets in the intake or digestibility of neutral-detergent fibre. Intake, duodenal flow and faecal output of starch were greater for steers offered diets M and H compared with those given diet L (P < 0.05). In all diets rumen digestion contributed to over 90% of total digestion of starch, although rumen digestibility declined significantly with advancing maize maturity (P=0.002). Molar proportions of acetic acid were higher in diet H (P < 0.05) whilst proportions of propionic acid and n-butyric acid were higher in diets M and L. There were no significant differences between diets in mean rumen pH or ammonia concentrations. Mean circulating concentrations of insulin were higher (P=0.009) in cattle given diets L and M compared with diet H. There were no differences between diets in the mean circulating concentration of growth hormone, or the frequency, amplitude and duration of growth hormone pulses, or the mean circulating concentrations of IGF-1. Changes in forage composition that accompany advancing maize maturity affect overall silage digestion and circulating concentrations of insulin.
(10-March-2006)
 

Cardinault N, Doreau M, Poncet C, Noziere P (2006) Digestion and absorption of carotenoids in sheep given fresh red clover Animal Science 82: 49-55 Part 1

KEYWORDS: absorption; carotenoids; digestion; sheep; beta-carotene; adipose-tissue; vitamin-a; fatty acids; in-vitro; blood; cattle; grass; rumen; goats

SUMMARY: Digestion and absorption of carotenoids were studied in sheep given, twice daily, fresh red clover. Digestive fluxes were measured in six sheep cannulated in the rumen, duodenum and ileum using the double marker technique. Another five sheep were fitted with catheters allowing nutrient net flux measurements across the portal-drained viscera. Carotenoids in the red clover consisted of lutein (136 mu g/g dry matter (DM)), epilutein (40 mu g/g DM), trans-beta-carotene (16 mu g/g DM) and 13-cis-beta-carotene (13 mu g/g DM). Intake was 174, 52, 21 and 17 mg/day, and faecal excretion was 181, 25, 50 and 41 mg/day, for lutein, epilutein, trans- and 13-cis-beta-carotene respectively, indicating net production of beta-carotene in the digestive tract. The difference between duodenum and intake was positive for all carotenoids (30, 4, 43 and 37 g for lutein, epilutein, trans-beta-carotene and 13-cis-beta-carotene, respectively) suggesting net production and/or release of carotenes and xanthophylls by rumen microbes. Apparent digestibility in the small and large intestines was 0.18 and -0.05 for lutein, 0.30 and 0.29 for epilutein, 0.39 and 0.26 for trans-beta-carotene, 0.53 and 0.21 for 13-cis-beta-carotene. Only lutein and epilutein were recovered in arterial plasma, at a concentration of 14.3 and 10.8 mu g/l, respectively. Their portal net appearance was not different from 0, suggesting that absorption occurred mainly via the lymphatic system.
(10-March-2006)
 

Gonzalez J, Faria-Marmol J, Rodriguez CA, Ouarti M, Alvir MR, Centeno C (2006) Protein value for ruminants of a sample of whole cottonseed Animal Science 82: 75-81 Part 1,

KEYWORDS: amino acids; cottonseed; crude protein; digestibility; rumen fermentation; amino-acid-composition; intestinal digestibility; dairy-cows; rumen degradability; crude protein; in-situ; fractions; incubation; profile; lucerne

SUMMARY: The effective ruminal degradability (ED) of dry matter (DM), crude protein (CP) and amino acids, and the effective intestinal digestibility (IED) of DM and CP of a sample of whole cottonseed was measured using in situ and rumen outflow rate techniques in three wethers cannulated in the rumen and duodenum. The microbial contamination of rumen incubated residues was corrected by a continuous rumen infusion of (NH3)-N-15 as microbial marker and rumen solid associated bacteria as reference sample. Microbial contamination resulted in an overestimation of the undegradable fraction of DM (0.291 v. 0.275; P < 0.05) and CP (0.071 v. 0.037; P < 0.01) and a small underestimation of ED of DM (0.500 v. 0.512; P=0.09) and CP (0.755 v. 0.779; P=0.052). A proportion of 0.1 of the ruminal undegraded CP was of microbial origin and for essential amino acids this proportion varied from 0.042 to 0.150. Differences in ED between amino acids modified the amino acid profile, with an important reduction (0.2; P < 0.01) in the proportion of lysine. Apparent intestinal digestibility of the insoluble fraction of this food, measured with the mobile nylon bag technique, showed large reductions (P < 0.001) with the increase of the ruminal incubation time between 0 and 72 h: from 0.392 to 0.026 for DM and from 0.851 to 0.099 for CP. These evolutions fitted an exponential function with a previous lag. The IED was estimated either by integration of these equations and those describing the ruminal degradation and rumen outflow or by incubation through the intestines of a sample pooled to be representative of rumen flow of the undegraded food. The two methods gave similar values for both DM (0.222 v. 0.203) and CP (0.659 v. 0.658).
(10-March-2006)
 

Cabritaa ARJ, Dewhurst RJ, Abreu JMF, Fonseca AJM (2006) Evaluation of the effects of synchronising the availability of N and energy on rumen function and production responses of dairy cows - a review Animal Research 55 (1): 1-24

KEYWORDS: dairy cow; energy; nitrogen; rumen; synchrony; microbial protein-synthesis; receiving grass-silage; ruminal fermentation; feeding frequency; milk-production; lactating cows; crude protein; amino-acids; continuous-culture; nitrogen release

SUMMARY: This paper reviews the effects of synchronising the availability of N and energy on rumen function and production responses of lactating dairy cows. The paper makes a key distinction between altering the synchronicity of diets by changing dietary ingredients, or by altering the feeding frequency or the feeding patterns. Manipulating synchrony by changing dietary ingredients presents some problems, since it is not possible to discount the possibility that apparent effects of synchrony are associated with the manipulation of the ingredients ( level and type) themselves. These problems can be overcome, at least partially, by altering the feeding patterns. This review shows that the evidence for the benefits of synchronising energy and N supply to the rumen is contradictory, both for efficient microbial protein synthesis and for maximising milk production responses.
(10-March-2006)
 

Machmuller A (2006) Medium-chain fatty acids and their potential to reduce methanogenesis in domestic ruminants Agriculture Ecosystems & Environment 112 (2-3): 107-114 Sp. Iss. SI

KEYWORDS: enteric methane emission; methane mitigation strategy; coconut oil; myristic acid; lauric acid; rumen archaea; greenhouse-gas emissions; methane suppression; coconut oil; dietary-fat; dairy-cows; in-vitro; antibacterial activity; rumen fermentation; energy-balance; myristic acid

SUMMARY: In the wave of the Kyoto Protocol, a large effort is undertaken to find sustainable strategies for reducing greenhouse gas emissions from livestock. The present paper summarises the results of a research project, which was designed to analyse the potential of medium-chain fatty acids (MCFA) as a diet component for ruminants to inhibit rumen methanogenesis. In a series of eight in vitro and four in vivo experiments, a research strategy was pursued including: (i) a comparison of feeding coconut oil (rich in MCFA) and feeds containing long-chain unsaturated fatty acids (LCFA) with respect to their effects on rumen and total digestive tract metabolism; (ii) a search for effective MCFA feeds other than coconut oil; (iii) identification of specific MCFA effective against rumen methanogenesis; (iv) clarification of the mode of action of MCFA; and (v) revealing of dietary pre-conditions for a significant methane-suppressing effect of MCFA. The project clearly demonstrated the potential of MCFA, used either in esterified form (such as coconut oil, palm kernel oil and genetically modified canola oil) or in non-esterified form (C12:0 and C14:0), to substantially reduce methanogenesis in domestic ruminants. Detailed insight into the numerous interactions within the rumen, which will determine the extent of methanogenesis inhibition when feeding MCFA, was gained. From an assessment of the combined data, it was concluded that even with dietary proportions below 3% MCFA of C12:0 and C14:0, a 50% reduction of in vivo methane emission is possible. (c) 2005 Elsevier B.V. All rights reserved.
(10-March-2006)
 

Cho SJ, Cho KM, Shin EC, Lim WJ, Hong SY, Choi BR, Kang JM, Lee SM, Kim YH, Kim H, Yun HD (2006) 16S rDNA anaysis of bacterial diversity in three fractions of cow rumen Journal Of Microbiology And Biotechnology 16 (1): 92-101

KEYWORDS: rumen; bacteria; molecular diversity; 16S rDNA; phylogeny; ribosomal-rna genes; sequence-analysis; phylogenetic analysis; ruminal bacteria; primers; ecology; identification; microbiology; degradation; sediments

SUMMARY: The bacterial diversity of the bovine rumen was examined using a PCR-based approach. 16S rDNA sequences were amplified and cloned from three fractions of rumen (solid, fluid, and epithelium) that are likely to represent different bacterial niches. A total of 113 clones were sequenced, and similarities to known 16S rDNA sequences were examined. About 47.8% of the sequences had 90-97% similarity to 16S rDNA database sequences. Furthermore, about 62.2% of the sequences were 98-100% similar to 16S rDNA database sequences. For the remaining 6.1%, the similarity was less than 90%. Phylogenetic analysis was also used to infer the makeup of the bacterial communities in the different rumen fractions. The Cytophaga-Flexibacter-Bacteroides group (CFB, 67.5%), low G+C Gram-positive bacteria (LGCGPB, 30%), and Proteobacteria (2.5%) were represented in the rumen fluid clone set; LGCGPB (75.7%), CFB (10.8%), Proteobacteria (5.4%), high G+C Gram-positive bacteria (HGCGPB, 5.4%), and Spirochaetes (2.7%) were represented in the rumen solid clone set; and the CFB group (94.4%) and LGCGPB (5.6%) were represented in the rumen epithelium clone set. These findings suggest that the rumen fluid, solid, and epithelium support different microbial populations that may play specific roles in rumen function.
(10-March-2006)
 

Abel H, Schroder B, Lebzien P, Flachowsky G (2006) Effects of defaunation on fermentation characteristics and biotin balance in an artificial rumen-simulation system (RUSITEC) receiving diets with different amounts and types of cereal British Journal Of Nutrition 95 (1): 99-104

KEYWORDS: biotin; protozoa; RUSITEC; b-vitamins; metabolism; steers; grain

SUMMARY: Biotin is required by rumen microbes for efficient fermentation. To evaluate the role of protozoa in ruminal biotin metabolism, five diets composed of grass hay or of grass hay/cereal grain mixtures were supplied to faunated or defaunated RUSITEC fermenters. In the mixed diets, hay was replaced to 33:67 or 67:33 w/w on an air-dried basis by either wheat or maize grain in order to simulate different cellulolytic and amylolytic fermentation conditions. Defaunation increased SCFA production, whereas NH4 concentration and the release of CH4 were reduced. Biotin input declined when cereal grain was used to replace the hay. With the exception of the high-wheat treatment, defaunated fermenters yielded higher biotin outputs than faunated fermenters. The biotin balance, calculated as the difference between the total biotin output (biotin in the solid residue contained in the nylon bags after fermentation plus the biotin in the effluent) and the biotin input with the feed, was negative for all the dietary treatments apart from fermenters supplied with the high-maize diet. It was less negative or, in the case of the high-maize diets, more positive for defaunated compared with faunated fermenters. It was concluded that, under normal faunated conditions, protozoa directly utilise or indirectly affect the bacterial synthesis and/or utilisation of biotin. With diets of a high fermentation potential, as realised with the high-wheat diet, protozoa prevent the development of a bacterial population that would utilise high or synthesise low amounts of biotin.
(10-March-2006)
 

Khampa S, Wanapat M, Wachirapakorn C, Nontaso N, Wattiaux MA, Rowlison R (2006) Effect of levels of sodium DL-malate supplementation on ruminal fermentation efficiency of concentrates containing high levels of cassava chip in dairy steers Asian-Australasian Journal of Animal Sciences 19 (3): 368-375

KEYWORDS: sodium DL-malate; rumen fermentation; microbial protein synthesis; urea-treated rice straw; dairy steers; ruminant; malic-acid; in-vitro; microorganism fermentation; saccharomyces-cerevisiae; chemical-composition; milk-production; rice straw; rumen; protein; diets

SUMMARY: Four rumen-fistulated dairy steers were randomly assigned according to a 4-4 Latin square design to investigate effects of supplementation levels of sodium dl-malate in concentrates on rumen ecology, ruminal fermentation. nitrogen balance, Iced intake and digestibility of nutrients and ruminal microbial protein synthesis. The dietary treatments were cassava concentrate-based, containing sodium dl-malate supplementation at 0, 9, 18 and 27 g/hd/d with urea-treated rice straw (UTS) fed ad libitum I fie experiment was conducted for four periods. each period lasting 21 days. Ruminal pH increased with incremental addition of malate (p < 0.05). Additionally. molar proportions of propionate were higher in supplemented groups and was highest at 18 g/hd/d of malate Supplement (p < 0.05). Microbial protein synthesis tended to be higher in dairy steers receiving sodium di-malate supplements and also was the highest at 18 g/hd/d. Variable bacterial populations, such as amylolytic, proteolytic and cellulolytic species were increased (p < 0.05). Furthermore, protozoal populations were decreased significantly (p < 0.05). while fungal zoospores were dramatically increased in dairy steers receiving sodium dl-malate supplement (p < 0.05), These results suggested that supplementation of concentrate containing a high level of cassava chip at 18 g/hd/d with UTS in dairy steers could improve rumen fermentation efficiency and rumen microbial protein synthesis.
(10-March-2006)
 

Bhatta R, Tajima K, Kurihara M (2006) Influence of temperature and pH on fermentation pattern and methane production in the rumen simulating fermenter (RUSITEC) Asian-Australasian Journal of Animal Sciences 19 (3): 376-380

KEYWORDS: temperature; pH; rumen fermentation; volatile fatty acids; methane; RUSITEC; bacteria; degradation; fiber; sheep

SUMMARY: An experiment was conducted to study the effect of temperature and pH on in vitro nutrient degradability, volatile fatty acid profile and methane production. The fermenter used was the semi-continuous, system, known as the rumen stimulation technique (RUSITEC). Sixteen cylinders were used at one time with a volume of 800 ml, the dilution rate was set at 3.5%/hour, the infused buffer being McDougall's artificial saliva. Basal diet (9.6 g DM) used in RUSITEC consisted of (DM) 6.40 g Timothy hay, 1.86 g crushed corn and 1.34 g soybean meal. The food for the fermentation vessel was provided in nylon bags. Much were gently agitated in the liquid phase, The experiment lasted for 17 d with all the samples taken during the last 5 d. Treatments were allocated at random to four vessels each and were (1) two temperature levels of 39 degrees C and 41 degrees C (2) two pH levels of 6,0 and 7.0. The total diet contained (g kg(-1) DM) 957 OM. 115 CP and 167 MJ kg(-1) (DM) GE, Although increase in temperature from 39 degrees C to 41 degrees C reduced degradation of major nutrients in vitro, it was non-significant. Interaction effect of temperature with pH also reflected a similar trend. However, pH showed a significant (p < 0.05) negative effect on the degradability of all the nutrients in vitro. Altering the in vitro pH from 7 to 0 caused marked reduction in DMD from 60.2 to 41.8, CPD from 76.3 to 55.3 and GED trom 553 to 35, 1, respectively. Low pH (6) depressed total VFA production (61.9 vs. 34.9 mM) as well as acetate to propionate ratio in vitro (from 2.0 to 1.5) when compared to pH 7. Compared to pH 7, total gas production decreased from 1,841 ml to 1,148 ml at pH 6, CO2 and CH4 production also reduced from 639 to 260 ml and 138 to 45 ml. respectively. This study supported the premise that pH is one of the principal factors affecting the microbial production of volatile fatty acids and gas. Regulating the ruminal pH to increase bacterial activity may be one of the methods to optimize VFA production, reduce methane and possibly, improve animal performance.
(10-March-2006)
 

Xu GZ, Ye J, Liu JX, Yu YY (2006) Effect of rumen-protected choline addition on milk performance and blood metabolic parameters in transition dairy cows Asian-Australasian Journal of Animal Sciences 19 (3): 390-395

KEYWORDS: Chinese Holstein dairy cows; rumen-protected choline; milk performance; blood metabolic parameters; antioxidant vitamins; dietary; liver; supplementation; postpartum; protein; period; yield

SUMMARY: This work was conducted to study the effect of rumen-protected choline (RPC) addition oil milk performance and blood metabolic parameters in transition dairy cows. In Experiment 1, fourteen Chinese Holstein dairy cows were Supplemented with 0 or 20 g/d of RPC from 7 d before expected calving to 21 d post partum. Feeding of RPC tended to increase milk yield and milk protein percentage. while milk fat and lactose percentage were not changed, Plasma concentrations of glucose tended to increase as cows consumed RPC. while plasma concentrations of triglycerides. very low density lipoproteins. cholesterol and nonesterified fatty acids were not significantly different between the two groups, In Experiment 2, thirty-six Chinese Holstein dairy cows were supplemented with 0, 30, 60 or 90 g/d RPC from 15 d before expected calving to 15 d post partum. Feeding of RPC tended to increase yield of milk and 4% fat-corrected milk for all the lactating cows, and milk composition was similar among the four groups, Plasma concentratiom of glucose were remained at a higher level in 30 or 60 g/d RPC-supplemented groups, and nonesterified fatty acids v ere decreased ill the 30 g/d group. Concentrations of triglycerides tended to reduce in 30 and 90 g/d RPC-supplemented animals. and cholesterol was reduced in 0 or 30 g/d group. These results suggest that RPC addition tended to increase milk field and improve blood metabolic parameters during transition dairy Cows, and feeding 30 g/d of RPC may be the optimal.
(10-March-2006)
 

Paul SS, Kamra DN, Sastry VRB, Sahu NP (2006) Effect of adding an anaerobic fungal culture isolated from a wild blue bull (Boselophus tragocamelus) to rumen fluid from buffaloes on in vitro fibrolytic enzyme activity, fermentation and degradation of tannins and tannin-containing Kachnar tree (Bauhinia variegata) leaves and wheat straw Journal Of The Science Of Food And Agriculture 86 (2): 258-270

KEYWORDS: anaerobic fungus; buffalo; blue bull; digestibility; Boselophus tragocamelus; tannin; fibre digestion; invivo ruminal fermentation; volatile fatty-acids; sp-nov; gen-nov; digestion; bacteria; goats; invitro; fiber; sheep

SUMMARY: The study investigated the effects of adding an anaerobic fungus (Piromyces sp FNG5; isolated from the faeces of a wild blue bull) to the rumen fluid of buffaloes consuming a basal diet of wheat straw and concentrates on in vitro enzyme activities, fermentation and degradation of tannins and tannin-rich tree leaves and wheat straw. In experiment 1, strained rumen fluid was incubated for 24 and 48h, in quadruplicate, with or without fungal culture using condensed tannin-rich Bauhinia variegata leaves as substrates. In experiment 2, in vitro incubation medium containing wheat straw and different concentrations of added tannic acid (0 - 1.2 mg mL(-1)) were incubated for 48 h, in quadruplicate, with strained buffalo rumen fluid with or without fungal culture. In experiment 3, tolerance of the fungal isolate to tannic acid was tested by estimating fungal growth in pure culture medium containing different concentrations (0-50 g L-1) of tannic acid. In in vitro studies with Bauhinia variegata tree leaves, addition of the fungal isolate to buffalo strained rumen liquor resulted in significant (P < 0.01) increase in neutral detergent fibre (NDF) digestibility and activities of carboxymethyl cellulase (P < 0.05) and xylanase (P < 0.05) at 24h fermentation. There was 12.35% increase (P < 0.01) in condensed tannin (CT) degradation on addition of the fungal isolate at 48 h fermentation. In in vitro studies with wheat straw, addition of the fungus caused an increase in apparent digestibility (P < 0.01), true digestibility (P < 0.05), NDF digestibility (P < 0.05), activities of carboxymethyl cellulase (P < 0.001), beta-glucosidase (P < 0.001), xylanase (P < 0.001), acetyl esterase (P < 0.001) and degradation of tannic acid (P < 0.05). Rumen liquor from buffaloes which had never been exposed to tannin-containing diet had been found to have substantial inherent tannic acid-degrading ability (degraded 55.3% of added tannic acid within 24 h of fermentation). The fungus could tolerate tannic acid concentration up to 20 g L-1 in growth medium. The results of this study suggest that introduction of an anaerobic fungal isolate with superior lignocellulolytic activity isolated from the faeces of a wild herbivore may improve fibre digestion from tannin-containing feeds and degradation of tannins in the rumen of buffaloes.
(10-March-2006)
 

Pottier J, Focant M, Debier C, De Buysser G, Goffe C, Mignolet E, Froidmont E, Larondelle Y (2006) Effect of dietary vitamin E on rumen biohydrogenation pathways and milk fat depression in dairy cows fed high-fat diets Journal of Dairy Science 89 (2): 685-692

KEYWORDS: biohydrogenation; milk fat depression; oilseed; vitamin E; conjugated linoleic-acid; endogenous electron-donor; alpha-tocopherolquinol; megasphaera-elsdenii; E supplementation; identification; profiles; bacteria; trans-10; isomers

SUMMARY: Six lactating Holstein cows were assigned to a replicated Latin square design to test the effect of dietary vitamin E on milk fat depression and on the increased production of milk trans-10 C18:1 classically observed when feeding high doses of unsaturated fatty acids with low-fiber diets. Two diets (linseed diet and linseed diet + 12,000 IU of vitamin E/d) were compared during 2 periods of 21 d. The linseed diet presented a forage-to-concentrate ratio of 50: 50 and contained extruded linseed (1.86 kg/d) and linseed oil (190 g/d). It was conceived to favor the "trans-11 to trans-10 shift" ( low structural value and high level of unsaturated fatty acids). Milk yield and protein content were not affected by the diets. Milk of cows fed the linseed diet presented the typical symptoms of milk fat depression associated with a shift in biohydrogenation pathways: low fat content and high level of trans-10 C18:1. However, the high dose of dietary vitamin E provided significantly increased milk fat content (by 17.93%) and yield (by 15.56%) and decreased trans-10 C18:1 content (by 47.06%). In addition, it managed to significantly increase the daily yields of vaccenic (by 102.56%) and rumenic acids (by 56.67%). However, the sequence of administration of vitamin E influenced its effect, as vitamin E seemed to be more active in limiting the "trans-11 to trans-10 shift" when it was incorporated in the diet simultaneously with the fat. Once the shift had occurred, the subsequent addition of vitamin E was no longer able to completely counteract this process.
(10-March-2006)
 

Shingfield KJ, Reynolds CK, Hervas G, Griinari JM, Grandison AS, Beever DE (2006) Examination of the persistency of milk fatty acid composition responses to fish oil and sunflower oil in the diet of dairy cows Journal of Dairy Science 89 (2): 714-732

KEYWORDS: trans fatty acids; conjugated linoleic acids; polyenoic fatty acid; conjugated linoleic-acid; trans-octadecenoic acids; forage-concentrate ratio; bovine-milk; extruded soybeans; duodenal flow; linseed oil; oleic-acid; in-vitro; microbial biohydrogenation

SUMMARY: Based on the potential benefits of cis-9, trans-11 conjugated linoleic acid (CLA) for human health, there is a need to develop effective strategies for enhancing milk fat CLA concentrations. Levels of cis-9, trans-11 CLA in milk can be increased by supplements of fish oil (FO) and sunflower oil (SO), but there is considerable variation in the response. Part of this variance may reflect time-dependent ruminal adaptations to high levels of lipid in the diet, which lead to alterations in the formation of specific biohydrogenation intermediates. To test this hypothesis, 16 late lactation Holstein-British Friesian cows were used in a repeated measures randomized block design to examine milk fatty acid composition responses to FO and SO in the diet over a 28-d period. Cows were allocated at random to corn silage-based rations (8 per treatment) containing 0 (control) or 45 g of oil supplement/ kg of dry matter consisting (1:2; wt/wt) of FO and SO (FSO), and milk composition was determined on alternate days from d 1. Compared with the control, the FSO diet decreased mean dry matter intake (21.1 vs. 17.9 kg/d), milk fat (47.7 vs. 32.6 g/kg), and protein content (36.1 vs. 33.3 g/kg), but had no effect on milk yield (27.1 vs. 26.4 kg/d). Reductions in milk fat content relative to the FSO diet were associated with increases in milk trans-10 18: 1, trans-10, cis-12 CLA, and trans-9, cis-11 CLA concentrations (r(2) = 0.74, 0.57, and 0.80, respectively). Compared with the control, the FSO diet reduced milk 4: 0 to 18: 0 and cis 18:1 content and increased trans 18:1, trans 18:2, cis-9, trans-11 CLA, 20: 5 n-3, and 22: 6 n-3 concentrations. The FSO diet caused a rapid elevation in milk cis-9, trans-11 CLA content, reaching a maximum of 5.37 g/100 g of fatty acids on d 5, but these increases were transient, declining to 2.35 g/100 g of fatty acids by d 15. They remained relatively constant thereafter. Even though concentrations of trans-11 18: 1 followed the same pattern of temporal changes as cis-9, trans-11 CLA, the total trans 18:1 content of FSO milk was unchanged because of the concomitant increases in the concentration of other isomers (Delta(4-10) and Delta(12-15)), predominantely trans-10 18:1. In conclusion, supplementing diets with FSO enhances milk fat cis-9, trans-11 CLA content, but the high level of enrichment declines because of changes in ruminal biohydrogenation that result in trans-10 replacing trans-11 as the major 18:1 biohydrogenation intermediate formed in the rumen.
(10-March-2006)
 

Busquet M, Calsamiglia S, Ferret A, Kamel C (2006) Plant extracts affect in vitro rumen microbial fermentation Journal Of Dairy Science 89 (2): 761-771

KEYWORDS: plant extract; rumen fermentation; yucca-schidigera; essential oils; antimicrobial properties; ruminal microorganisms; continuous-culture; potential impact; saponins; inhibition; components; bacteria

SUMMARY: Different doses of 12 plant extracts and 6 secondary plant metabolites were incubated for 24 h in diluted ruminal fluid with a 50: 50 forage: concentrate diet. Treatments were: control (no additive), plant extracts (anise oil, cade oil, capsicum oil, cinnamon oil, clove bud oil, dill oil, fenugreek, garlic oil, ginger oil, oregano oil, tea tree oil, and yucca), and secondary plant metabolites (anethol, benzyl salicylate, carvacrol, carvone, cinnamaldehyde, and eugenol). Each treatment was supplied at 3, 30, 300, and 3,000 mg/L of culture fluid. At 3,000 mg/L, most treatments decreased total volatile fatty acid concentration, but cade oil, capsicum oil, dill oil, fenugreek, ginger oil, and yucca had no effect. Different doses of anethol, anise oil, carvone, and tea tree oil decreased the proportion of acetate and propionate, which suggests that these compounds may not be nutritionally beneficial to dairy cattle. Garlic oil (300 and 3,000 mg/L) and benzyl salicylate (300 and 3,000 mg/L) reduced acetate and increased propionate and butyrate proportions, suggesting that methane production was inhibited. At 3,000 mg/L, capsicum oil, carvacrol, carvone, cinnamaldehyde, cinnamon oil, clove bud oil, eugenol, fenugreek, and oregano oil resulted in a 30 to 50% reduction in ammonia N concentration. Careful selection and combination of these extracts may allow the manipulation of rumen microbial fermentation.
(10-March-2006)
 

Masoero F, Pulimeno AM, Rossi F (2005) Effect of extrusion, espansion and toasting on the nutritional value of peas, faba beans and Lupins Italian Journal of Animal Science 4 (2): 177-189

KEYWORDS: legumes; nutritional value; technological treatments; digestibility; l. seed proteins; broken peas; albus l.; rumen; digestibility; degradability; degradation; feedstuffs; cooking; invitro

SUMMARY: An assessment was made of the effect that different treatments (toasting, expansion, extrusion) have on the nutritional value of protein plants (pea, faba bean, lupin). In a randomized block design, feeds were screened for enzymatic digestibility of starch and protein, N solubility and in vitro protein degradability. Expansion and extrusion cause increased starch enzymatic degradability while toasting produced virtually no effects. In peas this value increased from 11.80% in meal to 39.70% in the extruded product; 85.37% is the percentage for the expanded product, while 10.90% is the starch digestibility value for toasted peas. In faba beans the extrusion process increased starch digestibility from 11.39% to 85.05%, while in extruded lupins a complete starch hydrolysis was obtained, while in the meal the polysaccharide digestion was 54.48%.
The expansion and extrusion processes significantly decreased rumen degradability during the first 8 hours of incubation. Toasted peas had lower degradability if compared with controls but not with the other treatments. The only potentially alternative source to soybean is the extruded faba bean. In spite of its lower protein content, this feed is characterized by a considerably lower in vitro protein degradability than soybean. This implies that the digestible food protein content is comparable (124.90 g/kg DM) to that of soybean (109.78 g/kg DM) and definitely higher than that of all other protein plants.
(10-March-2006)
 

Kis G, Grbesa D, Kostelic A, Karolyi D (2005) Estimating grass and grass silage degradation characteristics by in situ and in vitro gas production methods Italian Journal of Animal Science 4: 142-144 Suppl. 3

KEYWORDS: grass; in situ; gas production; maturity; rumen fluid; digestibility; fermentation; kinetics; feeds; bag

SUMMARY: Fermentation characteristics of grass and grass silage at different maturities were studied using in situ and in vitro gas production methods. In situ data determined difference between grass and silage. Degradable fraction decreased as grass matured while the undegradable fraction increased. Rate of degradation (kd) was slower for silage than fresh grass. Gas production method (GP) data showed that fermentation of degradable fraction was different between stage of maturity in both grass and silage. Other data did not show any difference with the exception for the rate of GP of soluble and undegradable fraction. The in situ degradation characteristics were estimated from GP characteristics. The degradable and undegradable fractions could be estimated by multiple relationships. Using the three-phases model for gas production kd and fermentable organic matter could be estimated from the same parameters. The only in situ parameter that could not be estimated with GP parameters was the soluble fraction. The GP method and the three phases model provided to be an alternative to the in situ method for animal feed evaluations.
(10-March-2006)
 

Williams YJ, Wales WJ, Doyle PT, Egan AR, Stockdale CR (2005) Effects of grain or hay supplementation on the chewing behaviour and stability of rumen fermentation of dairy cows grazing perennial ryegrass-based pasture in spring Australian Journal of Experimental Agriculture 45 (12): 1519-1528

KEYWORDS: ammonia; grazing behaviour; pH; supplementary feeding; volatile fatty acids; milk-production responses; dry-matter; protein degradability; continuous-culture; diurnal-variation; ruminal ph; fluid ph; digestion; concentrate; fiber

SUMMARY: Cows grazing highly digestible pasture in early spring can have very low rumen fluid pH that can negatively impact on the efficiency of microbial digestion. In this experiment, cows in early lactation grazed perennial ryegrass ( Lolium perenne L.)-based pasture alone at low or high allowances, or at a low allowance supplemented with either a cereal grain pellet, a chopped hay cube or a cube containing cereal grain and chopped hay to determine the effects of the addition of neutral detergent fibre as hay on chewing behaviour and stability of rumen fermentation. The hypotheses tested were that: (i) supplementing high digestibility ryegrass pasture with pelleted cereal grain would increase the proportion of the day that the pH of rumen fluid was below 6.0 and would decrease the rate of degradation of neutral detergent fibre in pasture and hay; and (ii) the inclusion of chopped hay with the cereal grain supplement in cubes would reduce the proportion of the day that the rumen fluid pH was below 6.0 and restore the rate of degradation of neutral detergent fibre in pasture and hay to that in unsupplemented cows.
Rumen fluid pH was highest (P< 0.05) in cows fed a chopped hay cube and lowest ( P< 0.05) in cows fed a cube containing cereal grain and chopped hay, with no significant (P> 0.05) difference between those fed pasture only or cereal grain pellets. The introduction of grain, with or without hay, did not substantially alter the pattern or magnitude of changes in rumen fluid pH, but did reduce ( P< 0.05) the rate of degradation of neutral detergent fibre in pasture (5.3 v. 7.6%/ h) and hay (2.7 v. 5.0%/h) in the rumen. Rumen degradation rates of pasture dry matter and neutral detergent fibre were not improved by adding chopped hay. Total volatile fatty acid concentrations in rumen fluid were highest ( P< 0.05) on the high pasture allowance treatment and lowest ( P< 0.05) on the low pasture allowance and the chopped hay cube treatments. Supplementation with grain reduced ( P< 0.05) the proportion of acetate and increased ( P< 0.05) the proportion of propionate in total volatile fatty acids. There were no significant ( P> 0.05) effects of dietary treatment on time spent grazing or on rate of biting while grazing. Cows in treatments receiving grain supplements ( 532 min) and those in the high pasture allowance treatment ( 566 min) spent more ( P< 0.05) time ruminating than those in the low pasture allowance ( 415 min) and chopped hay cube ( 465 min) treatments. The relative contributions of low pH and of starch to the reduction in rates of dry matter and neutral detergent fibre degradation in the rumen cannot be determined from this experiment, however, it is likely that both factors contribute to a relative increase in the metabolic activity of non-cellulolytic microorganisms.
(10-March-2006)
 

Detmann E, Paulino MF, Valadares SD, Cecon PR, Zervoudakis JT, Cabral LD, Goncalves LC, Valadares RFD (2005) Effects of feeding different protein levels of supplements to finishing cattle in pasture during the dry to rainy transition season on apparent digestibility and metabolism of ruminal and nitrogenous compounds. Revista Brasileira De Zootecnia-Brazilian Journal Of Animal Science 34 (4): 1380-1391

KEYWORDS: nitrogenous compounds; partial digestibility; rumen ammonia nitrogen; rumen pH; signalgrass; fiber digestion; steers; rumen; starch; parameters; energy; spectrophotometry; bacterial; alfalfa; forages

SUMMARY: The objective of this trial was to evaluate ruminal, intestinal, and total tract apparent digestibilities of nutrients as well as metabolism of ruminal and nitrogenous compounds in supplemented finishing cattle during the drought to rainy transition season. Five Holstein x Zebu steers averaging 304 kg of live weight and 24 months of age located in five paddocks (0.34 ha each) of Brachiaria decumbens were used in this trial. The supplements fed (4 kg/animal/day) contained ground corn, whole soybean, urea, ammonium sulfate, and minerals and were formulated to yield, on as fed basis, 12, 16, 20, and 24% of crude protein (CP). Four animals were assigned to a 4 x 4 Latin square with experimental periods lasting 21 days. The remaining animal was not supplemented and was used for comparative purposes (CONT). No significant differences in ruminal, intestinal, and total tract apparent digestibilities of dry matter, organic matter, and neutral detergent fiber were observed by increasing the CP contents of the supplements. Similarly, abomasal flows of total nitrogen, ammonia nitrogen, and microbial nitrogen (MICN) did not differ when the CP contents of the supplements were increased. However, concentration of ruminal ammonia nitrogen increased linearly by incrementing the CP content of the supplement from 12 to 24%. Microbial efficiency averaged 17.5 g of MICN/kg of organic matter fermented in the rumen (OMFR) across supplements and was higher than that of the CONT (10.6 g of MICN/kg of OMFR). In addition, it was observed a significant Cubic effect for urinary excretion of urea by increasing the CP contents of the supplements.
(25-Jan-2006)
 

Valinote AC, Nogueira JCM, Leme PR, Silva SDE, Cunha JA (2005) Effects of feeding monensin and different sources of fat on the ruminal population of ciliate protozoa in Nellore steers. Revista Brasileira De Zootecnia-Brazilian Journal Of Animal Science 34 (4): 1418-1423

KEYWORDS: calcium salt of fatty acid; cattle; cottonseed; ionophores; protozoology; conjugated linoleic-acid; rumen fermentation; supplemental fat; sheep; oil; metabolism; digestion; diets; biohydrogenation; protein

SUMMARY: Four ruminally and duodenally cannulated Nellore steers were assigned to a 4 x 4 latin square to study the effects of feeding monensin (M) and different sources of fat on the ruminal population of ciliate protozoa and ruminal pH. The experimental diets contained (DM basis) 19% of sugar cane and were supplemented with M [control (CTRL)], M plus calcium salts of fatty acids (CSFA), M plus whole cottonseed (MWCS), or only WCS. Ruminal contents were sampled at 0, 2, 4, 6, and 8 hours post-feeding. In order to identify the ciliate protozoa a Sedgwick-Rafter count cell and an optic microscope with slide area of 0.4362 mm(2) were used. No significant differences in ruminal pH were observed among diets. Both cottonseed treatments (MWCS and WCS) reduced the ruminal population of the ciliate protozoa investigated, mainly the Entodinium, possibly because of the slow release of fat. Ruminal counts of Diplodinium, Epidinium, Eudiplodinium, and total protozoa were all affected by time post-feeding. Calcium salts of fatty acids seemed to be inert in the ruminal environment because no significant changes were observed in the protozoa counts. Moreover, feeding CRTL and MWCS diets to Nellore steers did not change the ruminal population of ciliate protozoa in this trial.
(25-Jan-2006)
 

Gierus A, de Jonge L, Meijer GAL (2005) Physico-chemical characteristics and degradation rate of soluble protein obtained from the washout fraction of feeds. Livestock Production Science 97 (2-3): 219-229

KEYWORDS: nylon bag; washout fraction; trichloroacetic acid; soluble protein degradation; ruminal degradation; dairy-cows; in-situ; grass-silage; rumen; degradability; hay; digestibility; supplements; system

SUMMARY: The (water)-soluble fraction of feeds is often assumed to be completely and immediately degraded in the rumen. The objective of this study was to separate the washout fraction (fraction A) obtained usually by difference after submitting the nylon bags to the machine-washing program, to investigate the nature and the degradation of the soluble crude protein in the washout fraction. The washout fraction obtained in vitro (filtrate) of 10 feeds was collected in water using nylon mesh as a filter. The feeds used in the study were: two grass silages, soybean meal, three corn gluten feeds, lupine meal, rapeseed meal, wet brewers grain silage and corn gluten feed silage. Average N losses during filtration and from machine-washed nylon bags ranged from 15% (rape seed meal) to 74% (grass silage) and were not different between procedures. N recovered in the filtrate ranged from 12% (soybean meal) to 60% (corn gluten feed silage) of sample N. The three fractions obtained from the filtrate were: soluble protein (TP), non-protein N (NPN) and fine particles (NS). The NS fraction was obtained after centrifugation of the filtrate and comprised 0% to 87% of N in the filtrate. Soluble protein (TP) in the supernatant was obtained after precipitation with trichloroacetic acid and N in the remaining supernatant was defined as non-protein N (NPN). Significant amounts of TP were found in soybean meal (58%), lupine meal (30%) and rapeseed meal (27%) as percent of total N in the filtrate. NPN ranged from 13% to 100% of N in the filtrate. The in vitro incubation of the protein N (NS +TP) showed that all fractions were not completely degraded, suggesting a potential participation as escape protein. Fine particles in the filtrate have similar degradation rates as the residue left in the filter. It is concluded that the washout fraction consisted of different crude protein fractions that were not always completely and immediately degraded in the rumen.
(25-Jan-2006)
 

Ramirez-Perez AH, Meschy F (2005) Phosphorus requirements by ruminal microorganisms: A review Interciencia 30 (11): 664-673 (Spanish)

KEYWORDS: semicontinuous culture system; dry-matter intake; dairy-cows; reproductive-performance; p-32-labeled phosphate; phytate phosphorus; lactating goats; milk-production; rumen microbes; heat-treatment

SUMMARY: The effect of phosphorus (P) on microbial activity and the use of nutrients by the ruminant are described. Recent recommendations on mineral feeding reduce dietary P concentration. Phosphorus supply must satisfy the requirements of ruminal microbes in order to ensure an adequate fermentation process. Microbial P requirements arc, greater for cellulose breakdown than for protein synthesis (6.9 vs 4.3g available P/kg of fermentable organic matter in the rumen). Phosphorus utilization by bacteria depends on its dietary content, availability, and endogenous contribution through saliva, as well as on the microbial response to P variations in the ruminal content. Due to these complexities, further investigation is needed. Furthermore, any decrease in excreted P because of a reduction in its intake will have a positive effect on the environment.
(25-Jan-2006)
 

Mihalikova K, Gresakova L, Boldizarova K, Faix S, Leng L, Kisidayova S (2005) The effects of organic selenium supplementation on the rumen ciliate population in sheep. Folia Microbiologica 50 (4): 353-356

KEYWORDS: in-vitro fermentation; oxidative stress; meadow hay; vitamin-e; metabolism; selenomethionine; cellulose; toxicity; protozoa; protein

SUMMARY: The effect of selenium supplementation on the rumen protozoan population of sheep was demonstrated. Both the total and generic counts of rumen ciliates in sheep fed a diet with basal Se content (70 mu g/kg dry matter) were compared to those of animals given feed supplemented with inorganic (disodium selenite) or organic Se (selenized yeast) (310 mu g/kg dry matter). The genera of Entodinium, Isotricha, Dasytricha, Ophryoscolex, Diploplastron and Polyplastron occurred in all sheep except for the control, in which Ophryoscolex was not observed. The population of Ophryoscolex caudatus f. tricoronatus was significantly higher in sheep supplemented with organic Se than in animals given inorganic Se (by 160 %). Supplementation of feed with selenized yeast induced significant growth in the Diploplastron population (by 63 %) while no change occurred in sheep given selenite. The populations of Dasytricha ruminantium and Polyplastron multivesiculatum were higher than control in both Se-supplemented groups. The ciliate population of Entodinium spp. was not influenced by Se supplements. Our results suggest a protective effect of Se feed supplementation on the development of some rumen ciliate species in young ruminants.
(25-Jan-2006)
 

Fike JH, Saker KE, O'Keefe SF, Marriott NG, Ward DL, Fontenot JP, Veit HP
(2005) Effects of Tasco (a seaweed extract) and heat stress on N metabolism and meat fatty acids in wether lambs fed hays containing endophyte-infected fescue. Small Ruminant Research 60 (3): 237-245

KEYWORDS: Ascophyllum nodosum; nitrogen; digestibility; VFA; fatty acids; sheep; feedlot-finished steers; immune cell response; tall fescue; ambient-temperature; antioxidant status; forage; performance; ruminants; drought; ammonia

SUMMARY: Wether lambs (n=27, average BW=40kg) were used to test response to forage treated with Tasco-Forage (an extract of the brown kelp Ascophyllum nodosum) prior to conserving, or to direct feeding of the extract (Tasco-EX). Hays made from endophyte (Neoyphodium coenophialum)-infested tall fescue (Festuca arundinacea)-based pasture received 0 or 3 kg of Tasco/ha prior to harvest. Lambs, blocked by weight, were randomly allotted to three diets: (1) control hay, (2) treated hay, and (3)#1 + Tasco-EX fed at 1% of the diet. Hays were low in CP (< 7%) so all lambs were fed soybean meal (12% of the diet) in addition to trace mineralized salt. Diets were fed at 1.5% BW to prevent refusals. Total collections (7 d) were made during periods without or with applied heat stress. After each period, rumen contents were obtained to determine pH, NH3 and VFA. Lambs were sacrificed post-trial. A subset was used to evaluate sensory traits and muscle fatty acids. Lambs were in negative N balance during the study and Tasco treatments did not affect N metabolism. Fecal N tended (P < 0.10) to increase with short duration heat stress Causing a concomitant decrease (P < 0.05) in apparent N digestibility (58.6 versus 56.1%; S.E. = 0.7). Urinary N loss decreased (P < 0.001) with heat stress (8.0 versus 5.9 g/d; S.E. = 0.2), resulting in increased (P < 0.001) N retention (-2.1 versus -0.3 g/d; S.E. = 0.2). Apparent OM digestibility was not affected by beat stress but was greater (P < 0.05) for lambs fed Tasco-EX treatment than those fed treated hay. Treatment diets decreased (P < 0.05) ruminal butyrate. Heat stress increased (P < 0.05) acetate and total VFA and decreased (P < 0.01) ruiminal pH. A tendency (P < 0.11) of increased 14:1 omega 5, decreased (P < 0.05) 18:0 and total saturated fatty acids in muscle was observed with Tasco diets. Meat sensory characteristics were not affected by treatment. Tasco may alter some aspects of rumen or lipid metabolism but has no effect on N metabolism or meat sensory characteristics of sheep fed restricted, low-quality diets.
(25-Jan-2006)
 

Bhatta R, Vaithiyanathan S, Singh NP, Shinde AK, Verma DL (2005) Effect of feeding tree leaves as supplements on the nutrient digestion and rumen fermentation pattern in sheep grazing on semi-arid range of India – I. Small Ruminant Research 60 (3): 273-280

KEYWORDS: rangeland; tree leaves; supplementation; rumen fermentation; sheep; condensed tannins; polyethylene-glycol; prosopis-cineraria; lotus-pedunculatus; ceratonia-siliqua; nutritional-value; seed husk; growth; goats; digestibility

SUMMARY: A study was carried out to determine the effect of feeding different tree leaves as Supplements on nutrient digestion, rumen fermentation and blood parameters of sheep grazing oil a semi-arid rangeland. Thirty adult Malpura rains of uniform body weight (39.0 +/- 0.75) were divided into five groups of six each. They were grazed as a single flock from 08.00 to 17.00 h on a semi-arid rangeland. After the end of the grazing period, the first group (G 1), which was not provided with supplementation, served as the control. The second group (G2) was Supplemented with 200 g of a concentrate mixture per head per day, whereas the third, fourth and fifth groups (G3-G5) were provided with approximately 200 g DM d(-1) of freshly cut foliage from Prosopis cineraria, Acacia nilotica and Albezia lebbek. The foliage from P cineraria contained 133.4 g kg(-1) DM condensed tannin (CT) with protein precipitating capacity (PPC) of 66 g kg(-1) DM, whereas A. nilotica contained 18.9 g kg(-1) DM hydrolysable tannin (HT) with PPC of 11.5 g kg(-1) DM. However, A. lebbek did not contain any tannin. The protein contents were 119, 139 and 194 g kg-1 DM, respectively. The DMI (g d(-1)) was 688, 916, 1024, 1003, 999 in G1, G2, G3, G4 and G5, respectively. Digestible crude protein (DCP) and metabolizable energy (ME) intakes in Supplemented groups G2-G5 were higher (P < 0.05) than in the control (G 1). Supplementation improved the DM digestibility in all groups, whereas CP digestibility was lower (P < 0.05) in G3 compared to G2, G4 and G5. Rumen fermentation study conducted 6 h after Supplementation revealed that total N, ammonia N, and total VFA levels were lower (P < 0.05) in G3 compared to the other Supplemented groups. Although the haemoglobin (Hb) levels were similar among groups, blood urea N (BUN) was lowest in G3 compared to the other groups. The initial body weights were similar among groups (mean 39 kg). After 60 days of experimental feeding, all groups maintained their body weight, except the control group (GI), which lost body weight. It was observed, that Supplementation with tree leaves containing CT like P cineraria helps in better rumen fermentation pattern by preventing excessive loss of nitrogen. It was concluded that maximum nutritional benefits of tree leaves could be harvested, if used as supplement rather than as a sole feed.
(25-Jan-2006)
 

Bhatta R, Vaithiyanathan S, Singh NP, Shinde AK, Verma DL (2005) Effect of tree leaf as supplementation on nutrient digestion and rumen fermentation pattern in sheep grazing semi-arid range of India – II. Small Ruminant Research 60 (3): 281-288

KEYWORDS: rangeland; tree leaves; sheep; rumen fermentation; tannin; condensed tannins; prosopis-cineraria; polyethylene-glycol; lotus-pedunculatus; nutritional-value; seasonal-changes; seed husk; ruminants; growth; leaves

SUMMARY: A study was conducted to evaluate the effects of supplementing with different tree leaves on nutrient digestion, Runen fermentation and blood parameters of sheep. Thirty adult Malpura rains (39.0 +/- 0.56 kg) were divided into five groups of six each. They were grazed as a single flock oil a semi-arid rangeland and after the end of routine grazing period (08:00-17:00 h), first group (G 1), which was not provided with any supplementation, served as control group. Second group (G2) was supplemented with 200 g of a conventional concentrate mixture per head per day, whereas third, fourth and fifth groups (G3, G4and G5) were Supplemented with approximately 200 g dry matter (DM) per day freshly cut foliage from Ailanthes excelsa, Azardirachta indica and Bauhinia racemosa, respectively. Protein content (g kg(-1) DM) in A. excelsa, A. indica and B. racemosa foliage was 197, 128 and 132, respectively. A. indica and B. racemosa foliages also contained 123.2 and 211.2 g kg(-1) DM condensed tannin (CT) with protein precipitating capacity (PPC) of 16.5 and 46.5 g kg(-1) DM. None of the tree leaves contained hydrolysable tannin (HT). Dry matter intake (DMI, a day(-1)) was 591, 766, 865,974 and 939 in G1, G2, G3, G4 and G5, respectively. Digestiblecrude protein (DCP) and metabolisable energy (ME) intakes in supplemented groups G2-G5 were higher (P < 0.05) compared to control (G1). Supplementation improved digestibility of all nutrients in all groups. Rumen fermentation study indicated lower (P < 0.05) ammonia and total N in the rumen liquor collected from G5 sheep compared to the other supplemented groups. Although haemoglobin (Hb, g dl(-1)) levels showed small changes among groups, blood urea nitrogen (BUN, mg dl(-1)) was lowest in G5 compared to the other groups. Initial BW were similar among the groups. After 60 days of experimental feeding, all animals maintained their BW, except sheep in the control group (G1), which lost BW. Results indicate that for adult sheep grazing on a semi-arid range, supplementation with a concentrate mixture could be replaced by tree leaves like A. excelsa, A. indica and B. racemosa, during the lean season to maintain their BW. In addition, supplementing with tree leaves containing condensed tannin has advantages in terms of N utilization.
(25-Jan-2006)
 

Reddy MSS, Chen F, Shadle G, Jackson L, Aljoe H, Dixon RA (2005) Targeted down-regulation of cytochrome P450 enzymes for forage quality improvement in alfalfa (Medicago sativa L.) Proceedings of the National Academy of Sciences of the United States of America 102 (46): 16573-16578

KEYWORDS: forage digestibility; lignin modification; metabolic engineering; cell-wall composition; cinnamyl alcohol-dehydrogenase; lignin biosynthesis; phenylpropanoid metabolism; invitro digestibility; arabidopsis-thaliana; transgenic alfalfa; ferulic acid; gene encodes; dry-matter

SUMMARY: Improving the digestibility of forages provides a means to enhance animal performance and protect the environment against excessive animal waste. Increased lignin content during maturity, and corresponding changes in lignin composition, correlate with decreased digestibility of forages. These relationships have yet to be investigated in isogenic systems. By targeting three specific cytochrome P450 enzymes of the lignin pathway for antisense downregulation, we generated transgenic alfalfa lines with a range of differences in lignin content and composition. There was a strong negative relationship between lignin content and rumen digestibility, but no relationship between lignin composition and digestibility, in these transgenic lines. Models for genetic manipulation of forage digestibility based on the changes in lignin composition that increase paper-pulping efficiency in trees are therefore invalid. Down-regulation of 4-coumarate 3-hydroxylase provided the largest improvements in digestibility yet seen in a forage crop.
(25-Jan-2006)
 

Smith AH, Zoetendal E, Mackie RI (2005) Bacterial mechanisms to overcome inhibitory effects of dietary tannins Microbial Ecology 50 (2): 197-205

KEYWORDS: c-14-labeled condensed tannins; east-african ruminants; mulga acacia-aneura; sp-nov; streptococcus-gallolyticus; lotus-corniculatus; in-vitro; eubacterium-oxidoreducens; antimicrobial properties; gastrointestinal-tract

SUMMARY: High concentrations of tannins in fodder plants inhibit gastrointestinal bacteria and reduce ruminant performance. Increasing the proportion of tannin-resistant bacteria in the rumen protects ruminants from antinutritional effects. The reason for the protective effect is unclear, but could be elucidated if the mechanism(s) by which tannins inhibit bacteria and the mechanisms of tannin resistance were understood. A review of the literature indicates that the ability of tannins to complex with polymers and minerals is the basis of the inhibitory effect on gastrointestinal bacteria. Mechanisms by which bacteria can overcome inhibition include tannin modification/degradation, dissociation of tannin-substrate complexes, tannin inactivation by high-affinity binders, and membrane modification/repair and metal ion sequestration. Understanding the mechanism of action of tannins and the mechanism(s) bacteria use to overcome the inhibitory effects will allow better management of the rumen ecosystem to reduce the antinutritional effects of tannin-rich fodder plants and thereby improve ruminant production.
(25-Jan-2006)
 

Lourenco M, Vlaeminck B, Bruinenberg M, Demeyer D, Fievez V (2005) Milk fatty acid composition and associated rumen lipolysis and fatty acid hydrogenation when feeding forages from intensively managed or semi-natural grasslands. Animal Research 54 (6): 471-484

KEYWORDS: grasslands; hydrogenation; rumen; milk fatty acids; CLA; conjugated linoleic-acid; lactating dairy-cows; blue young bulls; legume silages; in-vitro; fish-oil; biohydrogenation; trans; digestion; lambs

SUMMARY: In order to evaluate the effect of replacing intensive forage by semi- natural grassland products on rumen lipid metabolism and milk fatty acid composition, four lactating and rumen canulated Holstein cows were used in a 4 x 4 Latin square design. Four different diets were fed: diet 100 IM - 100% intensively managed silage ( IM), diet 20 SPP - 80% IM plus 20% semi- natural but species poor silage ( SPP), diet 60 SPP - 40% IM plus 60% SPP and diet 60 SPR - 40% IM plus 60% semi- natural species rich silage ( SPR). The silages showed significant differences in total fat content and in proportions of C18: 2 n- 6 and C18: 3 n- 3. Despite the reduced dietary supply of C18: 3 n- 3 with diets 60 SPP and 60 SPR, differences in milk C18: 3 n- 3 were small, suggesting higher recoveries of C18: 3 n- 3. Presumably, the latter are related to a higher transfer efficiency of C18: 3 n- 3 from the duodenum to the mammary gland, since rumen biohydrogenation, estimated from rumen pool size and first order rumen clearance kinetics, were similar among diets. CLA c9t11 in milk from cows fed diet 60 SPR were almost doubled compared to feeding one of the other diets. This has been related to the partial inhibition of rumen biohydrogenation of C18: 3 n- 3 and/ or C18: 2 n- 6, as suggested by the increased proportions of hydrogenation isomers and reduced stearic acid proportions in rumen pool samples. In conclusion, the results suggest that the use of semi- natural grasslands in the diet of the animals reduce to some extent complete rumen biohydrogenation, which leads to an increase in milk CLA.
(25-Jan-2006)
 

Lu CD, Kawas JR, Mahgoub OG (2005) Fibre digestion and utilization in goats. Small Ruminant Research 60 (1-2): 45-52

KEYWORDS: goats; fibre digestion; growth; milk; fed alfalfa hay; milk-production; dairy goats; feed-intake; metabolizable energy; ruminal fermentation; dietary carbohydrate; chewing activities; voluntary intake; detergent fiber

SUMMARY: Dietary fibre contributes significantly to the balancing of nutrient requirements in goats. Dietary fibre also plays a pivotal role in goat production through its influence in and interaction with the intake and digestion of nutrients. Physiological regulation (feedback from metabolic factors) of intake is dominant in goats fed high concentrate diets, while physical fill is the predominant factor in the regulation of intake when goats were fed high-forage diets. Mediated through salivation and buffering capacity, dietary fibre intake influences mastication and rumen fermentation. In growing goats, dietary metabolizable energy density above 2.78 Mcal/kg depresses intake and reduces growth rate in goats. Adequate dietary fibre is essential in producing leaner carcasses in growing goats. In high producing lactating dairy goats, dietary fibre intake plays a role in the prevention of milk fat depression. The effect is mediated through the maintenance of favorable acetate to propionate ratio in the rumen liquor, as acetate is the major precursor of milk fat. It appears that 18-20% ADF or 41 % NDF is nutritionally adequate for high producing lactating dairy goats. For growing goats between 4 and 8 months of age, 23% ADF is recommended. Relationship between chewing time and dietary fibre can be defined by the equation: total chewing time (min/day) = 33.11 + 30.13 ADF intake (%). Milk fat yield can be predicted from dietary fibre intake: milk fat yield (g/day) = 115.78 - 0.128 x ADF intake (g/day) + 0.00021 x (ADF intake, g/day)(2).
(25-Jan-2006)
 

AbuGhazaleh AA, Riley MB, Thies EE, Jenkins TC (2005) Dilution rate and pH effects on the conversion of oleic acid to trans C-18 : 1 positional isomers in continuous culture. Journal of Dairy Science 88 (12): 4334-4341

KEYWORDS: biohydrogenation; oleic acid; pH; dilution rate; unsaturated fatty-acids; lactating dairy-cows; rumen bacteria; milk; biohydrogenation; fermentation; supplementation; fermenters; digestion; protein

SUMMARY: In a previous in vitro study, mixed ruminal microorganisms converted oleic acid to a variety of trans monenes when grown in batch cultures under constant environmental conditions. To determine whether a similar conversion occurs under environmental conditions more typical of the rumen, conversion of C-13-labeled oleic acid to biohydrogenation intermediates was determined in ruminal microorganisms grown in continuous culture at two pH (5.5 and 6.5) and liquid dilution rates (0.05 and 0.10/h) arranged factorially. After each morning feeding of the dual-flow continuous cultures, 250 mg of oleic acid in 5 mL of ethanol were injected into each culture. On d 10, 250 mg of oleic-1-C-13 replaced the unlabelled oleic acid in ethanol. Trans fatty acids were isolated from culture samples by solid phase extraction, and C-13 enrichment and identity of double bond position was determined by gas chromatography-mass spectroscopy. At pH 6.5 and 0.10/h dilution rate, C-13 enrichment was detected in all trans-C-18:1 isomers having double bond positions from C-6 through C-16 in the acyl chain. However, when pH or dilution rate in fermentors was lowered, no C-13 enrichment was detected in any trans isomer with a double bond position beyond C-10. Enrichment in stearic acid increased by reducing culture pH from 6.5 to 5.5, but decreased when dilution rate dropped from 0.10 to 0.05/h. The stearic acid carbons that originated from oleic acid biohydrogenation increased from 30 to 72% when pH dropped from 6.5 to 5.5. The C-13 enrichment of trans-10 was reduced under low pH and dilution rate conditions. The results of this study confirm that ruminal microorganisms are capable of converting oleic acid to a wide variety of trans-C-18:1 positional isomers when ruminal conditions are favorable (such as the pH 6.5 and 0.10/h dilution rate treatment). However, at low pH and dilution rate, the conversion of oleic acid to trans-C-18:1 still occurs, but positional isomers produced are restricted to double bond positions from C-6 to C-10. Low pH conditions also increased the conversion of oleic acid to stearic acid.
(25-Jan-2006)
 

Reveneau C, Ribeiro CVDM, Eastridge ML, St-Pierre NR, Firkins JL (2005) Processing whole cottonseed moderates fatty acid metabolism and improves performance by dairy cows. Journal of Dairy Science 88 (12): 4342-4355

KEYWORDS: pelleted cottonseed; dairy cow; in situ; milk fatty acid; conjugated linoleic-acid; situ ruminal biohydrogenation; milk-fat; linted cottonseed; in-vitro; forage substitute; pima cottonseed; lactating cows; calcium salts; feed-intake

SUMMARY: Pelleting cottonseed (CS) improves handling characteristics. Our objectives were to determine whether increasing the particle size of the CS pellet or dilution of a smaller pellet with delinted CS would limit the rate of CS oil release to optimize digestibility of fatty acids (FA) and fiber while maintaining milk fat production. In a 5 x 5 Latin square design with 3-wk periods, 5 rumen-cannulated cows were fed 1) control with CS hulls (CSH) and CS meal plus tallow and Ca soaps of FA, 2) whole CS (WCS), 3) small CS pellets (SP; 0.44-cm die diameter), 4) larger CS pellets (LP; 0.52-cm die diameter), or 5) a blend of 1/2 SP plus 1/2 partially delinted CS (SPD). Diets contained 39.6% concentrate, 14.4% CS, and 46% forage (40: 60, alfalfa hay: corn silage) on a DM basis and were balanced to have similar concentrations of CS protein, CS fiber, and total fat. In a production trial, dietary treatments were 1) WCS control, 2) LP, 3) SPD, and 4) SPD fed at 90%. Sixty cows averaging 105 d in milk were fed the WCS diet for 2 wk and then assigned to one of the 4 diets for 12 wk. Total tract digestibility of NDF was unaffected, but N digestibility was lower for SPD than for other treatments. Fatty acid digestibility was higher for SP and LP (82.6 and 82.3%) than for CSH or SPD treatments (78.8 and 75.3%), and WCS was intermediate (81.1%). The trans-11C(18:1) from cows fed SP and LP (6.58 and 6.24% of total milk FA) was greater than that from cows fed CSH, WCS, and SPD (3.23, 3.79, and 3.97%). The trans-10C(18:1) in milk fat from SP and LP (0.508 and 0.511%) was higher than that in WCS and SPD diets (0.316 and 0.295%); CSH was intermediate (0.429%). Using passage rates estimated from the NRC, disappearance of total FA in situ was estimated to be 17.7, 44.2, 46.6, and 35.0% for WCS, SP, LP, and SPD, respectively. In the production trial, a diet x week interaction was explained by a trend for progressively greater milk production for SPD and SPD90 than for WCS or LP. Milk fat was lower for LP (2.74%) and SPD90 (2.85%) than for WCS or SPD (3.07 and 3.08%). The fat yield was lower for LP than for SPD (1.09 and 1.30 kg/d); WCS and SPD90 were intermediate (1.23 and 1.21 kg/d). Although having a lower FA digestibility, SPD appeared to minimize negative effects of free oil from SP in the rumen, explaining higher DMI and milk production compared with WCS or LP.
(25-Jan-2006)
 

Busquet M, Calsamiglia S, Ferret A, Carro MD, Kamel C (2005) Effect of garlic oil and four of its compounds on rumen microbial fermentation. Journal of Dairy Science 88 (12): 4393-4404

KEYWORDS: rumen fermentation; garlic oil; diallyl disulfide; allyl mercaptan; antimicrobial properties; ruminal microorganisms; invitro; bacteria; powder; fractionation; biosynthesis; inhibition; cultures; protozoa

SUMMARY: Different concentrations (3, 30, 300, and 3000 mg/L of culture fluid) of garlic oil (GAR), diallyl sulfide (DAS), diallyl disulfide (DAD), allicin (ALL), and allyl mercaptan (ALM) were incubated for 24 h in diluted ruminal fluid with a 50: 50 forage: concentrate diet (17.7% crude protein; 30.7% neutral detergent fiber) to evaluate their effects on rumen microbial fermentation. Garlic oil (30 and 300 mg/L), DAD (30 and 300 mg/L), and ALM (300 mg/L) resulted in lower molar proportion of acetate and higher proportions of propionate and butyrate. In contrast, at 300 mg/L, DAS only increased the proportion of butyrate, and ALL had no effects on volatile fatty acid proportions. In a dual-flow continuous culture of rumen fluid fed the same 50: 50 forage: concentrate diet, addition of GAR (312 mg/L), DAD (31.2 and 312 mg/L), and ALM (31.2 and 312 mg/L) resulted in similar changes to those observed in batch culture, with the exception of the lack of effect of DAD on the proportion of propionate. In a third in vitro study, the potential of GAR (300 mg/L), DAD (300 mg/L), and ALM (300 mg/L) to decrease methane production was evaluated. Treatments GAR, DAD, and ALM resulted in a decrease in methane production of 73.6, 68.5, and 19.5%, respectively, compared with the control. These results confirm the ability of GAR, DAD, and ALM to decrease methane production, which may help to improve the efficiency of energy use in the rumen.
(25-Jan-2006)
 

Jalc D, Certik M (2005) Effect of microbial oil, monensin and fumarate on rumen fermentation in artificial rumen. Czech Journal of Animal Science 50 (10): 467-472

KEYWORDS: microbial oil; monensin; fumarate; rumen fermentation; artificial rumen; simulation-technique rusitec; fatty-acids; in-vitro; linseed oil; metabolism; sheep; microorganisms; efficiency; ruminants; corn

SUMMARY: The objective of this study was to investigate the effect of microbial oil on rumen fermentation of a diet composed of 60% hay and 40% barley in an artificial rumen (Rusitec). Microbial oil (MO) was produced by the fungus Thamnidium elegans. This fungus grew on the wheat bran/spent malt grains (3:1) mixture. The fatty acid composition of microbial oil was as follows: 0.7% C-14:0, 15.4% C-16:0, 10.1% C-18:0, 50.9% C-18:1, 13.9% C-18:2 and 8.4% C-18:3 (GLA, gamma-linolenic acid). The effect of monensin MON (66 ppm) and fumarate FUM (6.25 mmol) with and without MO supplementation was also studied. The experiment in Rusitec lasted 11 days. After a stabilization period (5 days), MO was added to fermentation vessel V-2 (6 days), MON to fermentation vessel V-3 (6 days) and FUM to fermentation vessel V-4 (6 days). MO was also added to V-3 and V-4 on the last day together with MON (V-3) and FUM (V-4). The fermentation vessel V-1 served as control (without additives). The results showed that MO reduced (P < 0.05) mol% acetate and increased (P < 0.05) mol% propionate and n-butyrate. Methane production (mmol/day) was reduced numerically (NS). The efficiency of microbial synthesis (EMS) was also reduced numerically and nitrogen incorporated by the microflora (N-M) was reduced significantly in MO supplementation. There were no differences in the rumen fermentation when MO was applied together with MON and FUM compared to the vessel where only MO was applied. No additive effect was observed in the relationship MO-ionophore or MO-FUM. Monensin and fumarate applied separately showed their typical effects on rumen fermentation in vitro.
(25-Jan-2006)
 

Gulati SK, Garg MR, Scott TW (2005) Rumen protected protein and fat produced from oilseeds and/or meals by formaldehyde treatment; their role in ruminant production and product quality: a review. Astralian Journal of Experimental Agriculture 45 (10): 1189-1203

KEYWORDS: formaldehyde-treated; rumen-protected nutrients; protein; milk; meat; conjugated linoleic-acid; lactating dairy-cows; treated soybean-meal; milk-production; dietary-protein; sunflower seed; tuna oil; sensory characteristics; nitrogen-utilization; concentrate diets

SUMMARY: The nutritional characteristics of rumen-protected protein and fat supplements produced by formaldehyde treatment of oilseeds and meals are reviewed. The proportion of rumen undegraded protein (RUP) in different protein sources can be controlled by this process, bio-available lysine is 82-84% and the proportions of acid detergent and neutral detergent insoluble nitrogen are unchanged by formaldehyde treatment; this is in contrast to heat treatment of proteins where significant increases in these nitrogen components can occur if the RUP content exceeds 60% of the crude protein (CP). A RUP content of 75-80% of CP is optimal when using protein supplements for milk production, and for body growth in steers a lower RUP content is desirable (i.e. 50-55% of CP). Both the fat and protein constituents in rumen-protected fat supplements derived from the emulsification and formaldehyde treatment of oilseeds are highly protected from ruminal metabolism (75-90%) and are readily digested in the small intestine (90% for C-18 unsaturated fatty acids, 82% for the essential amino acids). Protected fat/protein supplements are designed and fed to lactating and non-lactating ruminants to increase efficiency of production, enhance product quality, augment n-3, n-6 and n-9 fatty acid content of meat and milk, and to improve reproductive performance. The challenges and potential role for these protected fat/protein supplements in improving productivity and quality of ruminant derived foods are discussed.
(25-Jan-2006)
 

Liu JR, Yu B, Liu FH, Cheng KJ, Zhao X (2005) Expression of rumen microbial fibrolytic enzyme genes in Probiotic Lactobacillus reuteri. Applied and Environmental Microbiology 71 (11): 6769-6775

KEYWORDS: neocallimastix-patriciarum xylanase; thermocellum endoglucanase gene; beta-glucanase; bacillus-subtilis; escherichia-coli; alpha-amylase; plasmid dna; plantarum; cloning; cellulase

SUMMARY: This study was aimed at evaluating the cloning and expression of three rumen microbial fibrolytic enzyme genes in a strain of Lactobacillus reuteri and investigating the probiotic characteristics of these genetically modified lactobacilli. The Neocallimastix patriciarum xylanase gene xynCDBFV, the Fibrobacter succinogenes P-glucanase (1,3-1,4-beta-D-glucan 4-glucanohydrolase [EC 3.2.1.73]) gene, and the Piromyces rhizinflata cellulase gene eglA were cloned in a strain of L. reuteri isolated from the gastrointestinal tract of broilers. The enzymes were expressed and secreted under the control of the Lactococcus lactis lacA promoter and its secretion signal. The L. reuteri transformed strains not only acquired the capacity to break down soluble carboxymethyl cellulose, P-glucan, or xylan but also showed high adhesion efficiency to mucin and mucus and resistance to bile salt and acid.
(25-Jan-2006)

Graf CM, Kreuzer M, Dohme F (2005) Influence of supplementing hay to grass once or three times per day on the effectiveness of the fibre as determined by changes in ruminal pH, chewing activity and milk composition of cows Animal Research 54 (5): 321-335

KEYWORDS: ruminal pH fluctuation; chewing behaviour; feeding frequency; grass; fibre; lactating dairy-cows; forage particle-size; total mixed ration; feeding frequency; grazing behavior; rumen fermentation; herbage intake; holstein cows; cattle; concentrate

SUMMARY: Pasture grass in combination with or without 6 kg supplemental hay provided either once at 18: 00 h or in three equal portions per day (07:00, 13:00, 17:00 h), respectively, were tested in a 3 x 3 Latin square design in cows for its influence on the effectiveness of fibre through modifications of ruminal pH fluctuation, chewing activity and milk constituents. Six rumen cannulated cows (Brown Swiss: Holstein = 1:1, 32.9 kg milk center dot day(-1)) were tested in three periods consisting of 14 days of adaptation and 7 days of intensive data and sample collection. Chewing activity was recorded with the IGER Behavioural Recorder. Ruminal pH was measured continuously over 7 days by using an indwelling pH electrode and a data-recording unit, the latter being integrated in the cover of the cannula. The experimental treatment had no significant effect on milk yield and composition as well as ruminal pH fluctuation. The cows fed only grass spent 11% more time eating per day and 22% more time eating per kg neutral detergent fibre (NDF) than hay-supplemented cows, but no differences were observed in the time spent ruminating and ruminating time per kg dry matter and NDF. Across the complete day, the ruminal pH was non-significantly decreased by 0.1 when hay was supplied at once compared with the other treatments. Hay supplementations gave no advantage over grass-alone feeding with respect to variables assumed to respond to the effectiveness of fibre. By contrast, supplementing hay only once per day even seems to be inferior in maintaining a sufficiently high pH.
(25-Jan-2006)
 

Hollo G, Nuernberg K, Repa I, Hollo I, Seregi J, Pohn G, Ender K (2005) Effect of feeding on the composition of the intramuscular fat in longissimus muscle and different fatty tissues of Hungarian Grey and Holstein Friesian bulls. 1. Fatty acid profile Archiv Fur Tierzucht-Archives of Animal Breeding 48 (6): 537-546

KEYWORDS: bulls; fatty acid; CLA; muscle; fatty tissue; conjugated linoleic-acid; cattle; steers; diets; beef; quality; performance; nutrition; system; grass

SUMMARY: The aim of this study was to analyse the effect of nutrition, genotype and nutrition x genotype interaction on the fatty acid composition of intramuscular fat from longissimus dorsi muscle and different fat deposits using Hungarian Grey cattle bulls (HG) in comparison to Holstein Friesian bulls (HF) kept under extensive and intensive conditions. The extensive group was kept on pasture and was fed a concentrate supplemented with linseed meal in the last month of the trial. The extensive diet influenced the linoleic and linolenic acid ratio and the CLA content of longissimus muscle more advantageous concerning human nutrition. The meat from HG contained more CLA and less n-6 fatty acids also in case of the intensive diet than that of HF bulls. In the fat deposits from HF the PUFA mainly the linoleic acid was in a significant higher proportion available, however in the fat deposits of HG was the percentage of linol- and linolenic acid favourable. The extensive nutrition resulted in a lower linoleic acid and a higher linolenic acid content in both breeds and all three fat deposits. The PUFA content in the fat samples was altered contrary in both analysed breeds because of the different diet. In case of the extensive UG was the PUFA higher in all three fat deposits. In conclusion, the fatty acid composition of beef can be modified favourably by extensive feeding and concentrate which is rich in unsaturated fatty acids, however the beef of Hungarian Grey has a more wholesome influence on human health, than that of Holstein-Friesian bulls.
(25-Jan-2006)
 

Bourre JM (2005) Where to find omega-3 fatty acids and how feeding animals with diet enriched in omega-3 fatty acids to increase nutritional value of derived products for human: What is actually useful? Journal of Nutrition Health & Aging 9 (4): 232-242 2005

KEYWORDS: animal feeding; omega-3 fatty acids; polyunsaturated; diet; nutrition; aged; nutritional value; cost; fatty-acid-composition; alpha-linolenic-acid; randomized controlled-trials; docosahexaenoic-acid; fish-oil; adipose-tissue; dairy-cows; phospholipid supplementation; ethyl-esters; egg-yolk

SUMMARY: Omega-3 polyunsaturated fatty acids have two major field of interest. The first lies in their quantitative abundance and their role in the development and maintenance of the brain. The second is their role in the prevention of different pathologies, mainly the cardiovascular diseases, and more lately some psychiatric disorders, from stress to depression and dementia. Thus, dietary omega-3 fatty acids are very important to ensure brain structure and function, more specifically during development and aging. However, concerning essential alpha-linolenic acid (ALA), most occidental diets contain about 50% of the recommended dietary allowances. The problem is to know which foods are naturally rich in this fatty acid, and to determine the true impact of the formulations (enriched in omega-3 fatty acids, either ALA or EPA and DHA) used in cows on farms and breeding centres on the nutritional value of the products (meat, butter, milk and dairy products, cheese, and eggs, etc), and thus their effect on the health of consumers, especially to ensure adequate quantities in the diet of the aging people. The consequences (qualitative and quantitative) of modifications in the composition of animal foods on the value of derived products consumed by humans are more marked when single-stomach animals are concerned than multi-stomach animals. Because, for example, hydrogenating intestinal bacteria of the latter group transform a large proportion of polyunsaturated fatty acids in their food into saturated fatty acids, among others, thus depriving them of any biological interest. Under the best conditions, by feeding animals with extracts of linseed and rapeseed grains for example, the level of ALA acid is increased approximately two-fold in beef and six-fold in pork, ten-fold in chicken, and forty-fold in eggs. By feeding animals with fish extracts or algae (oils) the level of DHA is increased about 2-fold in beef, 7-fold in chicken, 6-fold in eggs, and 20-fold in fish (salmon). To obtain such results, it is sufficient to respect only the physiological needs of the animal, which was generally the case with traditional methods. It is important to stress the role of fish, whose nutritional value for humans in terms of lipids (determined by omega-3 fatty acid levels) can vary considerably according to the type of fats the animals have been fed. The aim of preventing some aspects of cardiovascular disease (and other pathologies) can be achieved, or on the contrary frustrated, depending on the nature of fatty acids present in fish flesh, the direct consequence of the nature of fats with which they have been fed. It is the same for eggs, "omega-3 eggs" being in fact similar to natural eggs, were used in the formulation of certain formula milks for infants, whose composition was closest to that of breast milk. In fact, the additional cost on the price paid by the consumer is modest compared to the considerable gain in nutritional value in terms of omega-3 fatty acids content. Interestingly, in aged people, ALA recommendations in France are increased (0.8% daily energy intake in adult, 0.9% in aged) and DHA is multiplied by 2 (0.05% daily energy intake in adult, 0.1% in aged; as well as in pregnant and lactating women).
(25-Jan-2006)
 

Kim YS, Liang CY, Song YH, Lee SK (2006) Effects of dietary Rhus verniciflua stokes supplementation on meat quality characteristics of Hanwoo (Korean cattle) beef during refrigerated storage Asian-Australasian Journal of Animal Sciences 19 (1): 113-118

KEYWORDS: Rhus verniciflua stokes; color; WHC; TBARS; fatty acid composition; Hanwoo; color stability; ground-beef; antioxidant; acid; capacity; extract; tissues; time; pork

SUMMARY: The effects of dietary Rhus verniciflua Stokes (Plant used in herbal medicine in Korea with reported antioxidant and cytotoxic effects - see Lee et al, Journal of Biochemistry and Molecular Biology, Vol. 34, No. 3, May 2001, pp. 250-258) supplementation (0%, 2%, 4% and 6%/feed) on meat color, water-holding capacity (WHC), lipid oxidation and fatty acid composition in m. longissimus from Hanwoo (Korean cattle) beef during refrigerated storage were investigated. The L*, a*, b* and C* values of 4% group were significantly (p < 0.05) higher than those of the other groups for 7 days of storage. The a*, b* and C* values declined gradually during storage in all of the groups and the decline was more rapid in control group. The metmyoglobin (%) was significantly (p < 0.05) increased during storage time in all of the groups, but the 4% group had a lower rate of metmyoglobin accumulation during storage. WHC was significantly (p < 0.05) higher in the 2% and 4% groups than in the other groups. The TBARS (thiobarbituric acid reactive substances) value of day 0 was not significantly (p > 0.05) different among 4 diet conditions, but the TBARS value after 5 days of storage was significantly (p < 0.05) higher in the control group than in other groups. The proportions of C18:1, MUFA, UFA and MUFA/SFA ratio were significantly (p < 0.05) higher in the meat from Rhus verniciflua Stokes-supplemented Hanwoo than in the control group. Consequently, the meat from Rhus verniciflua Stokes-supplemented Hanwoo showed higher color stability, WHC, unsaturated fatty acids and retarded lipid oxidation compared to the control meat. In particular, dietary Rhus verniciflua Stokes supplementation with 4% extended storage life compared to the other groups.
(25-Jan-2006)
 

Chumpawadee S, Sommart K, Vongpralub T, Pattarajinda V (2006) Effects of synchronizing the rate of dietary energy and nitrogen release on ruminal fermentation, microbial protein synthesis, blood urea nitrogen and nutrient digestibility in beef cattle. Asian-Australasian Journal of Animal Sciences 19 (2): 181-188

KEYWORDS: beef cattle; dietary energy; microbial protein; synchrony index; nutrient digestibility; lactating dairy-cows; rumen fermentation; feeding frequency; organic-matter; crude protein; sheep; carbohydrate; degradation; metabolism; pasture

SUMMARY: The objective of this research was to determine the effects of synchronizing the rate of dietary energy and nitrogen release on: ruminal fermentation, microbial protein synthesis, blood urea nitrogen, and nutrient digestibility in beef cattle. Four, two-and-a-half year old Brahman-Thai native crossbred steers were selected for the project. Each steer was fitted with a rumen cannula and proximal duodenal cannula. The steers were then randomly assigned in a 4x4 Latin square design to receive four dietary treatments. Prior to formulation of the dietary treatments, feed ingredients were analyzed for chemical composition and a nylon bag technique was used to analyze the treatments various ingredients for degradability. The treatments were organized in four levels of a synchrony index (0.39, 0.50, 0.62 and 0.74). The results showed that dry matter digestibility trend to be increased (p < 0.06), organic matter and acid detergent fiber digestibility increased linearly (p < 0.05), while crude protein and neutral detergent fiber digestibility were not significantly different (p > 0.05). Higher concentration and fluctuation of ruminal ammonia and blood urea were observed in the animal that received the lower synchrony index diets. As the levels of the synchrony index increased, the concentrations of ruminal ammonia nitrogen and blood urea nitrogen, at the 4 h post feeding, decreased linearly (p < 0.05). Total volatile fatty acid and bacteria populations at the 4 h post feeding increased linearly (p < 0.05). Microbial protein synthesis trend to be increase (p < 0.08). The results of this research indicate that synchronizing the rate of degradation of dietary energy and nitrogen release improves ruminal fermentation, microbial protein synthesis and feed utilization.
(25-Jan-2006)

Verbic J, Babnik D, Znidarsic-Pongrac V, Resnik M, Gregorcic A, Kmecl V (2005) The effect of dent versus flint maize genotype on site and the extent of starch and protein digestion, ruminal fermentation and microbial protein synthesis in the rumen of sheep. Animal Research 54 (6): 443-458

KEYWORDS: maize silage; starch digestion; protein digestion; microbial protein; sheep; lactating dairy-cows; milk-yield; mechanistic model; fiber digestion; large-intestine; particle-size; beef steers; dry-matter; corn grain; degradation

SUMMARY: Ruminal and whole tract digestibility of protein and starch, microbial protein yield in the rumen and molar proportions of volatile fatty acids ( VFA) in the rumen fluid and faeces were determined in sheep that were given either maize silage derived from the dent ( DTS) or flint type hybrid ( FTS). Degradabilities in the rumen were determined by means of the in sacco method using three sheep and microbial protein yield in the rumen by means of urinary purine derivative excretion using four sheep. The extent of starch and protein degradation was significantly ( P < 0.001) lower in FTS than in DTS ( 718 vs. 913 and 704 vs. 767 g . kg(-1) respectively). Differences in whole tract starch and protein digestibility were small ( 986 vs. 997, P < 0.01 and 939 vs. 931 g . kg(-1), P < 0.05 in FTS and DTS respectively). The concentration of VFA in the rumen fluid was not affected by the type of silage ( 94.5 and 94.7 mmol . L-1); however, FTS induced a higher molar proportion of propionate ( 22.6% vs. 20.7%, P < 0.05) than DTS. The proportion of butyrate was higher in DTS ( 13.5% vs. 10.8%, P < 0.05). Microbial protein supply in FTS was significantly higher than in DTS ( 109.7 vs. 96.0 g . kg(-1) DM intake, P < 0.05). When expressed in relation to fermentable organic matter ( FOM) intake, the differences between hybrids were greater ( 215.6 vs. 158.6 g of microbial protein per kg FOM, P < 0.01). Lower efficiency of microbial protein synthesis in DTS was probably due to a lower pH value of rumen liquor ( 6.21 vs. 6.33, P < 0.05). FTS offered better conditions for the degradation of the fibre fraction in the rumen than DTS. The faeces of sheep that were given FTS contained less DM ( 304 vs. 371 g . kg(-1), P < 0.05) and tended to have a higher concentration of VFA ( 383 and 235 mmol . kg(-1) DM, P < 0.1) indicating that in FTS at least one part of the starch which escaped digestion in the rumen passed through the small intestine undigested and was fermented in the large intestine. It was concluded that FTS could provide about three times more postruminally digested starch and about 20% more metabolisable protein than DTS.
(25-Jan-2006)
 

Weiss WP, Hogan JS (2005) Effect of selenium source on selenium status, neutrophil function, and response to intramammary endotoxin challenge of dairy cows. Journal Of Dairy Science 88 (12): 4366-4374

KEYWORDS: selenium; neutrophils; mastitis; dairy cow; vitamin-e; glutathione-peroxidase; maternal transfer; dietary selenium; holstein cows; beef-cows; blood; supplementation; calves; yeast

SUMMARY: The effects of feeding dry and early lactation dairy cows diets with selenate or selenized yeast (Se-yeast) on concentrations of Se in serum, milk, and newborn calves, neutrophil function, and inflammatory response were determined. At 60 d before anticipated calving until approximately 30 d in milk (DIM), cows were fed diets that contained 0.3 mg of supplemental Se/kg of DM from sodium selenate or Se-yeast. Diets also contained 0.2% supplemental S (as sulfate) because it has been shown to reduce absorption of Se by dairy cows. The concentration of Se in serum at calving and 28 DIM was about 1.4 times greater for cows fed Se-yeast than for those fed selenate. Serum concentrations decreased 45 and 23% from dry-off to calving for cows fed selenate or Se-yeast, respectively. Selenium concentrations in serum from newborn calves were also about 1.4 times greater when the dams were fed Se-yeast. Concentrations of Se in colostrum and milk were about 1.8 times greater when cows were fed Se-yeast. Blood neutrophils were isolated from cows at 28 DIM and were used in an in vitro kill assay. Selenium treatment did not affect bacterial kill or the percentage of neutrophils that phagocytized bacteria. At approximately 28 DIM, one quarter from each cow was infused with a solution containing endotoxin. Peak body temperature (40.7 degrees C) occurred 6 h postinfusion, and peak somatic cell count (6.5 log(10)/mL) occurred at 12 h postinfusion. Neither measure was influenced by Se treatment.
(25-Jan-2006)

Baublits RT, Brown AH, Pohlman FW, Rule DC, Johnson ZB, Onks DO, Murrieta CM, Richards CJ, Loveday HD, Sandelin BA, Pugh RB (2006) Fatty acid and sensory characteristics of beef from three biological types of cattle grazing cool-season forages supplemented with soyhulls Meat Science 72 (1): 100-107

KEYWORDS: beef; forage-fed; soyhulls; fatty acids; CLA; flavor; conjugated linoleic-acid; carcass composition; flavor; steers; palatability; muscle; grain; tenderness; profiles; quality

SUMMARY: Over two consecutive years, the effects of allocating divergent biological types of cattle (n = 107) to fescue pasture without supplementation, or fescue or orchardgrass pasture with soyhull supplementation on chemical, fatty acid and sensory characteristics were investigated. Cattle from the two supplemented treatments produced beef that had increased (P < 0.05) percentage lipid and decreased (P < 0.05) polyunsaturated and n-3 fatty acids compared to the control. However, the n-6 to n-3 ratio was still less than four in beef from the supplemented cattle. Additionally, supplementation did not decrease (P > 0.05) the CLA present in the longissimus, which can commonly occur when forage-fed cattle are supplemented concentrates. Although supplementation did not impact (P > 0.05) Warner-Bratzler shear force or tenderness, supplementation of soyhulls reduced (P < 0.05) the grassy flavor intensity of rib steaks when compared to the control. Biological type did not have a significant influence on most traits analyzed in this study. These results suggest that supplementation of soyhulls to cattle grazing forage can reduce grassy flavor intensity without decreasing CLA proportions, but can reduce the n-3 fatty acid proportions present in the longissimus.
(25-Jan-2006)
 

Lawrence RW, Doyle J, Elliott R, Loxton I, McMeniman JP, Norton BW, Reid DJ, Tume RW (2006) The efficacy of a vitamin D-3 metabolite for improving the myofibrillar tenderness of meat from Bos indicus cattle Meat Science 72 (1): 69-78

KEYWORDS: Brahman cattle; 25-hydroxyvitamin D-3; myofibrillar meat tenderness; muscle calcium; muscle magnesium; muscle iron; plasma calcium; plasma magnesium; beef tenderness; postmortem storage; quality traits; supplementation; carcass; calcium; muscle; tenderization; proteases; injection

SUMMARY: Vitamin D3 administration to cattle pre-slaughter was reported to elevate muscle calcium concentrations and activate residual m-calpain, resulting in increased levels of post-mortem proteolysis and subsequent improvement in tenderness (Swanek et al., 1999).The influence of a once only administration of a metabolite of vitamin D-3 (HY • D®-25-hydroxy vitamin D3) on myofibrillar meat tenderness in Australian Brahman cattle was studied. Ninety-six Brahman steers of three phenotypes (indo-Brazil, US and US/European) and with two previous hormonal growth promotant (HGP) histories (implanted or not implanted with Compudose(®) were fed a standard feedlot ration for 70 d. Treatment groups of 24 steers were offered daily 10 g/head HY • D®-25-hydroxy vitamin D3 (125 mg 25-hydroxyvitamin D-3) for 6, 4, or 2 d before slaughter. One other group of 24 steers was given the basal diet without HY • D®-25-hydroxy vitamin D3. Feed lot performance, blood and muscle samples and carcass quality data were collected at slaughter. Calcium, magnesium, potassium, sodium, iron and Vitamin D-3 metabolites were measured in plasma and longissimus dorsi muscle. Warner-Bratzler (WB) shear force (peak force, initial yield) and other objective meat quality measurements were made on the longissimus dorsi muscle of each steer after ageing for 1, 7 and 14 d post-mortem at 0-2 degrees C.
There were no significant effects of HY • D®-supplements on average daily gain (ADG, 1.28-1.45 kg/d) over the experimental period. HY • D®-supplements given 6 d prior to slaughter resulted in significantly higher (P < 0.05) initial yield values compared to supplements given 2 d prior to slaughter. Supplementation had no significant effect on meat colour, ultimate pH, sarcomere length, cooking loss, instron compression or peak force. There was a significant treatment (HY • D®-25-hydroxy vitamin D3) by phenotype/HGP interaction for peak force (P = 0.028), in which Indo-Brazil steers without previous HGP treatment responded positively (increased tenderness) to HY • D®- supplements at 2 d when compared with Indo-Brazil steers previously given HGP. There were no significant effects of treatment on other phenotypes. HY • D®-supplements did not affect muscle or plasma concentrations of calcium, potassium or sodium, but did significantly decrease plasma magnesium and iron concentrations when given 2 d before slaughter. There were no detectable amounts of 25-hydroxyvitamin D-3 in the blood or muscle of any cattle at slaughter.
(25-Jan-2006)

Lefebvre B, Diarra MS, Giguere K, Roy G, Michaud S, Malouin F (2005) Antibiotic resistance and hypermutability of Escherichia coli O157 from feedlot cattle treated with growth-promoting agents. Journal of Food Protection 68 (11): 2411-2419

KEYWORDS: field gel-electrophoresis; hemolytic-uremic syndrome; shiga toxin; mutation frequencies; enterococcus-faecium; virulence factors; strains; humans; prevalence; bacteria

SUMMARY: In a longitudinal study (165 days), we investigated the effect of growth-promoting agents (monensin and trenbolone acetate-estradiol) and an antibiotic (oxytetracycline) on the incidence in feedlot steers of Escherichia coli O157, including antibiotic-resistant and hypermutable isolates. Eighty steers in 16 pens were treated with eight combinations of promoters, and each treatment was duplicated. Fecal samples were collected at nine different sampling times for detection of E. coli O157. Overall, 50 E. coli O157 isolates were detected in treated animals, and none were found in untreated animals. Compared with untreated controls, there was a significant association between the utilization of growth-promoting agents or antibiotics and the shedding of E. coli O157 at day 137 (P = 0.03), when a prevalence peak was observed and 50% of the isolates were detected. Multiplex PCR assays were conducted for some virulence genes. PCR results indicated that all except one isolate possessed at least the Shiga toxin gene stx2. MICs for 12 antibiotics were determined, and eight oxytetracycline-resistant E. coli O157 strains were identified. Antibiotic-resistant strains were considered a distinct subpopulation of E. coli O157 by pulsed-field gel electrophoresis typing. Seven of these antibiotic-resistant strains were isolated early in the study (on or before day 25), and among them two were also hypermutable as determined by rifampin mutation frequencies. The proportion of hypermutable strains among E. coli O157 isolates remained relatively constant throughout the study period. These results indicate that the use of growth-promoting agents and antibiotics in beef production may increase the risk of environmental contamination by E. coli O157.
(25-Jan-2006)
 

Cusak P.M.V., McMeniman N.P., Lean I.J. (2005) “The physiological and production effects of increased dietary intake of vitamins E and C in feedlot cattle challenged with bovine herpesvirus 1”. Journal of Animal Science 83:2423-2433.

KEYWORDS: BHV1; beef cattle; nutrition

SUMMARY: The physiological and production effects of feeding additional vitamin E and ruminally protected vitamin C were examined in cattle challenged with bovine herpesvirus 1 (BHV1). 48 individually penned 6-mo-old Angus and Angus crossbred heifer calves with a mean BW of 151 kg were allocated randomly to 4 diets in a 2x2 factorial arrangement of treatments. Pelleted diets provided either 15 or 185 IU/kg of DM of vitamin E, with or without 3.7 g of ruminally protected vitamin C /kg of DM. Blood samples were taken at start of the experiment and at wk 4, 5, and 6. At the start of wk 5, half of each of the dietary groups was challenged with BHV1. Feeding additional vitamin E was associated with greater mean plasma alpha-tocopherol. In contrast, feeding ruminally protected vitamin C was not associated with greater mean plasma ascorbate concentration; however, feeding ruminally protected vitamin C was associated with lower mean blood total superoxide dismutase concentration. Calves fed additional vitamin E had greater mean plasma beta-carotene concentrations. There were interactions between dietary intake of vitamins E and C with respect to serum ceruloplasmin concentration and G:F. BHV1 challenge was associated with lower white cell count, lymphocyte count, and DMI. Feeding additional vitamin E to calves challenged with BHV1 was associated with a lower serum ceruloplasmin concentration. There was a non-significant trend towards an interaction between the feeding of vitamins E and C, with virus-challenged calves fed additional vitamin E alone having greater plasma retinol concentrations. The feeding of vitamins E and/or C in calves challenged with BHV1 was associated with alterations in the concentrations of other antioxidants. More severe disease may have translated these cellular effects to changes in health and performance.
(25-Jan-2006)
 

Adewuyi A.A., Gruys E., van Eerdenburg F.J.C.M. (2005) “Non esterified fatty acids (NEFA) in dairy cattle. A review”. Veterinary Quarterly 27:117-126.

KEYWORDS: energy balance; high yielding dairy cows; NEFA; review

SUMMARY: This study aims to review the literature on elevated blood concentrations of nonesterified fatty acids (NEFA) before and after parturition in high-yielding dairy cows. It highlights the factors that influence serum NEFA production and their circulation before and after parturition, such as adaptation for nutrient partitioning for fetal needs, onset of lactogenesis, stress of calving and numerous changes in physiological, metabolic, and endocrine status to accommodate parturition and lactogenesis. The role of NEFA in the liver and peripheral tissues and its toxic effects when in excess are discussed. The cow's adaptive physiologic mechanisms to prevent or decrease excessive values of serum NEFA and preventive and therapeutic interventions to enhance these mechanisms are categorized as natural and artificial antidotes respectively. Feeding systems during the dry period and daily exercise or walking activity which may burn excessive NEFA through beta-oxidation in the muscles are considered as more useful antidotes to managing the NEFA metabolism. This will minimize accumulation of lipids in the liver during early lactation and alleviate the negative effects of plasma NEFA leading to more optimal metabolic health and productivity of dairy cows.
(25-Jan-2006)

Chavez A.S., Gese E.M. (2005) “Food habits of wolves in relation to livestock depredations in northwestern Minnesota”. American Midland Naturalist 154:253-263.

KEYWORDS: feeding behaviour; wolf; US; depredation

SUMMARY: Wolves have recolonized many areas of the Midwestern United States, prompting concern over the possible risk wolves may pose to livestock producers. To better understand these risks, a 3-yr study was initiated examining wolves food habits in agricultural areas of northwestern Minnesota and their relation to depredation records of livestock losses in the same area. 533 wolf feces were collected during the non-winter seasons from 1997-1999. White-tailed deer was the most abundant food item (39%) of all prey items for all 3 yr combined. The deer component comprised both adult deer (27%) and fawns (12%). Muskrats were the second highest food item at 17%. Moose, both adults (13%) and calves (1%), comprised 14% of the wolves diet, followed by cattle (10%), domestic pig (4%), lagomorphs (4%) and beaver (2%). Within the study area, 8 head of livestock were officially reported as wolf depredations. The confirmed losses included 1 sheep, 1 injured cow, 1 blind cow and 5 calves. Even with very low deer and moose densities in the study area and a high preponderance of cattle in the area (> 1000 head), the wolves in the area preyed mostly on native prey species.
(7-Nov-2005)

Li JY, Suzuki K, Koike Y, Chen DS, Yonezawa T, Nishihara M, Manabe N (2005) Effects of dietary supplementation with branched-chain amino acids (BCAAs) during nursing on plasma BCAA levels and subsequent growth in cattle. Asian-Australasian Journal Of Animal Sciences 18 (10): 1440-1444

KEYWORDS: branched-chain amino acid; plasma concentration; average daily gain; carcass weight; cattle; diabetic mothers; leucine; muscles; glucose; infants; tissue; rats
SUMMARY: To determine the effects of short-term dietary supplementation of branched-chain amino acids (BCAAs) during nursing (from 3 to 28 days of age) on plasma BCAA levels and subsequent growths in cattle, 12 nursing male Holstein calves, randomly assigned to control and treatment groups (n = 6 in each group), orally received a daily supplement of essential BCAAs (2 g/kg body weight/day; 1:1:1 of valine, leucine and isoleucine) or not. The plasma BCAA levels increased linearly after the administration. During the treatment period, average daily gain (ADG) was lower in the treatment group (0.43+/-0.07 kg/day) than the controls (0.71+/-0.07 kg/day, p<0.05). However, at 2 months of age, ADG was significantly higher in the BCAA-treated group (1.16+/-0.26 kg/day vs. 0.51+/-0.06 kg/day, p<0.05). Furthermore, at age 8, 9 and 10 month, ADG in the treated group (1.35+/-0.23, 1.46+/-0.07 and 1.60+/-0.16 kg/day, respectively) showed a linear increase and was significantly higher than that in the control group (0.88+/-0.14, 0.70+/-0.21 and 1.11+/-0.11 kg/kg, respectively, p<0.05). Overall, ADG was 15.6% higher in the treatment group (1.26+/-0.05 kg vs. 1.09+/-0.04 kg; p<0.05). The final body weight at slaughter was 14.8% higher in the treatment group (759.5+/-17.7 kg vs. 661.7+/-21.2 kg, p<0.01). Thus, the supplementation of BCAAs during nursing improves ADG and carcass weight in cattle and is a useful husbandry technique for beef cattle.
(6-Sept-2005)
  

Henrique DS, Vieira RAM, Malafaia PAM, Mancini MC, Goncalves AL (2005) Estimation of the total efficiency of metabolizable energy utilization for maintenance and growth by cattle in tropical conditions. Revista Brasileira De Zootecnia - Brazilian Journal of Animal Science 34 (3): 1006-1016

KEYWORDS: bioenergetics; growth; net energy; ruminants; dynamic-model; steers; system; values

SUMMARY: Data of 320 animals were obtained from eight comparative slaughter studies performed under tropical conditions and used to estimate the total efficiency of utilization of the metabolizable energy intake (MEI), which varied from 77 to 419 kcal kg(-0.75) d(-1). The provided data also contained direct measures of the recovered energy (RE), which allowed calculating the heat production (HE) by difference. The RE was regressed on MEI and deviations from linearity were evaluated by using the F-test. The respective estimates of the fasting heat production and the intercept and the slope that composes the relationship between RE and MEI were 73 kcal kg-0.75 d(-1), -42 kcal kg-(0.75) d(-1) and 0.37. Hence, the total efficiency was estimated by dividing the net energy for maintenance and growth by the metabolizable energy intake. The estimated total efficiency of the ME utilization and analogous estimates based on the beef cattle NRC model were employed in an additional study to evaluate their predictive powers in terms of the mean square deviations for both temperate and tropical conditions. The two approaches presented similar predictive powers but the proposed one had a 22% lower mean squared deviation even with its more simplified structure.
(6-Sept-2005)
  

Bahar B, Monahan FJ, Moloney AP, O'Kiely P, Scrimgeour CM, Schmidt O (2005). Alteration of the carbon and nitrogen stable isotope composition of beef by substitution of grass silage with maize silage. Rapid Communications in Mass Spectrometry 19 (14): 1937-1942

KEYWORDS: nuclear-magnetic-resonance; ratio mass-spectrometry; origin assignment; geographic origin; natural-abundance; animal products; diet; fractionation; milk; meat

SUMMARY: This study investigated the effect of substituting grass silage (C-3 photosynthetic plant product) with maize silage (C-4 photosynthetic plant product) on the natural abundance carbon (delta(13)C) and nitrogen (delta(15)N) stable isotope composition of bovine muscle tissue. Forty-five continental crossbred heifers were assigned to one of three diets consisting of 3kg of a barley-based concentrate plus grass silage, maize silage or an equal mixture (dry matter basis) of grass silage and maize silage, fed ad libitum, for 167 days. Substitution resulted in less negative delta(13)C values (P < 0.001) in lipid-free muscle and in lipid, and also a lower delta(15)N (P < 0.001) in lipid-free muscle. Feeding of maize silage was clearly reflected in the delta(13)C of muscle, with each 10% difference in the dietary C-4 carbon intake resulting in a 0.9 to 1.0%. shift of delta(13)C in lipid-free muscle and a 1.0 to 1.2 parts per thousand in lipid. Minimum detectable mean differences (95% confidence, power 0.80, n = 15) in this experiment were about 0.5 parts per thousand and 1.0 parts per thousand for delta(13)C of lipid-free muscle and lipid, respectively, and about 0.5 parts per thousand for delta(15)N of lipid-free muscle. The power analysis presented here is useful for estimating minimum isotopic differences that can be detected between any two groups of beef samples with a given number of replicates. It is concluded that carbon stable isotope ratio analysis of meat can be used to quantify C-3/C-4 dietary constituents in beef production.
(6-Sept-2005)
  

Huhtanen P (2005) Critical aspects of feed protein evaluation systems for ruminants. Journal of Animal and Feed Sciences 14: 145-170 Suppl. 1

KEYWORDS: protein evaluation; systems; empirical models; ruminants; lactating dairy-cows; mobile-bag method; grass-silage; milk-production; nitrogen degradability; rumen fermentation; passage kinetics; amino-acids; digestion; digestibility

SUMMARY: The current feed protein evaluation systems taking into account the amount of amino acids absorbed from the small intestine are critically reviewed. Especially the differences in the concepts of estimating protein values and limitations of techniques used to estimate parameter values are discussed. Validation of different approaches to estimate the microbial component of metabolizable protein using data from production experiments was conducted. The review is focused on empirical models based on factorial approaches. In the future, the mechanistic models, which can better take into account interactions in the digestive tract and tissue metabolism, should be developed.
(6-Sept-2005)
  

Kamiya Y., Kamiyal M., Tanakal M., Shioya S. (2005) “Effects of calcium intake and parity on plasma minerals and bone turnover around parturition”. Animal Science Journal, (76), 4 pp 325-330

KEYWORDS: bone, dairy cow, dietary calcium, parity, parturition

SUMMARY: Eight pregnant heifers (primiparous cows) and seven pregnant cows in their second, third and forth pregnancies (multiparous cows) were assigned to two groups and fed either a low calcium (Ca) diet (Ca, 0.46%) or a high Ca diet (Ca, 0.86%) ad libitum from 3 weeks before the expected calving date to 3 days after parturition. All cows were examined for a change in dry matter intake (DMI), plasma minerals and bone turnover around parturition. The dietary Ca level did not affect the DMI in both primiparous and multiparous cows. The DMI of primiparous cows was significantly lower than that of multiparous cows (P < 0.05) in both the low and high dietary Ca groups. The dietary Ca level did not affect the concentrations of plasma Ca, phosphorus, magnesium and parathyroid hormone throughout the experimental period. Plasma phosphorus in primiparous cows was significantly higher (P < 0.05) than that of multiparous cows around parturition. Plasma Ca and magnesium tended to be higher (P < 0.10) in primiparous cows. The dietary Ca level did not affect the plasma osteocalcin (OC) level measured as bone formation or the urinary deoxypyridinoline (DPD) excretion measured as bone resorption before parturition in both primiparous and multiparous cows. After parturition, the plasma OC level was lower than it was before parturition in multiparous cows fed a low Ca diet, and in primiparous cows. There were no significant differences in urinary DPD excretion between each group before and after parturition. Both the plasma OC level and urinary DPD excretion of primiparous cows were significantly higher than those of multiparous cows in both the low and high dietary Ca groups.
(6-Sept-2005)
  

Prache S., Cornu A., Berdagué J. L., Priolo A. (2005) “Traceability of animal feeding diet in the meat and milk of small ruminants”. Small Ruminant Research, (59), 2-3 pp 157-168

KEYWORDS: authentication, meat, milk, sheep, traceability

SUMMARY: Supplying the consumers with guarantees concerning the feed given to animals needs reliable methods for characterizing meat and milk. Bodies operating product certification systems also require control tools, to be able to guarantee objectively that specification commitments have been fully met. This paper reviews the current state of knowledge concerning the traceability of animal feeding diets in the meat and milk of small ruminants. It presents the potential tracers and different methods that have been studied, together with recent results. Plant biomarkers such as carotenoids, terpenes and phenolic compounds, animal metabolites such as 2,3-octanedione, skatole, fatty acids and ratios of oxygen, carbon and nitrogen stable isotope, are potential tracers in meat and milk or animal tissues, of animal feeding diets. Terpenes, phenolic compounds and ratios of stable isotope are also potential tracers of the geographical origin of milk and meat. Global approaches, especially near infrared spectroscopy and functional genomics are just emerging and need further experimental evaluation. These techniques already allowed to discriminate among products obtained in contrasting feeding conditions. Intermediate situations, for example, in case of modification of animal's diet, may be less easily recognized and may require the combination of tracing methods. In particular, the persistence of tracers when animals are stall-fed a concentrate-based diet after pasture, and its implications for traceability are discussed. Further directions for research are finally highlightened.
(6-Sept-2005)
 

Chichlowski M. W., Schroeder J. W., Park C. S., Keller W. L., Schimek D. E. (2005) “Altering the Fatty Acids in Milk Fat by Including Canola Seed in Dairy Cattle Diets”. Journal of Dairy Science, (88), 9 pp 3084-3094

KEYWORDS: canola seed, fatty acid, conjugated linoleic acid, dairy cow

SUMMARY: The objective was to evaluate the effects of feeding ground canola seed on the fatty acid profile, yield, and composition of milk from dairy cows. Twenty-four multiparous Holstein cows (548.3 ± 11.9 kg body weight and 28 ± 9 d in lactation) were randomly assigned to 1 of 2 treatments: Control (CON) or ground canola seed treatment (GCS) with 14% [of diet dry matter (DM)] of the total ration as ground canola seed containing 34% lipid. Diets contained 20% crude protein, but varied in net energy as a result of fat content differences of 2.5% and 6.4% (DM) for CON and GCS, respectively. Diets were composed of corn, corn silage, alfalfa (50:50 ground hay and haylage, DM basis), soybean and blood meal, and vitamins and minerals. Mechanically extruded canola meal was used in the CON diet to adjust for the protein from canola seed in the GCS diet. Cows were housed in tie-stalls and fed and milked twice daily for 10 wk. The inclusion of ground canola seed did not alter DM intake, weight gain, or body condition score of cows. Milk fat from GCS cows had greater proportions of long-chain fatty acids ( 18 carbons) and a lower ratio of n-6 to n-3 fatty acids. Feeding GCS reduced the proportion of short- and medium-chain fatty acids. Milk fat from cows fed GCS had a greater proportion of vaccenic acid and tended to have a higher proportion of cis-9,trans-11 conjugated linoleic acid. Actual and 3.5% fat-corrected milk yields were similar between treatments. The milk fat and protein percentages were lower for GCS cows, but total yield of these components was similar between treatments. Milk urea nitrogen was lower and serum urea nitrogen tended to be lower in cows fed canola seed. Serum glucose, insulin, and nonesterified fatty acids were not altered, but serum triglycerides were higher in GCS cows. Ammonia and total volatile fatty acids tended to be lower in ruminal fluid from GCS cows; rumen pH was unchanged. Feeding canola seed to lactating dairy cows resulted in milk fat with higher proportions of healthful fatty acids without affecting milk yield or composition of milk.
(6-Sept-2005)  

Gomez JA, Tejido ML, Carro MD (2005) Influence of disodium malate on microbial growth and fermentation in rumen-simulation technique fermenters receiving medium- and high-concentrate diets. British Journal of Nutrition 93 (4): 479-484

KEYWORDS: malate, rumen fermentation, microbial protein synthesis, RUSITEC, keywords plus: ruminal microorganism fermentation, bacterium selenomonas-ruminantium, in-vitro, methane production, organic-acids, technique rusitec, dl-malate, fumarate, forage, fiber

SUMMARY: Two incubation trials were carried out with the rumen-simulation technique RUSITEC. In each trial, four vessels received a diet of grass hay and concentrate (600 and 400 g/kg DM, respectively; diet F), and the other four were fed a diet composed of concentrate and barley straw (900 and 100 g/kg DM, respectively; Diet C). Vessels were given 20 g of the corresponding diet daily, and half of them were supplemented with disodium malate to achieve a final concentration of 6.55 mM. There were no effects (P < 0.05) of malate either on pH or on the daily production of NH3-N, but malate treatment increased (P < 0.05 DM), neutral detergent and acid detergent fibre disappearance after 48 h incubation. The daily production of propionate and butyrate increased (P < 0.001), and the ratio CH4:volatile fatty acids decreased (P < 0.001) by supplementing both diets with malate. Whereas adding malate to the F diet produced an increase in acetate production (P = 0.011) and the growth of solid-associated micro-organisms (P = 0.037), no effects (P > 0.05) were observed for diet C. For both diets, there were no differences (P > 0.05) between treatments in the daily flow of liquid-associated micro-organisms measured using N-15 as a microbial marker. These results indicate that malate stimulated the in vitro fermentation of both diets by increasing the apparent disappearance of the diet and decreasing the ratio of CH4:volatile fatty acids, but a greater response was observed with diet F. If these results are confirmed in vivo, malate could be used as a feed additive for ruminants fed diets containing medium proportions of forage i.e. dairy animals and not only in animals fed high-concentrate diets, as has so far been proposed.
(30-June-2004)
 

Kamalak A, Canbolat O, Gurbuz Y, Ozay O (2005) Prediction of dry matter intake and dry matter digestibilities of some forages using the gas production technique in sheep. Turkish Journal of Veterinary & Animal Sciences 29 (2): 517-523

KEYWORDS: digestibility, food intake, gas production, sheep, nylon bag degradability, voluntary intake, in-vitro, degradation characteristics, apparent digestibility, mature ewes, rumen, parameters, roughages, incubation

SUMMARY: Wheat straw, barley straw, alfalfa hay, alfalfa silage and maize silage were offered ad libitum to three male sheep, and daily dry matter intake (DMI) and apparent dry matter digestibility (DMD) were measured. Samples of forages were incubated with rumen fluid to determine gas production. Gas productions were measured at 3, 6, 12, 24, 48, 72 and 96, and gas production constants (a, b, c,) were described using the equation y = a + b (1 - e-(ct)). Gas production at all incubation times and gas production constants (c, b and a+b) were significantly (P < 0.001) correlated to DMD or DMI. Although the gas production constant c explained 74% of the variation of DMD, the gas production constant b explained 92% of the variation of DMD. The gas production constants c and (a+b) in combination explained 96% of the variation of DMD. The gas production constants b and c alone explained 70% and 78% of the variation of DMI respectively. The gas production constants in combination explained 84-90% of the variation of DMI. It was concluded that the accuracy of predicting DMD or DMI can be increased when gas production constants are used in combination, and the in vitro gas production technique has good potentiality to predict DMD and DMI.
(30-June-2004)
 

Komwihangilo DM, Chenyambuga SW, Lekule FP, Mtenga LA, Muhikambele VRM (2005) Comparison of indigenous browses and sunflower seed cake supplementation on intake and growth performance of dual-purpose goats fed Buffel grass (Cenchrus ciliaris) hay. Asian-Australasian Journal of Animal Sciences 18 (7): 966-972

KEYWORDS: indigenous browses, goats, intake, digestibility, growth, leucaena-leucocephala, gliricidia-sepium, napier grass, central tanzania, semiarid areas, tree legumes, sesbania, forage, diets, rumen

SUMMARY: A study to compare the effects of supplementing Delonix elata, Grewia similis, Tamarindus indica and sunflower seed cake on intake and growth rate of dual-purpose goats fed low quality Buffel grass (Cenchrus ciliaris) hay was carried out. Twenty-eight male goats aged five to seven months (mean weight 12.93 +/- 3.94 kg) were randomly allocated to four dietary groups in a completely randomised design. The diets were hay plus Grewia similis, hay plus Delonix elata, hay plus Tamarindus indica and hay plus sunflower seed cake. All diets were supplemented with maize bran. The experimental period was 90 days. Voluntary dry matter intake of the supplements was higher for Tamarindus indica (275.5 g/day) and Grewia sitnilis (201.8 g/day) and lowest for sunflower seed cake (81 g/day). Goats supplemented with Grewia similis had the highest hay intake (183.8 g/day) while those supplemented with sunflower seed cake had the lowest hay intake (98.9 g/day). Animals fed browse supplements gained significantly more weight (p < 0.001) than those with sunflower seed cake. There were no significant differences in live weight change between goats fed the different browses. However, those fed Tamarindus indica gained an average of 20.79 g/d which was slightly higher than the gains for those on Grewia similis and Delonix elata while those fed sunflower seed cake lost weight. Correspondingly, goats supplemented with browse leaf meals had higher feed conversion ratios than those supplemented with sunflower seed cake and required 23.91 to 35.06 g DM of feed to produce one g of weight gain per day In a separate study, the DM disappearance pattern indicated that Grewia similis and Delonix elata were highly degradable compared to Tamarindus indica. At 24 h of incubation, DM degradability was 627, 588 and 345 g/kg DM for Grewia similis, Delonix elata and Tamarindus indica, respectively. In another study in vivo DM digestibility ranged from 46.1% (for hay alone) to 56.2% (for hay plus Grewia similis). It was concluded that the addition of Tamarindus indica, Grewia similis and Delonix elata leaf meals to Cenchrus ciliaris hay resulted in increased total DM intake, in vivo digestibility and growth rate. Therefore, leaf meals of indigenous browses particularly Tamarindus indica and Grewia similis could be used as supplementary feeds for small ruminants grazing on poor quality roughages during the dry season rather than use of expensive, less effective and intermittently available sunflower seed cake.
(30-June-2004)
  

Ure AL, Dhiman TR, Stern MD, Olson KC (2005) Treated extruded soybean meal as a source of fat and protein for dairy cows. Asian-Australasian Journal of Animal Sciences 18 (7): 980-989

KEYWORDS: cow, soybean meal, extrusion, milk, fat, protein, ruminal fermentation, early lactation, dietary-fat, milk-fat, performance, rumen, supplementation, metabolism, digestion, urea

SUMMARY: The influence of treated, extruded, partially expelled soybean meals as undegradable protein and bypass fat sources on lactation performance and ruminal fermentation of dairy cows was studied. Experiment 1: nine cows were used in a replicated 3x3 Latin square design with each period being 3 wk in duration. Cows were fed 440 g/kg forage and 560 g/kg grain diet with one of three extruded soybean meals fed at 110 g/kg of the diet. The 3 soybean meals were 1) twice-extruded soybean meal (ESM; as a control); 2) lignosulfonate-treated, twice-extruded soybean meal (LSM); and 3) calcium oxide plus lignosulfonate-treated, twice extruded soybean meal (CLSM). Experiment 2: 3 ruminally cannulated cows were used in a 3x3 Latin square to stud the treatment influence on ruminal fermentation characteristics. Feeding treated soybean meal to cows in LSM and CLSM treatments did not improve feed intake, milk yield, or milk composition except that cows fed the LSM and CLSM treatments produced less milk protein compared with the ESM treatment. The proportion of C-18:2 was greater in milk fat of cows fed CLSM compared with that of cows fed the ESM or LSM treatments. Ruminal pH, ammonia, and total volatile fatty acids were not affected by treatment. An increased proportion of C-18:2 in milk fat suggests that there is a potential use of calcium salts of fatty acids in protecting the lipid portion of extruded soybean meal and further research is needed to explore this potential with full-fat extruded soybeans not with extruded and partially oil expelled soybeans.
(30-June-2004)

Srinivas B, Krishnamoorthy U (2005) Influence of diet induced changes in rumen microbial characteristics on gas production kinetics of straw substrates in vitro. Asian-Australasian Journal of Animal Sciences 18 (7): 990-996

KEYWORDS: rumen microbes, gas production, tracer techniques, straw, fermentation, urea, cattle, energy, performance, supplements, quality, invitro, calves, acid

SUMMARY: The effect of diets varying in level and source of nitrogen (N) and fermentable organic matter on dynamic characteristics of microbial populations in rumen liquor and their impact on substrate fermentation in vitro was studied. The diets tested were straw alone, straw+concentrate mixture and straw+urea molasses mineral block (UMMB) lick. The same diets were taken as substrates and tested on each inoculum collected from the diets. Diet had no effect on the amino acid (AA) composition of either bacteria or protozoa. Differences among the diets in intake, source of N and OM affected bacterial and protozoal characteristics in the rumen. Upper asymptote of gas production (Y alpha) had a higher correlation with bacterial pool size and production rate than with protozoal pool size and production rate. Among the parameters of the gas production model, Y alpha and lag time in total gas has showed significant (p < 0.01) correlation with bacterial characteristics. Though the rate constant of gas production significantly differed (p < 0.01) between diet and type of straw, it was least influenced by the microbial characteristics. The regression coefficient of diet and type of straw for Y alpha indicated that the effect of diet on Y alpha was threefold higher than that of the straw. As microbial characteristics showed higher correlation with Y alpha, and diet had more influence on the microbial characteristics, gas production on a straw diet could be used effectively to understand the microbial characteristics.
(30-June-2004)
 

Tafaj M, Kolaneci V, Junck B, Maulbetsch A, Steingass H, Drochner W (2005) Influence of fiber content and concentrate level on chewing activity, ruminal digestion, digesta passage rate and nutrient digestibility in dairy cows in late lactation. Asian-Australasian Journal of Animal Sciences 18 (8): 1116-1124

KEYWORDS: dairy cows, chewing activity, rumen digestion, passage rate, hay/concentrate-ratio, particle-size, cattle, rumen, fermentation, sheep, fermentability, requirements, ingestion, feed, diet

SUMMARY: The influence of fiber content of hay (low-fiber 47% NDF and high-fiber 62% NDF of DM) and concentrate level (high 50% and low 20% of ration DM) on chewing activity, passage rate and nutrient digestibility were tested on four restrict-fed (11.1 to 13.7 kg DM/d) Holstein cows in late lactation. Aspects of ruminal fermentation and digesta particle size distribution were also investigated on two. ruminally cannulated (100 mm i.d.) cows of the same group of animals. All digestion parameters studied were more affected by the fiber content of the hay and its ratio to non structural carbohydrates than by the concentrate level. Giving a diet of high fiber (62% NDF) hay and low concentrate level (20%) increased chewing activity but decreased solid passage rate and total digestibility of nutrients due to a limited availability of fermentable OM in the late cut fiber rich hay. A supplementation of high-fiber hay with 50% concentrate in the diet seems to improve the ruminal digestion of cell contents, whilst a depression of the ruminal fiber digestibility was not completely avoided. Giving a diet of low-fiber (47% NDF) hay and high concentrate level (50%) reduced markedly the chewing and rumination activity, affected negatively the rumen conditions and, consequently, the ruminal digestion of fiber. A reduction of the concentrate level from 50 to 20% in the diet of low-fiber hay improved the rumen conditions as reflected by an increase of the ruminal solid passage rate and of fiber digestibility and in a decrease of the concentration of large particles and of the mean particle size of the rumen digesta and of the faeces. Generally, it can be summarised that, (i) concentrate supplementation is not a strategy to overcome limitations of low quality (fiber-rich) hay, and (ii) increase of the roughage quality is an effective strategy in ruminant nutrition, especially when concentrate availability for ruminants is limited.
(30-June-2004)
   

Takahashi J, Mwenya B, Santoso B, Sar C, Umetsu K, Kishimoto T, Nishizaki K, Kimura K, Hamamoto O (2005) Mitigation of methane emission and energy recycling in animal agricultural systems. Asian-Australasian Journal of Animal Sciences 18 (8): 1199-1208

KEYWORDS: methane, Yucca schidigera, Quillaja saponarea, oligosaccharide, fuel cell, biogas plant, ruminal fermentation, yeast culture, galacto-oligosaccharides, yucca-schidigera, sulfur-compounds, l-cysteine, in-vitro, nitrate, sheep, rumen

SUMMARY: Abatement of greenhouse gas emitted from ruminants and promotion of biogas energy from animal effluent were comprehensively examined in each anaerobic fermentation reactor and animal experiments. Moreover, the energy conversion efficiency of biomass energy to power generation were evaluated with a gas engine generator or proton exchange membrane fuel cell (PEMFC). To mitigate safely rumen methanogenesis with nutritional manipulation the suppressing effects of some strains of lactic acid bacteria and yeast, bacteriocin, beta 1-4 galactooligosaccharide, plant extracts (Yucca schidigera and Quillaja saponarea), L-cysteine and/or nitrate on rumen methane emission were compared with antibiotics. For in vitro trials, cumulative methane production was evaluated using the continuous fermented gas qualification system inoculated with the strained rumen fluid from rumen fistulated Holstein cows. For in vivo, four sequential ventilated head cages equipped with a fully automated gas analyzing system were used to examine the manipulating effects of beta 1-4 galactooligosaccharide, lactic acid bacteria (Leuconostoc mesenteroides subsp. mesenteroides), yeast (Trichosporon serticeum), nisin and Yucca schidigera and/or nitrate on rumen methanogenesis. Furthermore, biogas energy recycled from animal effluent was evaluated with anaerobic bioreactors. Utilization of recycled energy as fuel for a co-generator and fuel cell was tested in the thermophilic biogas plant system. From the results of in vitro and in vivo trials, nitrate was shown to be a strong methane suppressor, although nitrate per se is hazardous. L-cysteine could remove this risk. beta 1-4 galactooligosaccharide, Candida kefyr nisin, Yucca schidigera and Quillaja saponarea are thought to possibly control methanogenesis in the rumen. It is possible to simulate the available energy recycled through animal effluent from feed energy resources by making total energy balance sheets of the process from feed energy to recycled energy.
(30-June-2004)
 

Ramirez-Restrepo CA, Barry TN (2005) Alternative temperate forages containing secondary compounds for improving sustainable productivity in grazing ruminants. Animal Feed Science and Technology 120 (3-4): 179-201

KEYWORDS: forages, chicory, Lotus corniculatus, perennial ryegrass/white clover pasture, parasite control, reproduction, secondary compounds, sulla, bloat safe, methane reduction, sulla hedysarum-coronarium, lucerne medicago-sativa, perennial ryegrass/white clover, chicory cichorium-intybus, condensed tannins, lotus-corniculatus, wool production, gastrointestinal nematodes, reproductive efficiency, fecal egg

SUMMARY: The use of alternative temperate forages to improve the sustainable productivity of grazing ruminants, relative to grass-based pastures, is reviewed. Particular emphasis is placed upon forages containing secondary compounds for sustainable control of internal parasites, for increasing reproductive rate in sheep, reducing bloat risk in cattle and for reducing methane production as a means of lowering greenhouse gas emissions.
Of the forages reviewed, the herb chicory (Chicorium intybus) and the condensed tannin-containing legumes Lotus comiculatus L. and sulla (Hedysarum coronarium) offered the most advantages. Chicory and sulla promoted faster growth rates in young sheep and deer in the presence of internal parasites, and showed reduced methane production in other studies. L. corniculatus was not as effective as chicory and sulla in promoting growth of lambs in the presence of internal parasites. Grazing on L. corniculatus was associated with increases in reproductive rate in sheep, increases in milk production in both ewes and dairy cows and reduced methane production, effects that were mainly due to its content of condensed tannins (CT). Grazing ewes on L. corniculatus during mating and very early pregnancy may also reduce lamb mortality. However, there are no data on the effect of mating ewes, which are grazing chicory on their reproductive performance, an important omission. Risk of rumen frothy bloat in cattle grazing legumes is reduced when the forage contains 5 g CT/kg dry matter (DM) or greater. Gene transfer techniques aimed at achieving this for lucerne (Medicago sativa) have made progress, but CT concentration needs to be further increased from calculated values of 0.75-1.25 g CT/kg DM in the transformed plants. Bloat control may be achievable in genetically transformed legumes before increased amino acid absorption, as the concentration of CT required for bloat control is lower (5 versus 30-40 g/kg DM) than that required to cause increased amino acid absorption and is not affected by differences in CT structure.
Key plant characteristics for improved sustainable productivity are a high ratio of readily fermentable: structural carbohydrate and the presence of CT and certain other secondary compounds. Taking into account both nutritional and agronomic considerations, chicory is considered one of the best emerging plants for grazing livestock, with L. corniculatus being more suitable for areas with dry summers and warm winters. Some of the agronomic limitations of L. corniculatus and sulla could be reduced by mechanical harvesting and their inclusion as a component in total mixed rations (TMR), instead of grazing.
(30-June-2004)
 

Engels FM, Jung HJG (2005) Alfalfa stem tissues: Impact of lignification and cell length on ruminal degradation of large particles. Animal Feed Science and Technology 120 (3-4): 309-321

KEYWORDS: alfalfa, Medicago sativa, stem tissues, depth of degradation, cell length, lignitication, degradability, breakdown

SUMMARY: A series of experiments were conducted with alfalfa to determine how extensively rumen microorganisms can degrade various tissues within large stem pieces. The seventh internode from the base of the stem was collected from alfalfa clone 718 after 4 weeks of regrowth. Internode length and diameter were measured, and approximately 2 cm stem pieces were excised from the internodes. Stem pieces were incubated with rumen fluid in vitro for 24 h. Bee's wax was used to coat the stem pieces to prevent microbial access other than at one end of the stem pieces. After exposure to the rumen microorganisms, stem pieces were serially cross-sectioned starting at the exposed surface. Sections were examined by light microscopy to determine which tissues had been degraded and to what depth into the stem piece degradation had occurred. Non-lignified alfalfa stem tissues (chlorenchyma, collenchyma, cambium, and primary xylem parenchyma) were degraded to great depth in stem pieces, but degradation of lignified tissues (phloem fibres and xylem fibres) was much more limited. Depth of degradation was greater in stem pieces derived from long internodes compared to short internodes. Using longitudinal sections and isolated cells of stem tissues, it was found that mean cell length increased by approximately 50% with a doubling of internode length for all tissues examined. Many cell layers of non-lignified tissues were degraded whereas only the exposed cell layer of lignified tissues exposed at the cut end of the internode pieces was susceptible to degradation. Depth of degradation for non-lignified tissues was attributed to a combination of cell wall degradability, cell length, and the presence of intercellular spaces in chlorenchyma tissue. The lignitied wall established a complete barrier to degradation of cells below those mechanically ruptured.
(30-June-2004)
 

Hu WL, Liu JX, Ye JA, Wu YM, Guo YQ (2005) Effect of tea saponin on rumen fermentation in vitro. Animal Feed Science and Technology 120 (3-4): 333-339

KEYWORDS: tea saponin, ruminal fermentation, methane, in vitro, yucca-schidigera extract, ruminal fermentation, steroidal saponins, protein-synthesis

SUMMARY: The present study was conducted to investigate the effect of tea saponins (TS) on ruminal fermentation in vitro using gas syringes as incubators. The TS were added at levels of 0, 2,4, 6 and 8 mg against 200 mg mixture of corn meal and grass meal (1/1, w/w) in rumen fluid. In vitro gas production (GP) was recorded and methane concentration was determined at 3, 6, 9, 12 and 24 h incubation. After 24 h, the incubation was stopped and the inoculants were determined for pH, ammonia-N, volatile fatty acids (VFAs), protozoa counts and microbial protein yield. The GP was increased with the increasing level of TS except 8 mg at 24 h, which kept little change from that of the control. Methane concentration was decreased at all levels of TS at each incubation time. At 24 h incubation, inclusion with 2, 4, 6 and 8 mg of TS decreased methane concentration by 13, 22, 25 and 26%, respectively. The pH of ruminal fluid was slightly lower at 4 and 6 mg TS, but all values were in the normal range. Ammonia-N concentrations decreased significantly (P < 0.01) when the TS were included. Concentrations of individual and total VFAs were not significantly effected by TS addition. The TS significantly inhibited the protozoa growth in ruminal fluid (P < 0.01). At 24 h incubation, protozoa counts were reduced by 19, 25, 45 and 79%, respectively at levels of 2, 4, 6 and 8 mg of TS compared to that in control. The microbial protein was enhanced with the TS addition except 2 mg level, and reached 1.92, 2.36 and 2.61 mg/mL with addition of 4, 6 and 8 mg TS, compared to 1.50 mg/mL in control. It is suggested that TS could modify the rumen fermentation and inhibit the release of methane and ammonia, which may be beneficial for improving nutrient utilization and animal growth.
(30-June-2004)
 

Wang JH, Zhu BW, Song MK, Choic YJ (2005) Effect of monensin, fish oil or their combination on in vitro fermentation and conjugated linoleic acid (CLA) production by ruminal bacteria. Animal Feed Science and Technology 120 (3-4): 341-349

KEYWORDS: CLA, monensin, fish oil, in vitro, ruminal bacteria, fatty-acids, octadecenoic acid, rumen bacteria, trans-11 CLA, biohydrogenation, plasma, milk, cows, concentrate, oilseeds

SUMMARY: An in vitro study was conducted to examine the effect of adding monensin, fish oil, or their combination on rumen fermentation and conjugated linoleic acid (CLA) production by mixed ruminal bacteria when incubated with safflower oil. Concentrate (1 g/100 ml) with safflower oil (0.2 g/100 ml) was added to a mixed solution (600 ml) of strained rumen fluid and buffer (control). Monensin (10 ppm), fish oil (0.02 g/100 ml), or monensin plus fish oil was also added into control mixture. All the culture solutions prepared were incubated anaerobically at 39 degrees C for 12 h. A higher pH and ammonia concentration were observed from the culture solution containing monensin at 12 h of incubation than those from the control or the culture containing fish oil. Monensin increased (P < 0.007) the C-3 content over all the collection times of culture solution while reducing the C-4 content at 6 h (P < 0.018) and 12 h (P < 0.001) of incubations. Supplementation of monensin, fish oil or their combination changed the content of C-18-fatty acids of ruminal culture. Monensin alone reduced (P < 0.02 1) the content of cis-9, trans-11 CLA compared to fish oil at all sampling times, but increased (P < 0.041) the trans-10, cis-12 CLA production compared to fish oil addition and the control which were similar at incubation for 12 h. The combination of monensin and fish oil increased the content of cis-9, trans-11CLA (P < 0.023) and transvaccenic acid (TVA, P < 0.018) significantly compared to the control or monensin alone at incubation for 12 h.
(30-June-2004)
 

An DD, Dong XZ, Dong ZY (2005) Prokaryote diversity in the rumen of yak (Bos grunniens) and Jinnan cattle (Bos taurus) estimated by 16S rDNA homology analyses. Anaerobe 11 (4): 207-215

KEYWORDS: prokaryote diversity, 16S rDNA homology, yak, cattle, rumen, phylogenetic analysis, bacterial community, sequence-analysis, methanogens, libraries

SUMMARY: Prokaryote diversity in the rumen of yak (Bos grunniens) and Jinnan cattle (Bos taurus) was estimated by 16S rDNA homology analysis. Two rumen 16S rDNA libraries were constructed. Of the 194 clones in the library of yak rumen, the sequences were mainly clustered to two phyla, low G + C Gram-positive bacteria (LGCGPB, 54.12% total clones) and Bacteroidetes (30.93%), respectively. While in the 197 clone-library of the cattle rumen, the sequences were mainly related to three phyla, Bacteroidetes (39.59%), gamma-Proteobacteria (26.9%) and LGCGPB (22.34%), respectively. The sequence analysis indicated that more than half of the species harbored in yak rumen belonged to the not-yet-cultured groups at <90% 16S rDNA similarity levels with cultured species, while 36% 16S rDNA sequences amplified from the rumen of Jinnan cattle fell in these catalogues. By comparing the uncultured sequences in yak rumen with those in Jinnan cattle and cow, the former formed distinct clusters loosely related to the later, implying that yak rumen could harbor some special prokaryote phyla. 10.8% sequences retrieved in yak rumen were related to the known rumen fibrolytic bacterial species; however none was related to the known amylolysis species., while 4% and 17.8% sequences retrieved from Jinnan cattle rumen were related to cultured fibrolytic and amylolysis species, respectively. The bacterial structures seemed to be in accordance with the feed of the two kinds of animals. In both rumens, retrieved methanogenic Archaea-related 16S rDNA sequences were at an unreasonable low level; in addition, none sequence was related to Ruminococcus albus, a classical rumen fibrolytic species. The reason can be due to the experimental biases.
(30-June-2004)
 

Muturi KN, Scaife JR, Lomax MA, Jackson F, Huntley J, Coop RL (2005) The effect of dietary polyunsaturated fatty acids (PUFA) on infection with the nematodes Ostertagia ostertagi and Cooperia oncophora in calves. Veterinary Parasitology 129 (3-4): 273-283

KEYWORDS: PUFA, eosinophils, mucosal mast cells, worm counts, Ostertagia ostertagi, Cooperia oncophora, mucosal mast-cells, lymphocyte functions, gastrointestinal nematodes, prostaglandin e-2, immune rats, sheep, circumcincta, eosinophils, resistance, ruminants

SUMMARY: Diet-induced changes in the polyunsaturated fatty acid (PUFA) content of immune cells influences the immune phenotype that develops following infection. The aim of this study was to examine the effect of manipulating dietary PUFA supply on tissue fatty acids composition and immunity to a mixed infection with an abomasal and an intestinal nematode parasite in calves. Calves (n = 24) were allocated into two treatment groups and fed 25 g/day of either fish oil (n-3 group) or a binary mixture of palm/rapeseed oil (normal group) as a supplement in milk replacer. Within each treatment group eight calves were infected with 2000 L3 Ostertagia ostertagi and Cooperia oncophora, three times per week for 8 weeks, the remaining calves were pair-fed uninfected controls. Faecal egg counts (FEC) were carried out twice weekly. At slaughter, the whole gut was removed intact for worm counts and tissue samples were taken for fatty acid analysis. Samples of abomasum, duodenum and mid-gut were also collected for immunohistological analysis. FEC were not significantly influenced by oil supplement but tended to remain higher in the palm/rapeseed oil-fed group (normal infected). The number of intestinal immature worms was significantly (p < 0.05) higher in the n-3 group. Mucosal mast cell (MMC) and eosinophil numbers were significantly increased (p < 0.05) by infection and were significantly lower (p < 0.05) in the intestinal tissue of the fish oil supplemented and infected group (n-3 infected group). These results suggest that feeding an n-3 PUFA-rich supplement (fish oil) can influence cellular mediators of immunity to nematode infection. This is the first report of the establishment of patency and the subsequent development of immunity to a mixed infection with O. ostertagi and C. oncophora in calves undergoing early rumen development. The trend in the FEC, MMC and eosinophil numbers in the n-3 group suggests that decreasing the dietary n-6/n-3 PUFA ratio may be a worthwhile immunonutritional strategy for potentiating the immune response to nematode parasite infection in the calf.
(30-June-2004)
 

Yu P (2005) Potential protein degradation balance and total metabolizable protein supply to dairy cows from heat-treated faba beans. Journal of the Science of Food and Agriculture 85 (8): 1268-1274

KEYWORDS: faba bean, protein degradation balance, metabolizable protein, NRC 2001 model, starch, rumen

SUMMARY: The effects of pressure toasting (100, 118 and 136 degrees C for 3, 7, 15 and 30 min) on potential protein nutritional value of faba beans were evaluated with the NRC 2001 dairy model, by determining undegraded (RUP) and degraded rumen protein (RDP), undegraded (RUST) and degraded rumen starch (RDST), truly absorbed undegraded protein (ARUP), microbial protein (MCPRDP) synthesized in the rumen from rumen-available protein, truly absorbed rumen synthesized microbial protein (AMCP), truly absorbed rumen endogenous protein (AECP), total metabolizable protein (MP) in the small intestine, and the protein degradation balance (PDB). The treatments increased RUP, RUST, ARUP and MP (p < 0.001), and decreased RDP, RDST, MCPRDP and PDB (p < 0.001), the effects increasing with increasing temperature and time. The treatments increased (p < 0.001) ARUP without affecting AECP and AMCP, so that the net absorbable total NIP in the small intestine was increased. The PDB was reduced (p < 0.001) but never became negative. These results indicated that potential microbial protein synthesis would not be impaired due to sufficient nitrogen in the rumen, but the high positive PDB values with most treatments, except 136 degrees C for 15 min (PDB 2.0 g kg-1 DM) indicated that there were large potential losses of nitrogen in the rumen, particularly for the control with a value of 88.9 g kg-1 dry matter. It is concluded that predicted potential protein degradation balance and total metabolizable protein supply from faba beans were improved by the treatments.
(30-June-2004)
 

Martinez TF, Moyano FJ, Diaz M, Barroso FG, Alarcon FJ (2005) Use of tannic acid to protect barley meal against ruminal degradation. Journal of the Science of Food and Agriculture 85 (8): 1371-1378

KEYWORDS: by-pass starch, concentrate feeds, scanning electron microscopy, tannins, condensed tannins, rumen degradation, starch digestion, nutritive-value, lotus-pedunculatus, small-intestine, sorghum grain, bag technique, sheep, formaldehyde

SUMMARY: The inefficiency of starch utilisation by ruminants fed readily fermentable cereal grains, such as barley, decreases the metabolic potential of such feeds and can cause serious dysfunctions related to acidosis or pre-acidosis status in animals with higher energy requirements. The rate and extent of ruminal disappearance of grain dry matter (DM) are determined largely by the morphological features of the seed endosperm, but the presence of polyphenols may also constitute a limiting factor in ruminal hydrolysis. To assess the impact of tannins on the rate and extent of ruminal fermentation of barley grain, commercial grade tannic acid (TA) was included at 0, 1.0, 2.5 or 5.0% (wt/wt, DM basis) with ground barley grain in incubation in situ, and disappearance of DM and crude protein were monitored over 48 h. A dose-dependent effect of TA on in situ degradation of barley meal was observed; significance was attained (p < 0.05) at the 5% treatment level. Scanning electron microscopy revealed limited microbial hydrolysis of endosperm cell walls in TA-treated samples, although TA did not prevent microbial attachment to or hydrolysis of starch granules. Tannins may be effective for slowing ruminal disappearance of barley to improve starch utilisation by ruminants.
(30-June-2004)
 

Granzin BC (2005) Effect of timing of protein supplementation on the performance of lactating dairy cows. Australian Journal of Experimental Agriculture 45 (4): 337-345

KEYWORDS: ammonia concentration, rumen, pasture, carbohydrate, nitrogen, passage, energy

SUMMARY: Two experiments were undertaken to determine the effect of timing of protein supplementation on performance of grazing, lactating Holstein - Friesian cows fed maize silage and grain-based concentrate. In experiment 1, 36 cows were fed 0.8 kg DM/day of solvent-extracted cottonseed meal (CSM) either as 1 meal at 1200 hours with maize silage ( CSM 1200) or at 1530 hours with concentrate ( CSM 1530), or in 2 meals at 0600 and 1530 hours with concentrate ( CSM 600 + 1530).
In experiment 2, 36 cows were either fed no CSM ( control) or fed 1.0 kg DM/day as either CSM 1200 or CSM 600 + 1530. In experiment 1, daily yields of 4% fat-corrected milk (FCM) and milk fat for CSM 600 + 1530 were significantly higher than for CSM 1530 with respective means of 22.8 v. 20.7 L and 895 v. 804 g. Daily yields of FCM and milk fat for CSM 1200 were intermediate (21.7 L and 841 g/cow, respectively). A similar trend for daily protein yield per cow was noted ( 712, 695 and 666 g for CSM 600 + 1530, 1200 and 1530, respectively). In experiment 2, milk yield differed numerically between CSM 600 + 1530 and other treatments, with means ( +/- s. e. d.) of 24.7 +/- 0.78, 22.9 +/- 0.78 and 22.9 +/- 0.78 L/cow. day for CSM 600 + 1530, CSM 1200 and control, respectively. Mean ( +/- s. e. d.) net energy requirements for milk production and liveweight change tended to be lower for the control ( 68 +/- 3.6 MJ/cow. day) as opposed to CSM 600 + 1530 ( 79 +/- 3.6 MJ/cow. day) and CSM 1200 ( 76 +/- 3.6 MJ/cow. day).
Cumulative time where rumen degradable nitrogen: rumen degradable dry matter was less than 22 g/kg were 2, 2 and 3 h for CSM 600 + 1530, CSM 1200 and CSM 1530, respectively, in experiment 1, and 6, 4 and 2 h for the control, 1200 and CSM 600 + 1530, respectively, in experiment 2. No differences in rumen ammonia-N concentrations were noted between treatments in experiment 1. In experiment 2, a significantly lower mean ( +/- s. e. d.) rumen ammonia-N concentration was recorded for the control at 1530 hours ( 62 +/- 14.1 mg/dL) in comparison to CSM 600 + 1530 ( 114 +/- 14.1 mg/dL) and CSM 1200 ( 119 +/- 14.1 mg/dL).
These experiments show that for grazing dairy cows supplemented with maize silage and grain-based concentrate, feeding a daily aliquot of CSM as 2 meals at 0600 and 1530 hours rather than 1 meal at 1200 or 1530 hours improves milk production.
(30-June-2004)
 

Sahoo A, Kamra DN, Pathak NN (2005) Pre- and postweaning attributes in faunated and ciliate-free calves fed calf starter with or without fish meal. Journal of Dairy Science 88 (6): 2027-2036

KEYWORDS: rumen fermentation, calf starter, defaunation, animal protein, rumen fermentation, young calves, solid feeds, protozoa, metabolism, period, sheep, diet, age, purification
SUMMARY: In a 2 x 2 factorial design, 24 newborn, crossbred (Bos indicus x Bos taurus) calves were distributed in 4 equal groups involving dietary treatments of prestarter diets with (FM) or without fish meal (NFM) in a faunated (F) or ciliate-free (D) ruminal environment to study the ruminal fermentative development in preand postweaning periods. Defaunation was achieved by rearing calves in isolation and its effect was studied after first appearance of ciliate protozoa (observed after 8 wk of age) in the faunated animals. Calves were fed colostrum for 24 h and whole milk until weaning at 8 wk of age. Ruminal content samples were collected on d 4, 1 wk, weekly to 8 wk, and then biweekly at 9, 11, and 13 wk of age. The samples were analyzed for fermentation products [pH, total volatile fatty acids (VFA) and ammonia N] and enzyme [carboxymethyl (CM) cellulase, xylanase, beta-glucosidase, alpha-amylase, beta-galactosidase, proteases, and urease] activities. Weekly feed intake increased with age, but was similar in both groups. Ruminal pH declined steadily during 0 to 4 wk of age and then stabilized. The total VFA concentration increased with the age. The ammonia N (mg/dL) concentration increased from 14.9 on d 4 to 32.4 at 4 wk, decreased to 17.6 at 8 wk, and then steadied during the postweaning period. Samples collected on d 4 had no fibrolytic activity. Xylanase (U/dL) appeared first (1 wk) followed by beta-glucosidase (U/dL) and CM cellulase (U/dL), which increased steadily from a low of 4.69, 0.08, and 2.95 to 31.8 (6 wk), 5.92 (7 wk), and 19.8 (8 wk), respectively, and the concentrations showed nonsignificant alterations during postweaning periods. The concentration of alpha-amylase (U/dL) increased from 34.3 on d 4 to 87.2 at 8 wk, and then decreased to 56.6 (13 wk). beta-Galactosidase increased up to 6 wk then decreased to trace level (0.20 U/dL) at 13 wk of age. The concentrations of proteases and urease reached a steady state after 1 wk of age. The effect of diet type on ruminal fermentation products and enzyme parameters was nonsignificant. However, a steady and proportional alteration in both parameters in response to dry feed intake with the advancement of age was seen in all calves. Defaunation increased total VFA (97.3 vs. 75.8 mM/ L) and alpha-amylase activity (80.3 vs. 61.4 U/dL) and decreased ammonia N (16.4 vs. 21.1 mg/dL), whereas the effect on other parameters was nonsignificant. Ruminal fermentative changes responded to dry feed intake, but did not differ in response to animal protein in prestarter diet.
(30-June-2004)
 

Zheng HC, Liu JX, Yao JH, Yuan Q, Ye HW, Ye JA, Wu YM (2005) Effects of dietary sources of vegetable oils on performance of high-yielding lactating cows and conjugated linoleic acids in milk. Journal of Dairy Science 88 (6): 2037-2042

KEYWORDS: vegetable oil, milk performance, conjugated linoleic acid, lactating cow, dairy-cows, fatty-acids, rumen

SUMMARY: This study was conducted to examine the effects of dietary supplementation with vegetable oils on performance of high-yielding lactating cows and conjugated linoleic acid (CLA) content in milk fat. Twelve lactating Holstein cows in early lactation (30 to 45 d postpartum) were used in a triple 4 x 4 Latin square design. In each period, the cows in each group were fed the same basal diet and received one of the following treatments: 1) control (without oil), 2) 500 g of cottonseed oil, 3) 500 g of soybean oil, and 4) 500 g of corn oil. Each experimental period lasted for 3 wk, with the first 2 wk used for adaptation to the diet. Supplementation with vegetable oils tended to increase milk yield, with the highest milk yield in the cottonseed oil group (35.0 kg/d), compared with the control (34.4 kg/d). Milk fat percentage was decreased, but there were few effects on percentage and yield of milk protein as well as milk fat yield. The cows fed added soybean oil produced milk with the highest content of trans-11 C-18:1 (23.8 mg/g of fat), which was twice that of the control (12.6 mg/g of fat). Content of cis-9, trans-11 CLA in milk fat increased from 3.5 mg/g in the control to 6.0, 7.1, and 10.3 mg/g for the cows fed oils from cottonseed, corn, and soybean, respectively. A significant linear relationship existed between trans-11 C-18:1 and cis-9, trans-11 CLA. Supplementation with oils doubled the content of total fatty acids in blood plasma, with little difference between different vegetable oil sources. Octadecenoic acid content was significantly higher in blood plasma of animals fed added oils from cottonseed and soybean than those fed with corn oil and control. The plasma trans-11 C-18:1 content was significantly higher in the oil-added animals than in control. Supplementation of vegetable oils tended to improve milk production of lactating cows, and the CLA content in milk fat was significantly increased. Soybean oil seemed to be the optimal source to increase CLA production.
(30-June-2004)
 

Santschi DE, Berthiaume R, Matte JJ, Mustafa AF, Girard CL (2005) Fate of supplementary B-vitamins in the gastrointestinal tract of dairy cows. Journal of Dairy Science 88 (6): 2043-2054

KEYWORDS: dairy cow, B vitamins, ruminal destruction, intestinal absorption, performance liquid-chromatography, nicotinic-acid, milk-production, folic-acid, net flux, biotin, niacin, absorption, concentrate, lactation

SUMMARY: Four lactating Holstein cows equipped with ruminal, duodenal, and ileal cannulas were used in 2 studies to evaluate the disappearance of supplementary B-vitamins before and from the small intestine. The cows were fed a total mixed ration with chromic oxide in 12 daily meals. Each study consisted of a control (no vitamin supplementation) and a treatment period (with vitamin supplementation). Amounts of vitamins (mg/d) supplemented in studies 1 and 2, respectively, were: thiamin: 300 and 10; riboflavin: 1600 and 2.0; niacin: 12,000 and 600; vitamin B-6: 800 and 34; biotin: 20 and 0.02; folic acid: 2600 and 111; vitamin B-12: 500 and 0.4. In study 1, vitamins were added to the feed 5 d before and during the 4-d collection period. In study 2, vitamins were infused postruminally 1 d before and during the 4-d collection period. Substantial disappearance before the duodenal cannula was noted in study 1 (67.8% thiamin, 99.3% riboflavin, 98.5% nicotinamide, 41.0% pyridoxine, 45.2% biotin, 97.0% folic acid, and 62.9% vitamin B-12). Except for nicotinamide and folate, there was almost no disappearance of postruminally infused vitamins before the duodenal cannula (study 2), suggesting extensive ruminal destruction or use. Apparent intestinal absorption values differed greatly among vitamins, but the proportion of vitamins disappearing from the small intestine was not negatively influenced by supplementation. Except for riboflavin and niacin, absolute amounts disappearing from the small intestine were greater during the treatment than the control periods, suggesting that B-vitamin supply in dairy cows is increased by supplementation, although losses in the rumen are extensive.
(30-June-2004)
 

Sylvester JT, Karnati SKR, Yu Z, Newbold CJ, Firkins JL (2005) Evaluation of a real-time PCR assay quantifying the ruminal pool size and duodenal flow of protozoal nitrogen. Journal of Dairy Science 88 (6): 2083-2095

KEYWORDS: rumen protozoal nitrogen, real-time pcr, denaturing gradient gel electrophoresis, rrna, microbial protein-synthesis, dietary urea concentration, whole linted cottonseed, dairy-cows, bacterial fractions, forage substitute, ciliate protozoa, feed-intake, rumen, markers

SUMMARY: We have recently developed a real-time polymerase chain reaction (PCR) assay to quantify copies of the genes encoding protozoal 18S rRNA. The assay includes procedures for isolating and concentrating protozoal cells from the rumen for use as a standard to convert 18S rRNA gene copies to a biomass basis. The current objectives were to 1) determine the degree of reduction of bacterial contamination in the protozoal standard, 2) determine if protozoal standards derived from ruminal fluid are appropriate for predicting duodenal flows, and 3) evaluate the assay's determined values for protozoal N in the rumen and flowing to the duodenum compared with independent measurements. Our protozoal collection method reduced non-associated bacterial contamination by 33-fold, the contamination of which could otherwise significantly bias RNA (microbial marker) and N percentages of concentrated protozoal fractions. Based on denaturing gradient gel electrophoresis, the use of protozoal cells isolated from ruminal fluid appears appropriate for use in quantitative assays determining protozoal N flow postruminally. Using real-time PCR, protozoal N was determined to be 4.8 and 12.7% of the rumen microbial N pool and 5.9 and 11.9% of the duodenal flow of microbial N on diets containing low (16%) or high (21%) forage neutral detergent fiber, respectively, which were comparable with independent measures and expectations.
(30-June-2004)
 

Flis SA, Wattiaux MA (2005) Effects of parity and supply of rumen-degraded and undegraded protein on production and nitrogen balance in Holsteins. Journal of Dairy Science 88 (6): 2096-2106

KEYWORDS: parity, nitrogen, N balance, environment, lactating dairy-cows, milk urea nitrogen, silage-based diets, corn-silage, alfalfa silage, in-situ, rapid method, degradation, excretion, urine

SUMMARY: Eight Holstein cows (4 primiparous and 4 multiparous) were used in a replicated 4 x 4 Latin square design to determine milk production response and N balance when diets had no NRC-predicted excess of rumen-undegradable protein (RUP) or rumen-degradable protein (RDP), 10% RUP excess, 10% RDP excess, or 10% excess of both RUP and RDP. Diets were fed as a total mixed ration with (dry matter basis) 25% alfalfa silage, 25% corn silage, 19 to 21% corn grain, and varying proportions of solvent soybean meal and expeller soybean meal as primary sources of supplemental RDP and RUP, respectively. Milk yield and dry matter intake (DMI) were recorded daily, and total collection of feces and urine was completed in the last 3 d of each 21-d period. Dietary crude protein averaged 17.5 and 18.5% for the recommended and excess RDP diets, respectively, and 17.3 and 18.4% for the recommended and excess RUP diets, respectively. When cows were fed excess RUP diets in the form of expeller soybean meal, DMI and milk production increased, but the opposite was true when the diets contained excess RDP in the form of solvent soybean meal. Milk composition was not affected by RDP, RUP, or by parity, and there were no parity x RDP interactions for any of the measurements. However, apparent digestibility of neutral detergent fiber, dry matter, and N increased in multiparous cows but not in primiparous cows because of excess RUP. The increase in the yield of milk N with excess RUP was not influenced by parity, but multiparous cows retained more of the additional N apparently absorbed, whereas primiparous cows excreted the additional apparently absorbed N in the urine. Overall, the difference in urinary N due to parity (70 g/d) was about 4 times greater than the impact of dietary treatments (17 g/d). Our results suggest that multiparous cows have either a much larger urea pool or a greater demand to restore body protein mobilized earlier in lactation compared with primiparous cows. Reduction in urinary N excretion in commercial dairy herds could be obtained by separately balancing rations for first and later lactations.
(30-June-2004)
 

Eun JS, Beauchemin KA (2005) Effects of a proteolytic feed enzyme on intake, digestion, ruminal fermentation, and milk production. Journal of Dairy Science 88 (6): 2140-2153

KEYWORDS: exogenous proteolytic enzyme, forage to concentrate ratio, digestibility, dairy efficiency, fibrolytic enzymes, continuous-culture, protein-synthesis, dairy-cows, ph, allantoin, extracts, urine, diets

SUMMARY: The effects of exogenous proteolytic enzyme (EPE) on intake, digestibility, ruminal fermentation, and lactational performance were determined using 8 lactating Holstein cows in a double 4x4 Latin square experiment with a 2x 2 factorial arrangement of treatments. Diets based on barley silage and alfalfa hay as the forage sources were formulated to maintain different forage to concentrate ratios [60:40 vs. 34:66, dry matter (DM) basis]. Four dietary treatments were tested: high forage (HF) without EPE (HF-EPE), HF with EPE (HF+EPE), low forage (LF) without EPE (LF-EPE), and LF with EPE (LF+EPE). The EPE, which contained proteolytic activity but negligible fibrolytic activity, was added to the concentrate portion of the diets after pelleting at a rate of 1.25 mL/kg of DM. Adding EPE to the diet increased total tract digestibilities of DM, organic matter, N, acid detergent fiber, and neutral detergent fiber, with larger increases in digestibility observed for cows fed LF+EPE. Effects of added EPE on in vivo digestibility were consistent with improvements in gas production and degradability of the individual components of the TMR observed in vitro. Ruminal enzymic activities of xylanase and endoglucanase increased with addition of EPE to the diet, which may have accounted for improvements in fiber digestion. However, feeding EPE unexpectedly decreased feed intake of cows, which offset the benefits of improved feed digestibility. Consequently, milk yield of cows fed high or low forage diets decreased with adding EPE. Nevertheless, dairy efficiency, expressed as milk/DM intake, was highest for the LF+EPE diet. Addition of EPE to the diet increased milk fat and milk lactose percentages, but decreased milk protein percentage of cows fed a low forage diet. For cows fed high forage diets, EPE only increased milk lactose percentage. Efficiency of N use for milk production was decreased for both the high and low forage diets when EPE was added to the diet. Mean ruminal pH was lowered when EPE was added a low forage diet, likely due to the increased degradation of forage and concentrate, but there was no effect of EPE on rumen pH when cows were fed high forage diets. Profiles of VFA and microbial yield were not affected by adding EPE to the diets. Adding EPE to a total mixed ration containing alfalfa hay, barley silage, and concentrate improved nutrient digestibility in the total tract, and the response was maximized with a high concentrate diet. However, improvements in digestibility were offset by decreased feed intake, likely due to increased ruminal acidosis.
(30-June-2004)
 

Grabber JH (2005) How do lignin composition, structure, and cross-linking affect degradability? A review of cell wall model studies. Crop Science 45 (3): 820-831

KEYWORDS: cinnamyl-alcohol-dehydrogenase, beta-o-4-type quinone methide, beta-d-xylopyranoside, in-vitro, chemical-composition, down-regulation, ferulic acid, hydroxycinnamic acids, tracheary elements, fiber degradation

SUMMARY: Because of the complexity of plant cell wall biosynthesis, the mechanisms by which lignin restricts fiber degradation are poorly understood. Many aspects of grass cell wall lignification and degradation are successfully modeled by dehydrogenation polymer-cell wall (DHP-CW) complexes formed with primary walls of corn Zea mays L. This system was used to assess how variations in lignin composition, structure, and cross-linking influence the hydrolysis of cell walls by fungal enzymes. Altering the normal guaiacyl, syringyl, and p-hydroxyphenyl makeup of lignin did not influence cell wall degradability; each unit of lignin depressed cell wall degradability by two units. Plants with perturbed lignin biosynthesis often incorporate unusual precursors into lignin and one of these, coniferaldehyde, increased lignin hydrophobicity and further depressed degradability by up to 30%. In other studies, lignin formed by gradual "bulk" or rapid "end-wise" polymerization of monolignols had markedly different structures but similar effects on degradability. Reductions in cell wall cross-linking, via oxidative coupling of feruloylated xylans to lignin or nucleophilic addition of cell wall sugars to lignin quinone-methide intermediates, increased the initial hydrolysis of cell walls by up to 46% and the extent of hydrolysis by up to 28%. Overall, these studies suggest that reductions in lignin concentration, hydrophobicity, and cross-linking will improve the enzymatic hydrolysis and utilization of structural polysaccharides for nutritional and industrial purposes. In ongoing work, we are developing a DHP-CW system for dicots and are investigating how cross-linking and various acylated and unusual monolignols influence the formation of lignin and the degradation of cell walls by rumen microflora.
(30-June-2004)
 

Fiems LO, Van Caelenbergh W, Vanacker JM, De Campeneere S, Seynaeve M. (2005) Prediction of empty body composition of double-muscled beef cows. Livestock Production Science 92 (3): 249-259

KEYWORDS: body composition, energy, double muscling, Belgian Blue, cows, carcass composition, reproductive-performance, condition score, Charolais cows, mature cows, cattle, weight, energy, Holstein

SUMMARY: Twenty-four nonlactating and nonpregnant Belgian Blue double-muscled cows, with diverging parities (one to seven), body conditions and body weights (436 to 903 kg), were used to investigate empty body (EB) composition. Direct measurements of EB composition, such as water, fat, protein, ash and energy, were carried out after slaughter. EB weight (EBW) averaged 624.7 kg and consisted of 393.3 kg water, 122.3 kg protein, 84.5 kg fat and 24.6 kg ash and was characterized by an energy content of 6158 MJ. Relationships between body weight (BW), body condition score (BCS), chest girth, dressing percentage, carcass grading score, EBW, rib-cut components and EB composition were determined. Significant regression equations (P < 0.001) with a coefficient of determination (R2) of more than 0.9 were obtained between BW or BW and BCS and EB water, EB fat and EB energy. The prediction of EB ash was less accurate (R2 < 0.75). The relationship could further be improved by inclusion of carcass characteristics and rib-cut components (R2> 0.95). Energy contents of EB lipids and protein amounted to 39.3 and 23.2 MJ/kg. EB protein (197 g/kg) was higher in the present double-muscled cows than reported for non-double-muscled animals, while EB fat (126 g/kg) and EB energy (9.5 MJ/kg) were lower. One BCS unit corresponded with 26.7 kg EB fat (P < 0.001; R2 = 0.659). It can be concluded that simple live animal measurements as BW and BCS can be considered as potentially useful predictors of EB composition in double-muscled cows. Theoretical calculations based on the present observed data indicated that body reserves were lower in Belgian Blue double-muscled cows than in most other breeds. Body reserve tissue may be limited in young primiparous suckling cows so that energy restriction may be detrimental for reproductive performance.
(30-June-2004)
 

Perez-Chabela ML, Guerrero I, Gutierrez-Ruiz MC, Betancourt-Rule JM (2005) Effect of calcium chloride marination and collagen content on beef, horse, rabbit and hen meat hardness. Journal of Muscle Foods 16 (2): 141-154

KEYWORDS: postmortem tenderization, ovine carcasses, injection time, mature cows, cathepsin-b, shear force, mu-calpain, tenderness, quality, muscle

SUMMARY: Overall, meat texture is composed of two types of toughness: primary toughness, because of mechanical resistance of the myofibrillar structure, and secondary toughness, by reason of connective tissue content. Primary toughness can be reduced during aging by intrinsic and extrinsic protease activity. Secondary toughness is determined by a given amount of epimysial and perimysial connective tissue, which cannot be reduced as no collagenases are naturally present in the muscle or produced by native meat microbial populations. The objective of this work was to study primary toughness reduction in meat from four animal species, i.e., beef horse, rabbit and hen, employing M. Biceps femoris, by calpain activation with calcium chloride. Secondary toughness, expressed as hydroxyproline content, and contribution of both parameters to overall hardness were also studied. Marination with 150 mM CaCl2 increased enzymatic activity in pre-rigor meat (horse and beef), but higher concentrations (250 mM) reduced enzymatic activity increments. Although beef marination considerably increased enzymatic activity, it did not reduce hardness, probably because of high collagen content. The high hydroxyproline concentration in beef and horse caused an overall hardness. Marinated horse meat had lower collagen content and a higher enzyme activity, resulting in less hard samples. As expected, pre-rigor meats, hen and rabbit, had low hardness values for both control and treated samples. Because CaCl2 in high concentrations inhibits calpain activity, it was assumed that rabbit meat calpains were inhibited at concentrations as low as 150 mM. Therefore, calpains were active in control pre-rigor rabbit meat but were inactivated by CaCl2 addition.
(30-June-2004)
.

de Campeneere S, van Herck A, Fiems LO, de Boever JL, Chiers K, Ducatelle R, de Brabander DL (2005) Effect of dietary physical structure on animal performance and lesions in the ruminal wall and feet of Belgian Blue double-muscled bulls. Animal Science 80: 185-192 Part 2

KEYWORDS: beef bulls, double muscling, feet, roughage, rumenitis, carcass composition, beef-cattle, concentrate ratio, acidosis, system, silage, steers, level, fiber, cows

SUMMARY: The influence of the physical structure level in the diet on animal performance was investigated in 52 Belgian Blue double-muscled bulls starting from a live weight of 348 kg until slaughter at about 645 kg. Four diets with different concentrate/ maize silage ratios were offered ad libitum. The structural value (SO, developed in Belgium as a measure of physical structure in the diet for dairy cows, amounted to respectively 0.63 (HSV, high SV), 0.54 (MSV, moderate So, 0.43 (LSV; low So and 0.34 (VLSV, very low So per kg dry matter. Growth rate, food intake and food conversion were all linearly affected by the decreasing SV of the diet. Among carcass parameters only the SEUROP conformation score showed a significant effect of the SV, with the MSV group having the highest score and VLSV the lowest. No important influence of the SV on the histological damage of the ruminal papillae or on the foot lesions was found.
Based on the lower growth rate and food intake of the LSV group versus the HSV group, a SV of the diet between 0.54 and 0.43 is considered as an absolute minimum for Belgian Blue double-muscled bulls.
(30-June-2004)
 

Aharoni Y, Orlov A, Brosh A, Granit R, Kanner J (2005) Effects of soybean oil supplementation of high forage fattening diet on fatty acid profiles in lipid depots of fattening bull calves, and their levels of blood vitamin E. Animal Feed Science And Technology 119 (3-4): 191-202

KEYWORDS: beef, CLA, soybean oil, extruded soybeans, forage, FA, vitamin E, conjugated linoleic-acid, milk-fat, extruded soybeans, CLAcontent, dairy-cows, fish-meal

SUMMARY: An experiment was conducted to study effects of soybean oil supplementation of a high forage fattening diet on the composition of fatty acids (FA), including vaccenic acid (VA) and conjugated linoleic acid (CLA), in lipid depots of the meat. Eighteen Friesian bull calves were fed a common total mixed ration, supplemented with either ground maize and soybean meal (C, control treatment) for a group of six calves, or soybean meal and soybean oil (SBO treatment) for a second six calf group, or extruded full fat soybean (FFS treatment) for a third six calf group. All the diets were calculated to be iso-nitrogenous and of the same ME content, and the amounts of fat added to the two oil-supplemented diets were also equal, at 33 g/kg of diet DM. The experiment commenced when the calves were 210 +/- 3 days of age, weighing 290 +/- 6 kg and lasted for 5 months until slaughter at a live weight of 470 +/- 14 kg. Blood of the calves was sampled one week before slaughter for vitamin E determination in red blood cells. Slices of the longissimus muscle between the 12th and 13th ribs were sampled from all calves at slaughter and analysed for fatty acid composition of intra-muscular and subcutaneous fat. The CLA concentrations in the FAs in intramuscular fat were 3.4, 13.0 and 15.4 mg/g in the C, SBO and FFS treatments, respectively, and the corresponding CLA concentrations in the FAs in subcutaneous fat were 5.2, 20.3 and 26.6 mg/g, respectively. The concentrations of VA in both lipid depots were also about three times greater in the SBO and FFS treatments than in the C treatment. The response of increased CLA and VA in lipid depots of meat to oil supplementation was greater than that reported in previous studies, and the reasons for this finding are discussed. The vitamin E concentration in the blood tended to increase as a result of oil supplementation, despite the increased supplementation of poly-unsaturated fatty acids, which are sensitive to oxidation.
(30-June-2004)
 

Lailer PC, Dahiya SS, Lal D, Chauhan TR (2005) Complete feed for livestock concept, present status and future trend: A review. Indian Journal of Animal Sciences 75 (1): 84-91

KEYWORDS: buffalo, cattle, complete ration, digestibility, milk production, meat production, NDF, reproduction, total mixed ration, neutral detergent fiber, lactating dairy-cows, supplementary long hay, milk-fat depression, total mixed rations, particle-size, alfalfa silage, concentrate ratios, complete diets, ad-libitum

SUMMARY: The complete feed or total mixed ration is a quantitative mixture of all dietary ingredients to provide the specific nutrients requirement. In this system the animal have continuous free choice availability of a uniform feed mixture resulting in more uniform load on the rumen.. This product is fed as a sole source of nutrients except water. A more even intake of feed into rumen is also associated with less fluctuation in the release of ammonia, so that non-protein nitrogen may be more efficiently utilized. The density of energy increases in the ration so there is a linear increase in feed intake, milk yield, milk protein and lactose yield. Particles size in processing of complete feed diets affects the milk fat level. Diets with smaller forage particle size increase the fractional turnover rate of ruminal DM and DMI and spend lesser time in the rumen for microbial digestion, thereby decreasing digestibility, particularly fibre digestion. Since organized dairy farms are coming up in our country so complete feed concept of feeding animals is becoming increasingly popular.
(30-June-2004)
 

Leiber F, Kreuzer M, Nigg D, Wettstein HR, Scheeder MRL (2005) A study on the causes for the elevated n-3 fatty acids in cows' milk of alpine origin. Lipids 40 (2): 191-202

KEYWORDS: conjugated linoleic-acid, lactating cows, phytanic acid, dairy-cows, temperate forages, condensed tannins, vitamin-e, CLA, chain, biohydrogenation

SUMMARY: The influence of grass-only diets either from ryegrass-dominated lowland pastures (400 m above sea level) or botanically diverse alpine pastures (2000 m) on the FA profile of milk was investigated using three groups of six Brown Swiss cows each. Two groups were fed grass-only on pasture (P) or freshly harvested in barn (B), both for two experimental periods in the lowlands and, consecutively, two periods on the alp. Group C served as the control, receiving a silage-concentrate diet and permanently staying in the lowlands. Effects of vegetation stage or pasture vs. barn feeding on milk fat composition were negligible. Compared with the control, alpha-linolenic acid (18:3n-3) consumption was elevated in groups P and B (79%; P < 0.001) during the lowland periods but decreased on the alp to the level of C owing to feed intake depression and lower 1 8:3n-3 concentration in the alpine forage. Average 1 8:3n-3 contents of milk fat were higher in groups P and B than in C by 33% (P < 0.01) at low and by 96% (P < 0.001) at high altitude, indicating that 18:3n-3 levels in milk were to some extent independent of 18:3n-3 consumption. The cis-9,trans-11 CLA content in milk of grass-fed cows was higher compared with C but lower for the alpine vs. lowland periods whereas the trans-11,cis-13 isomer further increased with altitude. Long-chain n-3 FA and phytanic acid increased while arachidonic acid decreased with grass-only feeding, but none of them responded to altitude. Grass-only feeding increased milk alpha-tocopherol concentration by 86 and 134% at low and high altitude (P < 0.001), respectively. Changes in the ruminal ecosystem due to energy shortage or specific secondary plant metabolites are discussed as possible causes for the high 18:3n-3 concentrations in alpine milk.
(30-June-2004)
 

Arroquy JI, Cochran RC, Nagaraja TG, Titgemeyer EC, Johnson DE (2005) Effect of types of non-fiber carbohydrate on in vitro forage fiber digestion of low-quality grass hay. Animal Feed Science and Technology 120 (1-2): 93-106

KEYWORDS: fiber digestion, non-fiber carbohydrate, starch, sugars, fungus neocallimastix-frontalis, degradable intake protein, rumen fluid pH, beef steers, prairie hay, starch, corn, cellulolysis, cellobiose, kinetics

SUMMARY: Two in vitro experiments were conducted to study the effects of supplemental non-fiber carbohydrate (NFC) and fermentation pH on rate and extent of forage neutral detergent fiber (NDF) digestion by mixed ruminal microorganisms. A low-quality grass hay (53 g/kg CP and 761 g/kg NDF) that was finely ground served as the basal forage substrate. In Experiment 1, treatments were arranged as a 4 x 2 factorial in a randomized complete block design. The first factor consisted of supplemental NFC type: none (i.e., control, grass hay only), glucose, maltose, or soluble starch. The second factor was fermentation pH: adjusted (i.e., maintained at approximately pH 6.8) or non-adjusted (i.e., pH allowed to vary from an initial pH of 6.8 without interference). Treatments in Experiment 2 were arranged as a 4 x 2 factorial in a completely randomized design. The first factor consisted of supplemental NFC type: none (i.e., control, grass hay only), glucose, corn starch, and soluble starch. The second factor consisted of fermentation pH: adjusted or non-adjusted (the same as in Experiment 1). In both experiments NFC treatments were set such that the supplemental NFC supplied approximately 200 g/kg of the total substrate dry matter. In Experiment 1, an NFC type x pH interaction (p <, 0.01) was observed for extent of NDF digestion. The extent of NDF digestion was greater (p <, 0.01) when pH was adjusted, regardless of the NFC treatment. However, when pH was not adjusted, extent of NDF digestion was depressed (p < 0.01) for treatments receiving supplemental NFC compared with the control. Rate of NDF digestion estimated by non-linear regression did not exhibit an NFC type x pH interaction (P = 0.45). When compared with the control, rate of NDF digestion was depressed (p <, 0.01) regardless of pH treatment when supplemental NFC was provided. No significant differences were observed among the three sources of supplemental NFC with regard to either rate or extent of NDF digestion. In Experiment 2, an NFC type x pH interaction was observed (p < 0.01) for extent of NDF digestion. In this experiment, no difference was observed among treatments for the extent of fiber digestion when pH was adjusted. However, similar to Experiment 1, when pH was not adjusted the extent of NDF digestion was depressed relative to the control when supplemental NFC was provided. Overall, rate of NDF digestion calculated from non-linear regression was depressed (p < 0.01), regardless of pH treatment, in response to providing a supplemental source of NFC. However, the magnitude of depression was dependent (P = 0.02) on the type of supplemental NFC included. In conclusion, our results indicate that avoiding the pH depression associated with NFC supplementation enables the maintenance of potential extent of digestion, however, the impact on rate of fiber digestion is not overridden by alleviating pH depression and is consistent with the existence of a "carbohydrate effect" on fiber digestion.
(30-June-2004)
 

Loor JJ, Ueda K, Ferlay A, Chilliard Y, Doreau M (2005) Intestinal flow and digestibility of trans fatty acids and conjugated linoleic acids (CLA) in dairy cows fed a high-concentrate diet supplemented with fish oil, linseed oil, or sunflower oil. Animal Feed Science and Technology 119 (3-4): 203-225

KEYWORDS: oil, hydrogenation, digestion, trans fatty acids, CLA, dairy cow, lactating holstein cows, fed finishing diets, milk-fat, ruminal biohydrogenation, beef steers, octadecenoic acids, duodenal flow, blood-plasma, in-vitro, digestion

SUMMARY: Ruminal hydrogenation and duodenal flow of fatty acids were evaluated in three lactating Holstein cows fed a diet with a high concentrate: forage ratio (65:35) plus 5.0g/100g dry matter sunflower oil (SO), 5.0g/100g linseed oil (LO), or 2.5g/100g fish oil (FO). A 3 x 3 Latin square with 4-week periods was used. Grass hay was the forage. Biohydrogenation of 18:2n-6 was greater with SO (0.92 than LO (0.85), and was lowest with FO (0.75). Cows fed LO had greater 18:3n-3 hydrogenation (0.95) compared with FO or SO (84%). Biohydrogenation of 20:5n-3 (EPA) and 22:6n-3 (DHA) with FO averaged 0.92 and 0.89. Flow of total conjugated linoleic acids (CLA) was greater in cows fed SO (8.3 g/d) compared with FO (4.0 g/d). Feeding LO resulted in flow of 6.9 g total CLA/d. Percentage of cis9trans11-CLA in duodenal lipids was 0.22 g/100 g total fatty acids with SO but only 0.06 or 0.13g/100 g with FO or LO. trans10,cis12-CLA percentage was greater with SO (0.19 g/100g) than FO or LO (0.04g/100 g). Flow of total non-conjugated 18:2 isomers averaged 99.4 g/d with LO and 60.3 g/d with FO or SO. Percentage of trans11cis15-18:2, derived from 18:3n-3 hydrogenation, ranked by treatment was LO (4.70g/100g) > FO (2.70g/100g)> SO (0.86g/100g). Total trans-18:1 flow did not differ due to diets (254 g/d). trans10-18:1 percentage was greater in cows fed FO or SO (12.2 g/100g) than LO (3.1 g/100 g). trans 11-18:1 percentage averaged 10.8g/100 g across diets. Flow of 18:0 was 3.8-fold greater in cows fed SO or LO (373 g/d) than FO (96 g/d). Apparent intestinal digestibility (proportion of duodenal flow) of trans9- through trans12-18:1 was greater with FO (range 0.94-0.96) than SO (0.91-0.93), and intermediate with LO (0.92-0.95). Digestibility of cis9,trans11-CLA was greater in cows fed SO (0.85) compared with FO (0.63) or LO (0.79). trans10,cis12-CLA digestibility was greater with FO or SO (0.97) than LO (0.86). Dietary EPA and DHA from fish oil (at only 0.16 of total fatty acid intake) inhibited the reduction of trans-18:1 to 18:0 during hydrogenation of unsaturated fatty acids in the basal diet and led to marked accumulation of trans10-18:1. Intake of 18:2n-6 with FO was not associated with greater flow of trans10-18:1. The effect of FO on biohydrogenation may have been associated with a combination of factors such as greater numbers of ruminal protozoa and(or) increased isomerization of trans11-18:1 to trans10-18:1 in the rumen.
(30-June-2004)
 

Chaudhary UB, Upadhyaya RS, Singh N (2005) Effect of feeding monensin and vitamin E on rumen ciliate population in goats. Indian Journal of Animal Sciences 74 (9): 980-982

KEYWORDS: animal nutrition, ciliate protozoa, goats, holotrichs, monensin, vitamin E, protein

SUMMARY: In the present study, the effect of monensin and vitamin E alone and in combination, on the rumen ciliate population in growing Barbari goat kids was studied. Reduced values of holotrichs, entodinomorphs and total ciliates were observed in monensin fed kids. Vitamin E as a supplement proved to be protective in nature against the toxic effect of monensin on rumen protozoa. Holotrichs ciliates were found more sensitive to monensin feeding than entodinomorphs to the toxicity of monensin. Variation in the sensitivity against monensin was observed amongst different ciliate protozoa. It was concluded that feeding of monensin was detrimental for the rumen ciliate population and vitamin E as a supplement partially protected the population of ciliate.
(30-June-2004)
 

Gutierrez O, Oramas A, Cairo J (2004) Effect of the supplementation with bentonite on the protection of ruminal protein. In vitro studies. Cuban Journal of Agricultural Science 38 (3): 257-262

KEYWORDS: ruminal proteolysis, bentonite, proteinic feeds

SUMMARY: The effect of the supplementation with bentonite on the in vitro ruminal protein protection was studied using four nitrogenous feeds: meal of soybean, Leucaena leucocephala, Gliricidia sepium and urea, in a completely randomized design with factorial arrangement 3 x 4 (treatment vs time). The feeds alone (T), as well as those supplemented with natural bentonite (T1) and treated with water and heat (T2) were incubated for 8 h in studies of dynamics with three replications per treatment. The production of NH3 was the main indicator of the ruminal proteolysis. For soybean, concentrations of NH3 of 17, 11 and 6 meq/L were found at the maximum time of release for the treatments T, T1 and T2 respectively, while, for leucaena, these values were 11, 7 and 10. Gliricidia and urea showed values of maximum release at 12 and 24 h, respectively, with concentrations of NH3 of 19 and 8 meq/L and of 41, 31 and 36 in this same order. The production of ammonia nitrogen, estimated as percentage of total initial nitrogen, showed high levels of degradability of the untreated feeds, with average values of 36, 45, 70 and 100 % for soybean, leucaena, gliricidia and urea, respectively. The results denote the potentiality of the sodic bentonite as protector of the rumen protein. Thus, further studies are recommended in live animals to establish the optimum levels of bentonite inclusion, according to the type of diet and the final fermentation products.
(30-June-2004)
 

Loor JJ, Doreau M, Chardigny JM, Ollier A, Sebedio JL, Chilliard Y (2005) Effects of ruminal or duodenal supply of fish oil on milk fat secretion and profiles of trans-fatty acids and conjugated linoleic acid isomers in dairy cows fed maize silage. Animal Feed Science and Technology 119 (3-4): 227-246

KEYWORDS: fish oil, trans-fatty acids, conjugated linoleic acids, long-chain n-3 fatty acids, milk fat, performance liquid-chromatography, bovine-milk, linseed oil, extruded soybeans, blood-plasma, dietary-fat, silver-ion, supplementation, concentrate, yield

SUMMARY: Milk fat secretion and profiles of conjugated linoleic acids (CLA) and trans-18:1 isomers in milk fat due to a ruminal or duodenal supply of fish oil (FO, EPA = 22% of total fatty acids, DHA = 7%) were evaluated using six lactating Holstein cows with cannulas in their rumen and duodenum. Cows were fed a control diet based on corn silage (66% of DM), or the control plus 300 mL FO/d into the rumen (FO-R) or duodenum (FO-D) for 4 weeks in a replicated 3 x 3 Latin square design. Dry matter intake was higher with the control (19.8 kg/d), intermediate with FO-D (18.0 kg/d), and lower with FO-R (16.2 kg/d). Yield of milk (22.7 kg/d), lactose (1.09 kg/d), or crude protein (0.70 kg/d) was not affected by treatments. Content of crude protein, true protein, and casein was lower in response to FO-R compared with the control. Despite similar jugular concentration compared with the control, jugular-mammary venous difference for beta-OH-butyrate was 54% lower with FO-R or FO-D. Milk fat content and yield were lowest with FO-R (25 g/kg, 567 g/d) compared with FO-D (32 g/kg, 737 g/d) or the control (35 g/kg, 783 g/d). Percentage of trans5-, trans6+7+8-, trans9-, trans 10-, trans11-,transl2-, and trans13+14-18:1 in milk fat was greater due to FO-R (0.05, 0.44, 0.48, 1.8, 9.2, 0.70, and 0.82%, respectively) compared with the control or FO-D (0.02, 0.22, 0.19, 0.27, 1.1, 0.35, and 0.40%). Although 18:0 and cis9-18:1 percentage was markedly lower in response to FO-R, percentage of cis11-, cis13-, and cis15-18:1 was greater compared with the control or FO-D. Cis9,trans11-CLA (87-95% of total CLA) averaged 3.2% in response to FO-R compared with 0.51% for control or FO-D. Trans10,cis12-18:2 was not detected. Among non-conjugated 18:2 isomers, cis9,cis12-18:2 was lower but cis9,trans13-, trans9,cis12-, and trans11,cis15-18:2 greater when FO-R was compared with the control or FO-D. There was high correlation (r = 0.94-0.99) among data obtained by GLC versus HPLC for most trans-18:1 isomers and cis9,trans11-18:2, suggesting GLC alone with our chromatographic conditions provided adequate separation of isomers. Milk 20:5n-3 (EPA) and 22:6n-3 (DHA) were 0.08 and 0.04% with the control, increased to 0.36 and 0.17% with FO-R, and were 1.47 and 0.47% with FO-D. Data indicate, ruminal supply of FO led to hydrogenation of EPA and DHA and enhanced percentage of various trans-18: 1, cis-18:1, non-conjugated 18:2, and cis9,trans11-18:2 in milk fat. Combined increases in trans-18:1 along with reduced availability of 18:0 for endogenous synthesis of cis9-18:1 may play a key role in reduced milk fat synthesis in cows fed fish oil.
(30-June-2004)
 

Ozutsumi Y, Tajima K, Takenaka A, Itabashi H (2005) The effect of protozoa on the composition of rumen bacteria in cattle using 16S rRNA gene clone libraries. Bioscience Biotechnology and Biochemistry 69 (3): 499-506

KEYWORDS: rumen, protozoa, cattle, 16s rrna gene, phylogenetic analysis, sequence-analysis, rdna libraries, population

SUMMARY: The effect of the presence of protozoa on the composition of rumen bacteria was investigated in cattle. Seven castrated Holstein cattle were divided into two groups: four faunated and three unfaunated, and 16S ribosomal RNA gene (rDNA) clonal libraries were constructed. A total of 312 clones were sequenced across 1,500 bp. The 151 sequences of the faunated cattle were classified into 98 operational taxonomic units (OTUs) having at least 97% similarity. The sequences derived from the faunated cattle were classified into Firmicates (59.7%), Bacteroidetes (34.4%), Spirochaetes (2.6%), Actinobacteria (2.0%), and Proteobacteria (1.3%). Bacteroides and Prevotella (34.4%) were the major groups in the faunated cattle. The 161 sequences in the unfaunated cattle were classified into 72 OTUs. The sequences derived from the unfaunated libraries were classified into Firmicutes (65.7%), Bacteroidetes (31.1%), Proteobacteria (1.9%), and Spirochaetes (1.2%). The Clostridium botulinum group and its relatives (36.0%) were the major groups in the unfaunated cattle. An analysis by the computer program LIBSHUFF clarified that the presence of ruminal protozoa markedly affected the composition of rumen bacteria.
(30-June-2004)
 

Petit HV, Ivan M, Mir PS (2005) Effects of flaxseed on protein requirements and N excretion of dairy cows fed diets with two protein concentrations. Journal of Dairy Science 88 (5): 1755-1764

KEYWORDS: dairy cow, flaxseed, protein, milk production, conjugated linoleic-acid, milk-production, sunflower seed, fatty-acids, protozoa population, blood composition, ciliate protozoa, early lactation, rumen protozoa, soybean-meal

SUMMARY: Thirty-eight midlactating Holstein cows averaging 597 kg of body weight (SD = 59) were used to determine the effects of dietary flaxseed on protein requirement and N excretion in urine and feces. Milk yield and composition, intake, and digestibility were also determined. Cows were allotted from wk 20 to 30 of lactation to 1 of 4 TMR containing 1) no flaxseed ( control) and 16% protein (MPC), 2) whole flaxseed and 16% protein (MPF), 3) no flaxseed ( control) and 18% protein (HPC), and 4) whole flaxseed and 18% protein (HPF). Cows fed high protein diets had greater feed intake than those fed medium protein diets (20.2 vs. 18.4 kg/d), and cows fed no flaxseed had greater dry matter intake than those fed flaxseed ( 20.1 vs. 18.5 kg/d). Milk yield was lower for cows fed MPF (20.3 kg/d) than for those fed HPC (24.4 kg/d), HPF (24.9 kg/d), or MPC (24.0 kg/d). Milk protein and lactose concentrations were similar for cows fed MPC and HPC, but flaxseed decreased milk protein concentration in cows fed MPF or HPF compared with cows fed the control diets. Milk fat concentration was similar in cows fed diets with or without flaxseed, but it was decreased by higher protein concentration. Digestibility was generally reduced when diets contained flaxseed and lower protein concentration. Dietary protein had no effect while dietary flaxseed increased fecal N excretion. Retention of N was lower in cows fed flaxseed compared with cows fed the control diets. Feeding flaxseed decreased milk concentrations of short- and medium-chain fatty acids and increased those of long-chain fatty acids. Flaxseed had no effect on the dietary requirement of N by midlactating dairy cows.
(30-June-2004)
 

de Veth MJ, Gulati SK, Luchini ND, Bauman DE (2005) Comparison of calcium salts and formaldehyde-protected conjugated linoleic acid in inducing milk fat depression. Journal of Dairy Science 88 (5): 1685-1693

KEYWORDS: conjugated linoleic acid, milk fat, milk fat depression, rumen protection,
lactating dairy-cows, dietary supplementation, holstein cows, transition period, fish-oil, cla, biohydrogenation, rumen, digestibility, ruminants

SUMMARY: Abomasal infusion studies have shown that trans-10, cis-12 conjugated linoleic acid (CLA) decreases milk fat synthesis. However, supplements of CLA must avoid rumen biohydrogenation for this technology to be applied to ruminants. Rumen protection methods would reduce CLA metabolism in the rumen and increase its supply to the small intestine. Our objective was to compare the efficacy of 2 forms of rumen-protected CLA at inducing milk fat depression. Three mid to late lactation Holstein cows each fitted with a rumen fistula were used in a 3 x 3 Latin square design. Treatments were: 1) control, 2) calcium salts of CLA (Ca-CLA), and 3) formaldehyde-protected CLA (FP-CLA). Supplements were designed to provide 10 g/d of trans-10, cis-12 CLA and were administered intraruminally once per day to ensure exact delivery of amount. Both CLA treatments substantially reduced milk fat yield and content compared with control, with the reductions in milk fat yield averaging 34% for the Ca-CLA treatment and 44% for the FP-CLA treatment. In contrast, milk yield, milk protein yield, and dry matter intake were unaltered by CLA treatment. Efficiency of transfer of trans-10, cis-12 CLA from the supplement into milk fat was 3.2 and 7.0% for Ca-CLA and FP-CLA, respectively. These values are much lower than transfer efficiencies reported for abomasally infused CLA, suggesting that much of the trans-10, cis-12 CLA present in the 2 formulations was biohydrogenated in the rumen. Overall, the extent of the reduction in milk fat yield indicates that both protection formulations are acceptable methods for the formulation of CLA supplements to induce milk fat depression in lactating dairy cows.
(30-June-2004)
 

Wallace RJ (2005) Antimicrobial properties of plant secondary metabolites. Proceedings of the Nutrition Society 63 (4): 621-629

KEYWORDS: essential oils, manipulation, ruminants, saponins, yucca-schidigera extract, high-energy diets, essential oils, rumen fermentation, ruminal microorganisms, nutrient digestion, protein-metabolism, ciliate protozoa, alfalfa saponins, de-faunation

SUMMARY: Increasing awareness of hazards associated with the use of antibiotic and chemical feed additives has accelerated investigations into plants and their extracts as feed additives. The present review mainly discusses two classes of plant secondary compounds in this context, i.e. essential oils and saponins. The broader potential of plants and their extracts is illustrated by the progress of an EC Framework 5 project, 'Rumen-up'. Dietary inclusion of a commercial blend of essential oils causes markedly decreased NH3 production from amino acids in rumen fluid taken from sheep and cattle. This effect is mediated partly by the effects on hyper-NH3-producing bacteria and the protein- and starch-fermenting rumen bacterium, Ruminobacter amylophilus. Saponin-containing plants and their extracts suppress the bacteriolytic activity of rumen ciliate protozoa and thereby enhance total microbial protein flow from the rumen. The effects of some saponins are transient, because saponins are hydrolysed by bacteria to their corresponding sapogenin aglycones, which are much less toxic to protozoa. Saponins also have selective antibacterial effects that may prove useful in, for example, controlling starch digestion. The 'Rumen-up' project began with a targetted collection of European plants and their extracts, which partners have tested for their effects on rumen proteolysis, protozoa, methanogenesis and lactate production. A success rate of about 5% in terms of positive hits illustrates that plant secondary compounds, of which essential oils and saponins comprise a small proportion, have great potential as 'natural' manipulators of rumen fermentation to benefit the farmer and the environment in the future.
(30-June-2005)
 

Shingfield KJ, Reynolds CK, Lupoli B, Toivonen V, Yurawecz MP, Delmonte P, Griinari JM, Grandison AS, Beever DE (2005) Effect of forage type and proportion of concentrate in the diet on milk fatty acid composition in cows given sunflower oil and fish oil. Animal Science 80: 225-238 Part 2

KEYWORDS: linoleic acid, milk fat, polyenoic fatty acids, trans fatty acids, conjugated linoleic-acid, lactating dairy-cows, trans octadecenoic acid, bovine-milk, duodenal flow, microbial biohydrogenation, holstein cows, cla isomers, sheep rumen, linseed oil

SUMMARY: Based on the potential benefits of cis-9, trans- 11 conjugated linoleic acid (CLA) for human health there is a need to develop effective strategies for enhancing milk fat CLA concentrations. In this experiment, the effect of forage type and level of concentrate in the diet on milk fatty acid composition was examined in cows given a mixture of fish oil and sunflower oil. Four late lactation Holstein-British Friesian cows were used in a 4 x 4 Latin-square experiment with a 2 x 2 factorial arrangement of treatments and 21-day experimental periods. Treatments consisted of grass (G) or maize (M) silage supplemented with low (L) or high (H) levels of concentrates (65: 35 and 35: 65, forage: concentrate ratio, on a dry matter (DM) basis, respectively) offered as a total mixed ration at a restricted level of intake (20 kg DM per day). Lipid supplements (30 g/kg DM) containing fish oil and sunflower oil (2: 3 w/w) were offered during the last 14 days of each experimental period. Treatments had no effect on total DM intake, milk yield, milk constituent output or milk fat content, but milk protein concentrations were lower (P<0.05) for G than M diets (mean 43.0 and 47.3 g/kg, respectively). Compared with grass silage, milk fat contained higher (P<0.05) amounts Of C-12: 0, C-14: 0, trans C-18:1 and long chain >= C20 (n-3) polyunsaturated fatty acids (PUFA) and lower (P<0.05) levels Of C-18:0 and trans C-18:2 when maize silage was offered. Increases in the proportion of concentrate in the diet elevated (P<0.05) C-18:2 (n-6) and long chain >= C20 (n-3) PUFA content, but reduced (P<0.05) the amount Of C-18:3 (n-3). Concentrations of trans-11 C-18:1 in milk were independent of forage type, but tended (P<0.10) to be lower for high concentrate diets (mean 7.2 and 4.0 g/100 g fatty acids, for L and H respectively). Concentrations of trans-10 C-18:1 were higher (P<0.05) in milk from maize compared with grass silage (mean 10.3 and 4.1 g/100 g fatty acids, respectively) and increased in response to high levels of concentrates in the diet (mean 4.1 and 10.3 g/100 g fatty acids, for L and H, respectively). Forage type had no effect (P>0.05) on total milk conjugated linoleic acid (CLA) (2.7 and 2.8 g/100 g fatty acids, for M and G, respectively) or cis-9, trans-11 CLA content (2.2 and 2.4 g/100 g fatty acids). Feeding high concentrate diets tended (P<0.10) to decrease total CLA (3.3 and 2.2 g/100 g fatty acids, for L and H, respectively) and cis-9, trans-11 CLA (2.9 and 1/7 g/100 g fatty acids) concentrations and increase milk trans-9, cis-11 CLA and trans-10, cis-12 CLA content. In conclusion, the basal diet is an important determinant of milk fatty acid composition when a supplement of fish oil and sunflower oil is given.
(30-June-2005)
 

 Abramson SM, Bruckental I, Lipshitz L, Moalem U, Zamwel S, Arieli A (2005) Starch digestion site: influence of ruminal and abomasal starch infusion on starch digestion and utilization in dairy cows. Animal Science 80: 201-207 Part 2

KEYWORDS: dairy cows, starch, glucose, small intestine, undegradable crude protein, milk-yield, mechanistic model, performance, propionate, digestibility, fermentation, proposals, casein, steers

SUMMARY: The effect of site of starch digestion on glucose metabolism in dairy cows was studied. Four multiparous Israeli-Holstein cows in mid lactation were used in a 4 X 4 Latin-square design. Average body weight of cows was 580 +/- 38 kg, and average milk yield was 28 +/- 3 kg/day. The cows were fitted with ruminal cannula and flexible T-cannulae in abomasum and ileum. Treatments were as follows: CON (control): water was infused to the rumen. SR (starch-rumen): 1.5 kg/day of maize starch solution was infused into the rumen. SA (starch-abomasum): 1.5 kg/day of maize starch solution was infused into the abomasum. SCA (starch-casein-abomasum) : 500 g/day sodium caseinate and 1.5 kg/day of maize starch solution was infused into the abomasum. Total intake of dry matter (DM), was similar in all treatments and averaged 19.9 kg/day. Total non-structural carbohydrate (TNC) intake averaged 6.8 kg/day. The average TNC digested in the rumen was 4.95 kg/day for CON and SR cows and 3.34 kg/day for the SA and the SCA cows. The average TNC digestion in the small intestine was 1.18 kg/day for CON and SR cows and 2.41 kg/day for the SA and SCA cows. TNC digestibility in the small intestine was highest for the SCA cows at 0.83 as compared with other treatments. Concentrations of plasma glucose and insulin were similar between treatments. No difference between treatments in total volatile fatty acid (VFA) concentration in ruminal fluids was observed. However, propionate proportion in total VF4 was higher in the SR cows than in other treatments (P<0.04). Milk yield and composition were not affected by treatments in the present study. It was concluded that the amount of dietary protein in the small intestine has a considerable effect on TNC digestibility. Under conditions of high milk production and high rumen-by-pass TNC flow, efficiency of TNC utilization might be greater since TNC is digested in the small intestine rather than in the rumen.
(30-June-2005)
 

 Liu D, Liu JX, Zhu SL, Chen XJ, Wu YM (2005) Histology of tissues and cell wall of rice straw influenced by treatment with different chemicals and rumen degradation. Journal of Animal and Feed Sciences 14 (2): 373-387

KEYWORDS: chemical treatment, rice straw, tissue, cell wall, electron microscopy, degradability, scanning-electron-microscopy, digestibility, digestion, stems

SUMMARY: Rice straw (RS) was treated with urea, ammonium bicarbonate (NH4HCO3) and sodium hydroxide (NaOH), respectively. Treatments increased the in sacco dry matter degradability of RS from 45.3 (untreated) to 52.5, 53.2 and 63.6%, respectively (P < 0.01). The untreated and treated RS stem samples were digested in the rumen of a Huzhou sheep for 12, 24, 48 and 72 h and examined for the degradation of tissues and cell walls by using a scanning electron microscope (SEM), and a transmission electron microscope (TEM). Parenchyma was slightly distorted by treatment with urea or NH4HCO3, but severely distorted by NaOH treatment. The chemical treatments had little effect on other tissues of RS stem. All three treatments accelerated the degradation of parenchyma at 12 and 24 h, and NaOH treatment made the parenchyma degraded to most extent. Sclerenchyma cell wall in the untreated RS was slightly digested and still left partial secondary wall and complete middle lamella and primary wall even at 72 h, but NaOH-treated sclerenchyma cell wall began to be degraded at 48 h and just left the middle lamella and occasional primary wall at 72 h. All three treatments made the phloem absent at 48 h, but had little effect on the digestion of epidermis and xylem of vascular tissue. These results indicated that NaOH treatment had the best effects on the modification of structure of rice straw stems and the digestion of tissues and cell wall, and that the positive effects of NH4HCO3 treatment basically paralleled those of urea treatment. The improvement in digestion of histological structures was accordant entirely with the increase of in sacco degradability of RS after the three treatments. It is suggested that the histological methods by means of microscopical techniques such as SEM and TEM are conducive to a direct insight into the mechanism with which chemical treatments exerted the effects on the improvement of nutritive value of RS.
(30-June-2005)
 

He ML, Mir PS, Beauchemin KA, Ivan M, Mir Z (2005) Effects of dietary sunflower seeds on lactation performance and conjugated linoleic acid content of milk. Canadian Journal of Animal Science 85 (1): 75-83

KEYWORDS: conjugated linoleic acids, cow, milk, sunflower seed, long chain fatty-acids, dairy-cows, protozoa population, bovine-milk, CLA content, oil, rumen, supplementation, steers, sheep

SUMMARY: The conjugated linoleic acid (CLA) concentration in milk and the lactation performance of cows fed either a control (CON) or a sunflower seed [SS; 7% of dietary dry matter (DM)] containing diet were compared in a 12-wk lactation trial, starting from week 3 after calving, with 17 multiparous and 8 primiparous cows. The CON and SS diets were isonitrogenous and provided 4 and 6% crude fat in the total mixed rations and were fed to 13 and 12 cows, respectively.The DMI and milk production of the cows fed the CON and SS diets were 20.5 +/- 0.80 and 20.2 +/- 0.80 kg d(-1) (P > 0.05) and 38.2 +/- 1.71 and 38.2 +/- 1.71 kg d(-1) (P > 0.05), respectively. No differences due to diet were observed for cow body weight, body condition score, or for content and yield of milk fat, protein and lactose. The CLA cis-9, trans-11 concentration in milk from cows fed the CON and SS diets was 3.9 and 7.9 mg g-1 fatty acids (P < 0.01), respectively. The average CLA cis-9, trans-11 yield in milk from cows fed CON and SS diets was 5.1 +/- 0.07 and 10.9 +/- 0.07 g d-1, respectively, or 114% greater (P < 0.05) for cows fed the SS diet. The study indicates that sunflower seed inclusion at 7% of dietary DM to dairy cows increases the CLA concentration and yield in milk, without affecting DMI, milk production or composition.

 Stemme K., Gerdes B., Harms A., Kamphues J. (2005) “Beet-vinasse (condensed molasses solubles) as an ingredient in diets for cattle and pigs nutritive value and limitations”. Journal of Animal Physiology and Animal Nutrition, (89), 3-6, pp 179

KEYWORDS. Beet-vinasse, Cattle, Nutrition.

SUMMARY: Sugar beet vinasse, originating as the condensed molasses residue from yeast production, was fed to bulls and pigs to determine the feed value. It contained, per kg dry matter (DM content 66.8%), 293 g crude protein, 305 g N-free extract (therefrom 34.4 g total sugar), and 395 g crude ash. The experiment was carried out with three fattening bulls (German Holstein) and four adult pigs (Göttingen Minipig). In bulls, two balance trials lasting 20 days each (10 days adaptation; 10 days collection) were conducted in which subsequently a basal ration without and with vinasse (14% in DM) was fed. In pigs, the experiment consisted of three 12-day balance trials with the final 5 days as collection period. In the first trial, pigs received a basal diet without vinasse and in the following, a mixed diet with 16 and 43% vinasse (in DM) respectively. Digestibilities of components in vinasse in bulls were: organic matter 73.5%, crude protein 72.6%, and N-free extract 52.3%. In bulls, no influence on faeces quality could be detected while feeding 14% vinasse in DM. While feeding 16% vinasse in DM to pigs, the digestibility of organic matter amounted to 72.3% (crude protein 71.8%; NfE 74.6%). Feeding higher amounts of vinasse (43% in DM) in the diet of pigs, digestibilities were reduced (organic matter: 61.6%), which might be a result of a reduced retention time of the chyme as a result of an osmotically driven diarrhoea because of unexpectedly high sulphate (136 g/kg DM) content in the vinasse. It is concluded that because of organic matter digestibility >70% for cattle and pigs, the use of vinasse in these species in small proportions is reasonable.
(10-May-2005)
 

Aharoni Y., Brosh A., Harari Y. (2005) “Night feeding for high-yielding dairy cows in hot weather: effects on intake, milk yield and energy expenditure”. Livestock Production Science (92) 3 pp 207-219

KEYWORDS: Dairy cattle, Night feeding, Intake, Milk yield, Energy expenditure, Climate

SUMMARY: Heat load impairs the feed intake and milk yield of dairy cows: The higher their milk yield and energy expenditure (EE), the larger the expected effect. Our objective was to examine the efficacy of feeding such cows at night, which avoiding their access to feed for 5 1/2 h during the hot hours of the day, to reduce the heat load upon them in a hot climate. Approximately 120 cows in a herd in a hot region in Israel were allocated to two treatments: day (DFT) or night (NFT) feeding, which differed only in the schedule of feed allocation. The experiment was conducted from May to September 2000 (118 days). The cows were group fed on a total mixed ration, and the daily amounts of feed offered and of orts collected were recorded. The daily group average milk yield was also recorded. Ten cows in each group were selected for individual measurements. The energy expenditure of these cows was estimated once before and three times during the experiment, by monitoring heart rates and measuring oxygen consumption. The rectal temperatures and respiration rates (RR) of these cows were measured in the morning and afternoon on two consecutive days in August. Cows on NFT had lower feed intake but similar milk yield to that of DFT cows, and NFT cows had better milk yield persistence over time. The effects of the temperature–humidity index (THI) on milk yield and intake were similar in the two treatments. The rectal temperature and respiration rate, and the increase in these measures from morning to afternoon hours, did not differ from DFT and NFT cows. The energy expenditure of NFT cows was lower than that of DFT cows, and their efficiency of energy utilization for milk production was higher.
(9-May-2005)
  

Marini J. C., Van Amburgh M. E. (2005) “Partition of Nitrogen Excretion in Urine and the Feces of Holstein Replacement Heifers”. Journal of Dairy Science (88) 5 pp 1778-1784

KEYWORDS: manure, nitrogen, replacement heifer

SUMMARY: Increasing public concern has been focused on animal production systems as a major nonpoint source of pollution. These studies were conducted to further our understanding of whole-animal N metabolism, N excretion, and its partition between feces and urine in growing dairy heifers. Isocaloric diets [2.31 Mcal of metabolizable energy (ME)/kg of dry matter (DM)], ranging from 12.4 to 34.2 g of N/kg of DM, were fed to Holstein heifers in 2 experiments at approximately 1.8 times maintenance. Diets were formulated to provide 54 to 143% of the ruminal ammonia requirements as predicted by the Cornell Net Carbohydrate and Protein System. Increasing the N content of the diet increased urinary N excretion and N balance, but did not affect fecal N excretion. Holstein heifers fed low N diets were able to maintain growth rates consistent with current recommendations while at the same time reducing N excretion, in particular nitrogenous compounds that are readily converted to ammonia. However, more research is needed before this type of diet is recommended for growing heifers because of possible changes in body composition that may affect future milk production and performance.
(9-May-2005)
  

Descalzo AM, Insani EM, Biolatto A, Sancho AM, Garcia PT, Pensel NA, Josifovich JA (2005) Influence of pasture or grain-based diets supplemented with vitamin E on antioxidant/oxidative balance of Argentine beef. Meat Science 70 (1): 35-44.

KEYWORDS: Argentine beef; pasture- and grain-fed cattle; vitamin E; supplementation; natural antioxidants; lipid oxidation; fatty acid composition; volatile compounds; fatty-acid-composition; lipid stability; oxidative stability; modified atmosphere; alpha-tocopherol; color stability; ground-beef; beta-carotene; mixed diet; fresh beef

SUMMARY: Argentine meat has been traditionally produced on pasture. However, to comply with some market requirements, grain finishing is becoming more common among producers. The main goal of the present work was to study lipid oxidation in fresh meat from animals fed different diets in relationship with their antioxidant vitamin status. Attributes were evaluated in beef from pasture or grain-fed animals with (PE and GE) or without supplementation (P and G) with vitamin E (500 UI/head/day). Fresh meat produced on grain (G and GE) had higher fat (4.0 +/- 1.6 and 4.7 +/- 1.4 g/100 g) and cholesterol content (51.0 +/- 3.0 and 52.0 +/- 4.0 mg/100 g) than meat from pasture (P and PE) fed animals (2.7 +/- 1.2 to 2.9 +/- 1.1 g/100 g and 48.0 +/- 5.0 to 49.0 +/- 4.0 mg/100 g of intramuscular fat and cholesterol respectively). Fatty acid composition was clearly affected by diet. Beef from pasture-fed cattle had higher percentage of linolenic acid, less linoleic acid and, overall, higher percentage of polyunsaturated fatty acids than beef from grain-fed animals (P < 0.05).
Thiobarbituric acid reactive substances number and volatile levels of hexanal, pentanal, heptanal, octanal and 3-methylbutanal were higher in grain than in pasture samples (P < 0.05). P + PE meat had higher content of antioxidant vitamins than G + GE samples (P < 0.001). Values ranged from: 15.92 +/- 3.48 (G) to 17.39 +/- 4.29 (GE) and 25.3 +/- 10.0 (P) to 21.98 +/- 5.11 (PE) microg/g of ascorbic acid; from 1.05 +/- 0.73 (G) to 1.76 +/- 0.97 (GE) and 3.08 +/- 0.45 to 3.91 +/- 0.74 microg/g of alpha-tocopherol; and from 0.06 +/- 0.03 (G) to 0.05 +/- 0.01 (GE) and 0.45 +/- 0.21 (P) to 0.63 +/- 0.27 (PE) microg/g of beta-carotene. In addition, principal component analysis clearly separated grain from pasture samples regardless of their supplementation with vitamin E. This level of supplementation did not improve the antioxidant status of fresh meat (P > 0.05). We conclude that pasture diet contributes natural antioxidants in sufficient amounts and is an efficient way to prevent lipid oxidation in fresh beef.
(6-May-2005)
 

Browne EM, Juniper DT, Bryant MJ, Beever DE (2005) Apparent digestibility and nitrogen utilisation of diets based on maize and grass silage fed to beef steers. Animal Feed Science and Technology 119 (1-2): 55-68.

KEYWORDS: maize silage; grass silage; apparent digestibility; associative; dairy-cows; forage mixtures; milk-production; performance; urea; cattle; wheat

SUMMARY: Substituting grass silage with maize silage in forage mixtures may result in one forage influencing the nutritive value of another in terms of whole tract nutrient digestibility and N utilisation. This experiment investigated effects of four forage combinations being, grass silage (G); 67 g/100 g grass silage + 33 g/100 g maize silage (GGM); 67 g/100 g maize silage + 33 g/100 g grass silage (MMG); maize silage (M). All diets were formulated to be isonitrogenous (22.4 g N/kg dry matter [DM]) using a concentrate mixture. Ration digestibility and N balance was determined using 7 Holstein Friesian steers (mean body weight 411.0 +/- 120.9 kg) in a cross-over design. Inclusion of maize silage in the diet had a positive linear effect on forage and total DM intake (P = 0.001), and on apparent DM and organic matter digestibility (both P = 0.048). Regardless of the silage ratio used, the metabolisable energy concentration of maize silage was calculated to be higher than that of grass silage (P = 0.058), and linearly related to the relative proportions of the two silages in the forage mixture. Inclusion of maize silage in the diet resulted in a linear decline in the apparent digestibility of starch (P = 0.022), neutral detergent fibre (P < 0.001) and acid detergent fibre (P = 0.003). Nitrogen retention, expressed as amount retained per day or in terms of body weight (g/100 kg) increased linearly with maize inclusion (P = 0.047 and 0.046, respectively). Replacing grass silage with maize silage caused linear responses according to the proportions of each forage in the diet, and that there were no associative effects of combining forages. All rights reserved.
(6-May-2005)
 

 Lapierre H, Girard CL, Matte JJ, Lobley GE (2005) Effects of stage of lactation on protein metabolism in dairy cows. Journal of Animal and Feed Sciences 14 (1): 53-62.

KEYWORDS: dairy cow; lactation; folic acid; rumen-protected methionine; leucine; kinetics; growing beef steers; whole-body; intake level; feed-intake; folic-acid; leucine; kinetics; somatotropin; responses; balance

SUMMARY: Forty-two lactating dairy cows were used to determine the interaction between folic acid and methionine dietary supplementation on protein metabolism at 6 and 25 weeks of lactation. Treatments were tested according to a 2 x 3 factorial arrangement, with two levels of methionine (0 vs 18 g of rumen protected methionine) and three levels of folic acid (0, 3, or 6 mg/d per kg of BW of pteroylmonoglutamic acid), equally distributed in 7 blocks of 6 cows each. Whole body leucine kinetics were determined using a constant infusion of L[1-C-13]leucine (1.8 mmol/h). Neither milk production, protein yield or leucine kinetics were affected by treatments. Milk production (45.5 to 35.4 +/- 0.85 kg/d) and protein yield (1.43 vs 1.22 +/- 0.028 kg/d) were higher (both P < 0.001) at 6 vs 25 weeks of lactation. However, total whole body leucine irreversible loss rate was not affected by stage of lactation, but fractional oxidation increased as lactation advanced (0.136 vs 0.156 +/- 0.0065; P=0.03). Whole body protein synthesis was not affected by the stage of lactation (4.14 and 4.08 +/- 0.091 kg/d), but the partition of this synthesis was altered, with 0.453 vs 0.403 +/- 0.0095 (P < 0.001) of leucine used for protein synthesis directed towards milk output. However, absolute rates of non-milk protein synthesis were not affected by the stage of lactation. Although concentrations of IGF- 1, insulin and somatotropin varied with stage of lactation, they did not correlate with protein metabolism. In the dairy cow, the high demand for milk production still represents an important portion of the leucine used for protein synthesis until mid-late lactation.
(6-May-2005)
 

Schils RLM, Verhagen A, Aarts HFM, Sebek LBJ (2005) A farm level approach to define successful mitigation strategies for GHG emissions from ruminant livestock systems. Nutrient Cycling in Agroecosystems 71 (2): 163-175.

KEYWORDS: carbon sequestration; dairy; farm management; greenhouse gases; IPCC; methodology; nitrogen; ruminants; grass/fertilizer-n system; greenhouse-gas emissions; nitrous-oxide emission; ammonia volatilization; nutrient management; dairy system; fertilizer; grassland; cattle; sequestration

SUMMARY: Ruminant livestock systems are a significant source of greenhouse gases (GHGs). Thus far, mitigation options for GHG emissions mainly focused on a single gas, and are treated as isolated activities. The present paper proposes a framework for a farm level approach for the full accounting of GHG emissions. The methodology accounts for the relevant direct and indirect emissions of methane, nitrous oxide and carbon dioxide, including carbon sequestration. Furthermore, the potential trade-off with ammonia volatilisation and nitrate leaching are taken into account. A ruminant livestock farm is represented with a conceptual model consisting of five pools: animal, manure, soil, crop and feed. The carbon and nitrogen inputs, throughputs and outputs are described, and the direct emissions are related to the carbon and nitrogen flows. The indirect emissions included in the methodology are mainly carbon dioxide emissions from energy use and nitrous oxide emissions related to imported resources and nitrogen losses. The whole farm approach is illustrated with a case of two dairy farms with contrasting livestock density and grassland management. It is shown that the inclusion of carbon sequestration and all indirect emissions have a major impact on the GHG budget of the farm. For one farm, the effect of four mitigation options on the GHG emissions was quantified. It was concluded that a whole farm approach of full accounting contributes to a better insight in the interactions between the carbon and nitrogen flows and the resulting emissions, within and outside the farm boundaries. Consequently, the methodology can be used to develop efficient and effective mitigation strategies.
(6-May-2005)
  

Pedraza RM, De Castro FB, Orskov ER (2004) Assessement in vitro of the nutritive value of foliages of Gliricidia sepium(Jacq.) Kunth ex Walp. Cuban Journal of Agricultural Science 38 (2): 151-156.

KEYWORDS: Gliricidia sepium; foliage; gas in vitro; tannins; nutritive value; gas-production; digestibility; tree; phenolics; rumen

SUMMARY: The nutritive value of four samples of foliages of Gliricidia sepium (Jacq.) Kunth ex Walp was assessed in vitro with the use of the technique of gases production including the possible effect of their tannins. The potential of gas production (a + b) and the production rate (c) were determined according to the equation p = a + b (l-e(-ct)). The influence of tannins was also studied through the in vitro gas technique with the addition of polyethylencglycol 4000 (PEG 4000). The results indicated a gas production rate between 0.059 and 0.114 mL h(-1) and a gas production potential between 21.6 and 34.8 mL. The foliages of lower regrowth age and without the inclusion of stems had the best performance (P < 0.001). These values are higher than those of the foliage of other shrubs usually used in ruminant feeding. In each of the foliages studied, there were no significant differences in the gas production accumulated at 6, 48 and 96 h, with or without the use of PEG 4000, which suggests that tannins do not seem to be a limitation for the efficient use of G. sepium in animal feeding.
(6-May-2005)
  

Ceresnakova Z, Chrenkova M, Kopcekova J, Sommer A, Zitnan R (2005) Effect of maize grain treatment on ruminal fermentation and the site and extent of starch digestion in cows. Journal of Animal and Feed Sciences 14 (1): 79-91.

KEYWORDS: maize grain; grain processing; starch; in sacco degradability; intestinal digestibility; rumen fermentation; lactating dairy-cow; corn grain; mechanistic model; protein; degradation; absorption; proposals; tract; rumen; sheep

SUMMARY: Four non lactating cows with rumen and duodenal T-cannules were used in the 2 x 2 Latin square experiment to study the effect of crushed or ground maize grain on ruminal fermentation and on starch outflow from the rumen, ruminal and postruminal starch digestibility. Cows were fed diets consisting of, %: forage 70, maize grain crushed or ground 27, soyabean meal 2 and Vitamix S 1, on dry matter basis. Maize treatment did not affect ruminal fermentation. Total VFA concentration was somewhat increased when the animals were fed ground maize (P > 0.1). Effective starch degradability was higher (P < 0.0 1) for ground (70.7%) than for crushed maize (65. 1 %). Starch passage into the duodenum was higher (P < 0.01) when crushed than ground maize was fed (33.5 vs 21.2%). Postruminal digestibility of starch entering the duodenum was high for both diets (82.2 vs 85.5%; P < 0.0 1). Apparent total GIT digestibility of starch was affected by grain processing (P < 0.05).
(6-May-2005)
  

Cenkvari E, Fekete S, Febel H, Veresegyhazi T, Andrasofszky E (2005) Investigations on the effects of Ca-soap of linseed oil on rumen fermentation in sheep and on milk composition of goats. Journal of Animal Physiology and Animal Nutrition 89 (3-6): 172-178.

KEYWORDS: dairy-cows; metabolism; supplementation; rations; yield; fat

SUMMARY: Six rumen-cannulated wethers were fed by a diet composed of alfalfa hay and concentrate and supplemented by 75 g Ca-soap of linseed oil (5.4% in dry matter, DM) daily. A model trial was performed to detect the effects of the Ca-soap on rumen fermentation parameters and on fibre digestion. Approximately 3 h after feeding Ca-soap, ratio of C2:C3 decreased (from 4.33 to 4.02) and the production of i- and n-butyrate and i- and n-valeriate increased by 28, 5.3, 11.76% and 6.80% respectively. Total volatile fatty acid concentration in rumen fluid did not change (126.1 vs. 126.4 mm) as a result of Ca-soap supplementation. The in vitro trial showed no detrimental influence of Ca-soap on the acid detergent fibre (ADF) degradation. Using feed samples containing Ca-soap to be incubated in tubes, ADF digestion proved to be significantly higher (p < 0.001). Approximately 14 goats (Saanen breed, 30-70 days in lactation) were used to test the effects of Ca-soap on milk composition. Their ration contained alfalfa hay, millet straw and a concentrate. In the experimental group (seven goats) the diet was supplemented with Ca-soap of linseed oil (75 g/animal/day). The milk composition was changed (slightly reduced solid content, sometimes significantly reduced milk fat contents), when Ca-soap was included in the diet of lactating goats.
(6-May-2005)
 

 Hindle VA, Vuuren van AM, Klop A, Mathijssen-Kamman AA, van Gelder AH, Cone JW (2005) Site and extent of starch degradation in the dairy cow - a comparison between in vivo, in situ and in vitro measurements. Journal of Animal Physiology and Animal Nutrition 89 (3-6): 158-165.

KEYWORDS: rumen fluid; grass-silage; degradability; fermentation; digestion; prediction; incubation; enzymes

SUMMARY: Prediction of the supply of glycogenic precursors to dairy cows and the site of degradation of wheat, maize and potato starch (PS) were determined in an in vivo experiment and the results were compared with data obtained from experiments involving in situ nylon bag and in vitro gas production techniques. In a Latin square design experiment four lactating dairy cows fitted with a rumen cannula and T-piece cannulae in the duodenum and terminal ileum, received either a low-starch control diet or diets in which sugar beet pulp in the concentrate mixture had been replaced by wheat, maize or PS. Starch from the different sources was almost completely degraded in the total gastrointestinal tract. For all starches, the rumen was the main site of degradation in vivo. No digestion of PS in the small intestine was observed. In situ results suggested that 14% of wheat starch (WS), 47% of maize starch and 34% of PS escaped rumen fermentation. According to the gas production technique WS ferments quickest and potato slowest. PS had a low degradability during the first 8 (gas production) to 11 (in situ) h. However, according to both in vitro and in vivo measurements rumen degradability of PS was high. The results suggest that in situ and in vitro techniques should be performed in animals that have adapted to starch source to provide a more accurate simulation of the in vivo situation.
(6-May-2005)
  

Mwenya B, Santoso B, Sar C, Pen B, Morikawa R, Takaura K, Umetsu K, Kimura K, Takahashi J (2005) Effects of yeast culture and galacto-oligosaccharides on ruminal fermentation in Holstein cows. Journal of Dairy Science 88 (4): 1404-1412.

KEYWORDS: yeast culture; galacto-oligosaccharides; ruminal fermentation; cow; direct-fed microbials; neutral detergent fiber; saccharomyces-cerevisiae; dairy-cows; nitrogen-utilization; purine derivatives; rumen; steers; sheep; methanogenesis

SUMMARY: Four nonlactating, ruminally cannulated Holstein cows were used in a 4 x 4 Latin square design, balanced for residual effects, to evaluate the effects of supplementing dairy cow diets with yeast culture ( Trichosporon sericeum; YC), galacto-oligosaccharides (GOS), or the mixture of YC and GOS on ruminal fermentation, microbial N supply, in situ degradation, and energy and nitrogen metabolism. Treatments were arranged in a 2 x 2 factorial as follows: 1) basal diet, 2) basal diet plus 10 g/d YC, 3) basal diet plus 2% GOS, 4) basal diet plus a mixture of 10 g/d YC and 2% GOS. Nitrogen losses in urine were lower, and retained N was higher, for cows supplemented with a mixture of YC and GOS. Ruminal pH was lower in cows supplemented with GOS alone compared with other treatments. Total VFA concentration was higher in cows fed control and GOS-supplemented diets than in those fed YC containing diets. The molar proportion of propionate was higher, and the molar proportion of acetate was lower, in cows fed control diets. Microbial N supply was higher in cows fed control diets. There were no major positive effects of supplements observed in this study. However, supplementation of a mixture of YC and GOS had a tendency for synergistic effects on N metabolism and in situ degradation of a soluble fraction of oat straw DM and CP of concentrates compared with supplementation of YC or GOS alone.
(6-May-2005)
 

Saebo A, Perfield JW, Delmonte P, Yurawecz MP, Lawrence P, Brenna JT, Bauman DE (2005) Milk fat synthesis is unaffected by abomasal infusion of the conjugated diene 18 : 3 isomers cis-6, trans-10, cis-12 and cis-6,trans-8,cis-12. Lipids 40 (1): 89-95.

KEYWORDS: linoleic-acid; CLA; dairy-cows; dietary supplementation; body-composition; methyl-esters; isomers; tissues; identification; inhibition; metabolism

SUMMARY: It has been previously established that trans-10,cis-12 CLA is a potent inhibitor of milk fat synthesis. Although the mechanism of this action is not completely understood, it has been speculated that eicosanoid-like metabolites of this isomer formed by the activity of tissue desaturases may be responsible for its activity. The objective of this study was to investigate the effects of an enrichment containing an 18:3 conjugated diene, produced in the metabolism of trans-10,cis-12 CLA, on milk fat synthesis. Three rumen-fistulated Holstein cows (210 +/- 8 d in milk) were randomly assigned in a 3 x 3 Latin square experiment. Treatments were W control, (ii) trans-10,cis-12 CLA supplement (2.1 g/d; positive control), (iii) enrichment providing two conjugated diene 18:3 isomers (2.6 g/d of cis-6,trans-10,cis-12 and 4.0 g/d of cis-6,trans-8,cis-12) and trans-10;cis-12 CLA (2.1 g/d). Treatments were abomasally infused for 5 d at 4-h intervals, and there was a 7-d interval between periods. Milk yield, dry matter intake, and milk protein yield were unaffected by treatments. In contrast, the trans-10,cis-12 CLA supplement reduced milk fat yield by 27%, Whereas the supplement enriched with conjugated diene 18:3 isomers (treatment iii) had no effect on milk fat yield beyond that attributable to its trans-10,cis-12 CLA content. The transfer efficiency of trans-10,cis-12 CLA into milk fat was 25 and 24% for treatments ii and iii, respectively., At the same time, the abomasally infused conjugated diene 18:3 isomers were transferred to milk fat with an efficiency of 33 and 41% for cis-6,trans-10,cis-12 and;cis-6,trans-8,cis-12 18:3, respectively. Overall, short-term abomasal infusion of the conjugated diene 18:3 isomers had no effect on milk fat synthesis, thereby offering no support for an involvement of metabolites of trans-10,cis-12 CLA in the regulation of milk fat synthesis.
(6-May-2005)
  

Anderson RC, Majak W, Rassmussen MA, Callaway TR, Beier RC, Nisbet DJ, Allison MJ (2005) Toxicity and metabolism of the conjugates of 3-nitropropanol and 3-nitropropionic acid in forages poisonous to livestock. Journal of Agricultural and Food Chemistry 53 (6): 2344-2350.

KEYWORDS: toxic plant; Astragalus; Coronilia; Hippocrepis; Indigofera; Lotus; toxic fungi; Arthrinium; Aspergillus; Penicillium; 3-nitropropanol; 3-nitropropionic acid; rumen metabolism; Denitrobacterium; miser var-serotinus; aliphatic nitro-compounds; american astragalus Fabaceae; crownvetch Coronilla-varia; bovine rumen fluid; miserotoxin aglycone; ruminal microorganisms; columbia milkvetch; timber milkvetch; Corynocarpus-laevigatus

SUMMARY: Glycosides of 3-nitro-1-propanol (nitropropanol) and glucose esters of 3-nitro-1-propanoic acid (nitropropionic acid) occur in many forages distributed throughout the world. Systemically, nitropropionic acid irreversibly inactivates succinate dehydrogenase, thereby blocking ATP formation. Nitropropanol is not toxic per se in mammals but is converted to nitropropionic acid by hepatic alcohol dehydrogenase. Nitrotoxins can be metabolized by rumen microbes, which may provide a mechanism for detoxification. At least 20 different ruminal bacteria are known to metabolize the nitrotoxins, but most appear to play a minor role in detoxification. Evidence suggests that an obligate anaerobic nitro-respiring bacterium, Denitrobacterium detoxificans, may be particularly important in conferring protection to animals consuming the nitrotoxins as this bacterium metabolizes the toxins at rates near those by mixed ruminal populations. Rates of ruminal nitrotoxin metabolism can be enhanced by modifying the rumen environment through dietary manipulations, which suggests in vivo enrichment of competent nitrotoxin-metabolizing bacteria such as D. detoxificans.
(6-May-2005)
 

Friggens NC, Andersen JB, Larsen T, Aaes O, Dewhurst RJ (2004) Priming the dairy cow for lactation: a review of dry cow feeding strategies. Animal Research 53 (6): 453-473.

KEYWORDS: dry period; feeding; body condition score; dairy cattle; health; organic nutrient metabolism; body condition; milk-production; dietary-protein; matter intake; postpartum performance; subsequent lactation; late-gestation; holstein cows; parturient paresis

SUMMARY: This paper reviews important aspects of dry cow feeding with emphasis placed on the preparation of the cow for the subsequent lactation. A number of feeding strategies, which have been proposed in recent years, are examined, alongside considerations of the effects of dry period length, levels of body reserves at calving and parity. A number of studies have reported the effect of varying the length of the dry period (in the range 0 to 70 days) on subsequent production and health. An 8 week dry period seems optimal though this should be adjusted to allow for the body condition score of cows at drying off. Avoiding extremes of body condition score at calving is desirable, so condition should be monitored throughout the lactation cycle. Attempting to achieve large changes in body reserves in the dry period has been associated with increased problems postpartum. The feeding strategies that are reviewed are strategies to decrease body mobilisation, prime for body mobilisation, prime the rumen for increased intake, prime for milk protein production and prime for calcium mobilisation and absorption. These strategies are also evaluated relative to their biological basis and reported physiological effects. Feeding high starch feeds in the latter part of the dry period was found not to provide clear benefits in terms of decreasing early lactation body mobilisation or increasing early lactation intake. Strategies aimed at priming the cow for the increased mobilisation of body lipid and body calcium that occurs in early lactation appear more favourable both from the point of view of making biological sense and from the available results reviewed.
(6-May-2005)
  

Kristensen NB (2005) Splanchnic metabolism of volatile fatty acids in the dairy cow. Animal Science 80: 2-9 Part 1.

KEYWORDS: dairy cows; liver; metabolism; ruminal epithelium; volatile fatty acids; portal-drained viscera; intraruminal propionate supplementation; increasing ruminal butyrate; lactating Holstein cows; d-beta-hydroxybutyrate; washed reticulorumen; nutrient metabolism; energy-metabolism; rumen epithelium; growing lambs

SUMMARY: Volatile fatty acids (VFA) are quantitatively important substrates for dairy cows and other ruminants. It has been a central dogma in the nutritional physiology of ruminants that the ruminal epithelium metabolizes a large fraction of VFA during their absorption and consequently a relatively small fraction of VFA is available for peripheral tissues including the mammary gland. New data on splanchnic metabolism of VFA indicate that the ruminal epithelium metabolizes none or small amounts of acetate and propionate absorbed from the rumen. However, the ruminal epithelium has a large fractional uptake of butyrate and valerate during their absorption from the rumen. The liver takes up proportionately 0.9 or more of the absorbed propionate, however multiple factors are involved in regulation of hepatic metabolism and propionate does not determine glucose availability to the cow per se. In light of the quantitative importance of VFA to the dairy cow it is important that future research attempts to bridge the gap between the biology of food degradation/digestion in the gastro-intestinal tract and availability of specific nutrients to the cow which impact intermediary metabolism and nutrient utilization in productive tissues.
(6-May-2005)
  

Kingston-Smith AH, Merry RJ, Leemans DK, Thomas H, Theodorou MK (2005) Evidence in support of a role for plant-mediated proteolysis in the rumens of grazing animals British Journal of Nutrition 93 (1): 73-79.

KEYWORDS: ruminant; grazing; fresh forage; proteolysis; rubisco; 18s leaf protein; lolium-temulentum; fresh forage; leaves; senescence; chlorophyll; degradation; chloroplasts; metabolism; digestion

SUMMARY: The present work aimed to differentiate between proteolytic activities of plants and micro-organisms during the incubation of grass in cattle rumens. Freshly cut ryegrass was placed in bags of varying permeability and incubated for 16 h in the rumens of dairy cows that had previously grazed a ryegrass sward, supplemented with 4 kg dairy concentrate daily. Woven polyester bags (50 mum pore size) permitted direct access of the micro-organisms and rumen fluid enzymes to the plant material. The polythene was impermeable even to small molecules such as NH3. Dialysis tubing excluded micro-organisms and rumen enzymes/metabolites larger than 10 kDa. DM loss was 46.3 % in polyester, 36.2 % in polythene and 38.1 % in dialysis treatments. It is possible that the DM loss within polythene bags occurred due to a solubilisation of plant constituents (e.g. water-soluble carbohydrates) rather than microbial attachment/degradation processes. The final protein content of the herbage residues was not significantly different between treatments. Regardless of bag permeability, over 97 % of the initial protein content was lost during incubations in situ. Electrophoretic separation showed that Rubisco was extensively degraded in herbage residues whereas the membrane-associated, light-harvesting protein remained relatively undegraded. Protease activity was detected in herbage residues and bathing liquids after all incubation in situ treatments. Although rumen fluid contains proteases (possibly of plant and microbial origin), our results suggest that, owing to cell compartmentation, their activity against the proteins of intact plant cells is limited, supporting the view that plant proteases are involved in the degradation of proteins in freshly ingested herbage.
(6-May-2005)
  

Strauss CE, McAllister TA, Selinger LB (2004) Development of Pichia pastoris as a rumen escape vehicle for the intestinal delivery of recombinant proteins in ruminants. Canadian Journal of Animal Science 84 (4): 611-619.

KEYWORDS: ruminal escape vehicle; Pichia pastoris; green fluorescent protein; bypass protein; green fluorescent protein; polysaccharide-degrading enzymes; simulation technique rusitec; amino-acids; in-vitro; ciliate protozoa; dairy-cows; gastrointestinal-tract; duodenal flow; total fauna

SUMMARY: The effectiveness of cellular encapsulation as a method for delivery of bioactive proteins and limiting amino acids to the small intestine of ruminants was investigated. Intracellular expression of green fluorescent protein variant (GFPuv) in Pichia pastoris was used as a visible marker to assess the cellular integrity of P. pastoris and determine the potential of this approach for protecting recombinant proteins from microbial proteolysis in the rumen. Fluorescent cells were easily identified in the presence of strained ruminal fluid when viewed by epifluorescent microscopy, and intact cells were readily enumerated. Batch cultures with rumen digesta demonstrated that 93, 97 and 25% of P. pastoris cells remained intact after 36 to 48 h of incubation in clarified ruminal fluid, an isolated bacterial fraction, and whole ruminal fluid, respectively. In continuous culture (Rusitec) with a dilution rate of 0.75 d(-1), 19% of P. pastoris cells flowed intact from the fermentation vessels. In vitro abomasal simulations demonstrated that 84% of inoculated P. pastoris had lysed within 12 h of incubation, a property that is necessary for the release of encapsulated protein prior to the small intestine. These in vitro studies suggest that P. pastoris may be an effective vehicle for post-ruminal delivery of bioactive proteins in ruminants.
(6-May-2005)
  

Chaucheyras-Durand F, Masseglia S, Fonty G (2005) Effect of the microbial feed additive Saccharomyces cerevisiae CNCM I-1077 on protein and peptide degrading activities of rumen bacteria grown In vitro. Current Microbiology 50 (2): 96-101.

KEYWORDS: proteolytic activities; prevotella-ruminicola; streptococcus-bovis; microorganisms; metabolism; degradation; inhibitors; strain

SUMMARY: We investigated the potential of the ruminant feed additive Saccharomyces cerevisiae CNCM I-1077 on protein and peptide degrading activities of the rumen bacterial species Prevotella albensis M384, Streptococcus bovis 20480, and Butyrivibrio fibrisolvens 3071 grown in vitro. Alive or heat-killed yeast cells were added to bacterial cultures in a complex casein-glucose medium. After incubation of the cultures at 39degreesC under O-2-free CO2, peptidase activities were determined in the absence or in the presence of yeasts. Protease activities were detected after PAGE in gelatin-copolymerized gels. In co-incubations of bacteria and live S. cerevisiae I-1077, proteinase activities were reduced compared to the activities in the bacterial monocultures. Measurement of peptidase activities and microbial enumerations in the co-incubations suggested that live yeasts and bacteria interacted in a competitive way, leading to a decrease in peptidase activities. The mechanism responsible for such an effect could be mainly a competition for substrate utilization, but the release of small competitive peptides by the yeast cells is also likely to be implicated.
(6-May-2005)
  

Socha MT, Putnam DE, Garthwaite BD, Whitehouse NL, Kierstead NA, Schwab CG, Ducharme GA, Robert JC (2005) Improving intestinal amino acid supply of pre- and postpartum dairy cows with rumen-protected methionine and lysine. Journal of Dairy Science 88 (3): 1113-1126.

KEYWORDS: rumen-protected amino acids; lysine; methionine; lactating cow; cottonseed meal protein; heat-treatment; supplemental methionine; undegradable protein; milk-production; lactation; nitrogen; yield; diets; digestibility

SUMMARY: Eighty-four Holstein cows were assigned to a randomized block experiment to determine effects of supplementing pre- and postpartum diets containing high-Lys protein supplements with rumen-protected Met and Lys. Before parturition, cows received a basal diet with 1) no rumen-protected amino acids (AA), 2) 10.5 g/d of Met from rumen-protected Met, or 3) 10.2 g/d of Met and 16.0 g/d of Lys from rumen-protected Met plus Lys. After parturition, cows continued to receive AA treatments but switched to diets balanced for 16.0 or 18.5% crude protein (CP). Diets were corn-based; supplemental protein was provided by soybean products and blood meal. Cows received treatments through d 105 of lactation. Compared with basal and Met-supplemented diets, Met + Lys supplementation increased yield of energy-corrected milk, fat, and protein, and tended to increase production of 3.5% fat-corrected milk. Significant CP x AA interactions were observed only for milk protein and fat content. Supplementation of the 16% CP diet with Met and Met + Lys had no effect on milk true protein and fat content. However, Met and Met + Lys supplementation of the 18.5% CP diet increased milk protein content by 0.21 and 0.14 percentage units, respectively, and Met supplementation increased fat content by 0.26 percentage units. Results of this study indicate that early-lactation cows fed corn-based diets are responsive to increased intestinal supplies of Lys and Met and that the responses depend on dietary CP concentration, supply of metabolizable protein, and intestinal digestibility of the rumen-undegradable fraction of supplemental proteins. It is not clear however if similar results could have been obtained with supplies of non protected Lys and Met.
(6-May-2005)
 

 Dean DB, Adesogan AT, Krueger N, Littell RC (2005) Effect of fibrolytic enzymes on the fermentation characteristics, aerobic stability, and digestibility of bermudagrass silage. Journal of Dairy Science 88 (3): 994-1003.

KEYWORDS: fibrolytic enzyme; bermudagrass; silage; nutritive value; lactating dairy-cows; corn-silage; nutrient digestion; milk-production; in-vitro; cellulase; forages; acid; diet; temperature

SUMMARY: The aim of this study was to determine if the nutritive value and aerobic stability of bermudagrass (Cynodon dactylon) silage could be improved by addition of proprietary, exogenous cellulase/hemicellulase enzyme preparations at ensiling. A 5-wk regrowth of Tifton 85 bermudagrass was conserved without treatment (control) or after treatment with exogenous fibrolytic enzymes including Promote NET (Pr), Biocellulase X-20 (X20), Biocellulase A-20 (A20), and Enzyme CT. The respective enzymes were applied at half the recommended rate, the recommended rate, or twice the recommended rate corresponding to 0.65, 1.3, and 2.6 g/kg of DM, 7.3, 14.5, and 29 mg/kg of DM, at 7.3, 14.4, and 29 mg/kg of DM, and 89, 178, and 356 mg/kg of DM, for Pr, X20, A20, and CT, respectively. The enzymes were sprayed on the bermudagrass at ensiling (not added at feeding as suggested by the manufacturers) to test the objectives of the study. Six 1-kg replicates of chopped (5 cm) forage were ensiled for 145 d in 2.8-L mini silos. Three silos per treatment were used for chemical analysis and 3 for aerobic stability monitoring. The silage juice was analyzed for organic acids, pH, water-soluble carbohydrates (WSC), ammonia-N, and soluble N. Freeze-dried samples were analyzed for crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF). In vitro digestibility of DM (IVDMD), NDF (IVNDFD), and ADF (IVADFD) were determined after digesting the silages in buffered rumen fluid for 6 or 48 h in 2 ANKOM(II) Daisy Incubators. Compared with the other silages, those treated with Pr had lower DM losses, and lower pH and ammonia-N concentration than control silages. Residual WSC concentration was greater in Pr- and CT-treated silages than in control silages and greater in Pr-treated silages than CT-treated silages. Compared with control silages, NDF concentration was lower in silages treated with Pr, X20, and CT, and ADF concentration was lower in silages treated with Pr, X20, and A20. Nevertheless, Pr-treated silages contained lower ADF and NDF concentrations than silages treated with the other enzymes. Enzyme-treated silages contained less acetic acid than control silages, and Pr-treated silages had the lowest concentrations of acetic acid. Aerobic stability was increased by enzyme treatment but microbial counts were not affected. The 6-h IVDMD was increased by treatment with Pr and A20, however only Pr increased the IVDMD and IVNDFD at 48 h. The 48-h lVADFD was also increased by treatment with Pr, CT, and A20. These results show that when applied at ensiling, certain fibrolytic enzymes (particularly Promote) can improve the digestibility, fermentation, and aerobic stability of bermudagrass silage.
(6-May-2005)

Vlaeminck B, Dufour C, van Vuuren AM, Cabrita ARJ, Dewhurst RJ, Demeyer D, Fievez V (2005) Use of odd and branched-chain fatty acids in rumen contents and milk as a potential microbial marker. Journal of Dairy Science 88 (3): 1031-1042.

KEYWORDS: odd and branched-chain fatty acids; microbial protein; dairy cattle; milk; dairy-cows; nitrogen supplementation; chemical-composition; ruminal bacteria; nucleic-acids; duodenal flow; corn silages; purine-bases; diets; fractions

SUMMARY: The objectives of this study were: 1) to determine if a correlation exists between rumen odd and branched-chain fatty acids (OBCFA, i.e., C-15:0, iso C-15:0, anteiso C-15:0, C-17:0, iso C-17:0, anteiso C-17:0, and C-17:1), uracil, and purine bases (PB), 2) to evaluate the potential of milk OBCFA secretion to predict duodenal flow of microbial protein in lactating cows, 3) to evaluate the accuracy of the latter prediction equations using an independent data set, and 4) to determine whether these predictions were more accurate than predictions based on dry matter intake (DMI) and dietary characteristics. In the first experiment, 4 lactating dairy cows arranged in a 4 x 4 Latin square were offered diets based on grass silages of different botanical composition and a standard concentrate. The relationship between rumen pool size of OBCFA and microbial matter was investigated. Rumen pool size of microbial matter (g), determined 4, 12, and 17 h after feeding, using uracil and PB as microbial markers, was closely regulated to OBCFA (g) [r(2) = 0.716, root mean square error (RMSE) = 4.451. To correct for differences in marker concentrations among strains of rumen microbes, C-17:0 was included in the regression equations, resulting in 2 an increased predictive power (r(2) = 0.780, RMSE = 3.92). The relationship between microbial flow to the duodenum and milk OBCFA yield was evaluated in a second experiment with lactating dairy cows offered diets based on grass silage and concentrates differing in starch source. Similar to observations in the rumen, milk OBCFA yield was closely related to microbial flow to the duodenum (RMSE = 4.28), but predictive power of equations did not increase when straight-chain C-17-fatty acids were included in the regression equations (RMSE = 4.92). Evaluation of the current prediction equations with 3 independent datasets resulted in a root mean square prediction error of 20.5 and 13.4% of the observed mean for equations based on milk secretion of total OBCFA and straight-chain C-17-fatty acids, respectively. Comparison of the accuracy of the latter equations with 2 previously published equations based on DMI and dietary characteristics suggest the former to be more accurate. This first evaluation suggests that milk OBCFA could be used as a marker for duodenal flow of microbial matter, especially when accurate measurements of DMI are not available.
(6-May-2005)
 

Kamalak A, Canbolat O, Gurbuz Y (2004) Comparison between in situ dry matter degradation and in vitro gas production of tannin-containing leaves from four tree species. South African Journal of Animal Science 34 (4): 233-240.

KEYWORDS: tree leaves; in situ dry matter degradation; in vitro gas production; tannin microbial protein-synthesis; nutritive evaluation; polyethylene-glycol; nylon bag; rumen; digestibility; browse; invitro; fiber; degradability

SUMMARY: Dry matter (DM) degradation of Glycrrhiza glabra L, Arbutus andrachne, Juniperus communis, and Pistica lentiscus was determined using two different techniques: (i) the in vitro gas production and (ii) the in situ nylon bag degradability technique. Samples were incubated in situ and in vitro for 3, 6, 12, 24, 48, 72 and 96 h. In situ and in vitro DM degradation kinetics were described using the equation y = a + b (1 - e (ct)). At all incubation times except 3 and 72 h the cumulative gas production of J communis was significantly lower than that of G. glabra, A. andrachne and P. lentiscus. At 3, 6 and 12 h incubation times the DM disappearance of J. communis was only significantly lower than that of P. lentiscus. At 24 and 48 h incubation times DM disappearance of J communis was significantly lower than that of A. andrachne and P. lentiscus. There were significant relationships between in vitro gas production and in situ DM disappearance at 24 hi and 96 h incubation times. The gas productions at 24 and 96 h incubation explained 51.2 and 52.4% of variation of DM disappearance, respectively. Gas production from the insoluble fraction (b) alone explained 66.4% of the variation of effective DM degradability (EDMD). The inclusion of gas production from quickly soluble fraction (a) and rate constant (c) of gas production in the regression equation did not improve the accuracy of predicting EDMD. It was concluded that in situ DM disappearance parameters of tannin-containing tree leaves such as used in this present study may be predicted from in vitro gas production parameters.
(6-May-2005)
  

Carvalho LF, Melo DSP, Pereira CRM, Rodrigues MAM, Cabrita ARJ, Fonseca AJM (2005) Chemical composition, in vivo digestibility, N degradability and enzymatic intestinal digestibility of five protein supplements. Animal Feed Science and Technology 119 (1-2): 171-178.

KEYWORDS: enzymatic intestinal digestibility; in vivo digestibility; N degradability; protein supplements; nutritive-value; concentrate feedstuffs; ruminants; meal

SUMMARY: The nutritive value of solvent extract palm kernel meal (SPKM), expeller palm kernel meal (EPKM), copra meal (CM), corn distillers dried grains (CDG) and corn gluten feed (CGF) were evaluated. Apparent in vivo digestibility was measured in rams using increasing levels of supplement studied. Dry matter (DM) and N degradability of feeds after 0, 12 and 16 h rumen incubation and enzymatic digestibility of rumen undegradable protein (UDP) were also determined. It was confirmed that supplements differ significantly in terms of digestibility (energetic value), N degradability and intestinal digestibility of UDP, the figures obtained being consistent with those found in the literature. The low energetic value of SPKM could limit its inclusion in high productive ruminant diets. Although CDG may be considered a good source of UDP, the intestinal digestibility of this fraction was low. Additionally, the relatively high unsaturated fat content of CDG might restrict its incorporation level in ruminant diets.
(6-May-2005)
 

Seymour WM, Campbell DR, Johnson ZB (2005) Relationships between rumen volatile fatty acid concentrations and milk production in dairy cows: a literature study. Animal Feed Science and Technology 119 (1-2): 155-169.

KEYWORDS: rumen; acetate; butyrate; propionate; milk production; dairy cows; grass-legume pasture; corn-silage; lactation performance; alfalfa silage; particle-size; chop length; fed diets; digestion; forage; fermentation

SUMMARY: Data from 20 research studies with 92 treatment means were summarized from the journals of dairy science and animal science 2000-2002. All studies were conducted with Holstein cows in Latin square or simple reversal design and included serial sampling of rumen fluid via cannula. Treatments included the effects of feeding various carbohydrate sources, corn milling byproducts, particle size of forage or grain, level of non-structural carbohydrates and the source and digestibility of forages. Studies included rations based on both stored forages and pasture. Simple statistics, correlation, linear regression and mixed model analysis assessing the random effect of Study were used to describe the relationships between rumen and production parameters. Milk yield was most highly related to rumen concentrations of butyrate (r(2) = 0.47) and propionate (r(2) = 0.23). There was little or no relationship between milk yield and either rumen acetate or total VFA concentration.
Milk yield was related positively to dry matter intake (r(2) = 0.69) and negatively to days in milk (r(2) = 0.25). An improvement in the regression of milk yield was obtained if the theoretical yield of ATP (to the host) per milliliter of rumen fluid was used as the independent variable in place of butyrate alone. Relationships between rumen volatile fatty acid concentrations and milk composition were moderate to weak. Content of milk fat (g/100 g) had a positive association with rumen acetate/propionate ratio (r(2) = 0.26). Milk protein (g/100 g) had a negative relationship with rumen pH (r(2) = 0.17) and a positive relation to days in milk. Rumen butyric acid concentration was positively related to dry matter intake (r(2) = 0.28). Rumen butyric acid concentration had the strongest positive association with milk production and dry matter intake in this data set. The results suggest that in lactating cows increased energy intake is channeled largely through increases in rumen production of butyric and propionic acids and their yield of ATP to the host animal.
(6-May-2005)
 

Jurjanz S, Monteils V (2005) Ruminal degradability of corn forages depending on the processing method employed. Animal Research 54 (1): 3-15.

KEYWORDS: ruminal degradation; corn processing; corn starch; corn fibres; in-sacco degradability; starch degradation; dairy-cows; milk-production; fibrous feeds; crude protein; mixed diet; digestion; maize; rumen

SUMMARY: The in sacco degradabilities of starch and fibre in corn were compared between kernel grains and the whole corn plant before and after ensiling using the nylon bag technique. The same plants were used, in order to exclude the effects of genotype or maturity at harvest. The incubation time course was carried out over 48 h on four cannulated dairy cows. The effective degradability of starch was lower in kernel grains ( 70.2%) than in the whole plant before ( 83.9%) and after ( 92.3%) ensiling. Starch degradation in whole plants was accelerated compared to kernel grains by a shift from the slowly degradable ( from 61.3% to 31.9%) to the rapidly degradable fraction ( from 35.9% to 65.6%) without significantly affecting the degradation constant rate ( 7.7 and 8.0% per h respectively for kernel grains and whole corn plants). The ensiling process improved starch degradation even further compared to whole fresh plants by significantly increasing the rapidly degradable fraction ( 80.7% versus 65.6%) and by a higher degradation constant rate ( 12.4% per h versus 8.0% per h). The fibre degradation was similar between grains and whole corn plants despite differences in their content and composition of NDF. However, ensiling significantly increased the rapidly degradable NDF fraction ( 15.2 versus 9.9%) and doubled its degradation constant rate ( from 1.6% per h to 3.2% per h). This effect was probably due to improved hemicellulose degradation, because cellulose and lignin were not degraded differently between corn plants before and after ensiling. Mechanical cracking such as chopping at harvest improves ruminal starch degradation without altering fibre degradation but the ensiling process simultaneously increases the degradability of starch and fibres.
(6-May-2005)
 

Ungerfeld EM, Rust SR, Burnett RJ, Yokoyama MT, Wang JK (2005) Effects of two lipids on in vitro ruminal methane production. Animal Feed Science and Technology 119 (1-2): 179-185.

KEYWORDS: methane; inhibition; rumen; in vitro; oil; lipids; rumen bacteria; fatty-acids; fermentation; methanogenesis; microorganisms; digestibility; metabolism; inhibitors; rusitec; system

SUMMARY: The effects on mixed ruminal cultures of olive oil (OO) and a hexadecatrienoic acid (HA, cis-C-16:6.9.12) extracted from the Hawaiian algae Chaetoceros were studied in 24 h-batch fermentation. HA at 0.5, 1 and 2 ml/l linearly decreased CH4 Production by 25, 47 and 97%, respectively, while OO did not affect it. HA at 0.5, 1 and 2 ml/l increased H, accumulation by 2-, 2- and 5-fold, respectively. Release of CO2, was linearly decreased by HA at 0.5, 1 and 2 ml/l by 10, 32 and 48%, respectively, while OO linearly increased it by 9, 2 and 17%, at the same concentrations. Apparently fermented OM. as estimated through the VFA production stoichiometry, was linearly decreased by HA at 0.5, 1 and 2 ml/l by 9, 19 and 42%, respectively, while OO did not affect it. HA decreased acetate molar percentage, increased propionate, and tended to decrease butyrate. OO tended to decrease acetate molar percentage, and increased propionate and butyrate molar percentages. HA at 0.5, 1 and 2 ml/l linearly decreased NH4+ concentration by 5, 5 and 21%, respectively. HA was a strong inhibitor of methanogenesis, but decreased fermentation and increased H-2 accumulation. Addition of OO increased propionate production and did not seem to inhibit fermentation.
(6-May-2005)
 

Wang Y, Greer D, McAllister TA (2005) Effect of a saponin-based surfactant on water absorption, processing characteristics and in vitro ruminal fermentation of barley grain. Animal Feed Science and Technology 118 (3-4): 255-266.

KEYWORDS: barley; processing; ruminal fermentation; surfactant; tempering; yucca-schidigera extract; steroidal saponins; feedlot cattle; gas-production; rumen; digestion; performance; degradation; moisture

SUMMARY: The effects of a saponin-based surfactant on tempered barley grain were studied in three in vitro experiments. In Experiment 1, barley kernels were tempered at 220 or 246 g/kg moisture with surfactant included at 0, 60 or 120 mul/kg dry matter (DM). Surfactant increased (P < 0.05) the rate of water uptake during the initial 2 h of tempering, but not if tempering was extended beyond 4 h. Experiment 2 evaluated effects of surfactant on barley grain processing characteristics. l/kg DM during tempering ofmSurfactant was included at 0, 60, 120, or 240  barley (190 g/kg moisture; 2 or 4 h), then the barley was processed with rollers set 2.032, 2.223 or 2.413 mm apart. Surfactant did not affect (P > 0.05) the processing index (PI) of the barley or the particle size distribution. Increasing the roller distance from 2.032 to 2.413 mm increased (P < 0.05) the PI and the proportion of particles with 3.35-4.75 nun diameter, and reduced (P < 0.05) the proportions of particles larger than 4.75 mm or smaller than 2.36 mm. No surfactant x roller distance interactive effects on processing characteristics were observed. In Experiment 3, barley was tempered (190 g/kg l/kg DM and processed with rollersmmoisture; 2 h) with surfactant at 0 or 120  at 2.032 or 2.413 mm, then incubated in batch culture with surfactant /kg DM. Apparent in vitro dry matter digestibilitymsupplemented at 0 or 360  (IVDMD) and gas production were higher (P < 0.01) with rollers at 2.032 mm than at 2.413 mm. Irrespective of substrate particle size, applying surfactant during tempering and/or prior to incubation reduced (P < 0.05) the 4 h IVDMD, accumulation of volatile fatty acids (VFA) and reducing sugars, and molar percentage of acetic acid in the VFA, but it increased (P < 0.05) the molar percentage of butyric acid. The acetate: propionate ratio at 4 h was reduced (P < l/kgml/kg DM) and/or after (360m0.05) by surfactant applied during (120  DM) tempering if the barley had been rolled at 2.032 mm, but at 2.413 mm roller spacing this effect on acetate: propionate was observed only with the maximum l/kg DM). Despite enhancing the initialmapplication of surfactant (120 + 360  rate of water absorption by barley kernels, surfactant applied during tempering did not affect the processing characteristics of barley. Added during or after tempering, surfactant reduced the extent of IVDMD measured at 4 h, but not at 24 h.
(6-May-2005)
 

Gonthier C, Mustafa AF, Berthiaume R, Petit HV, Ouellet DR (2004) Feeding micronized and extruded flaxseed to dairy cows: Effects on digestion and ruminal biohydrogenation of long-chain fatty acids. Canadian Journal of Animal Science 84 (4): 705-711.

KEYWORDS: flaxseed; ruminal biohydrogenation; fatty acid; heat treatment; lactating cows; milk-composition; dietary-fat; digestibilities; soybeans; steers; rumen; corn; seed; flow

SUMMARY: Four lactating Holstein cows fitted with ruminal and duodenal cannulae were used in a 4 x 4 Latin square study to determine the effects of feeding micronized and extruded flaxseed on ruminal biohydrogenation (BH) and digestibility of fatty acids (FA) in the gastrointestinal tract. Four diets were formulated: a control diet with no flaxseed (C); a raw flaxseed diet (RF); a micronized flaxseed diet (MF); and an extruded flaxseed diet (EF). Flaxseed diets contained 126 g kg(-1) flaxseed (dry matter basis). Experimental periods (n = 4) consisted of 21 d of diet adaptation and 7 d of data collection. Flaxseed supplementation increased (P < 0.05) intake of individual long-chain FA, reduced (P < 0.05) ruminal BH of total unsaturated C-18, and increased (P < 0.05) duodenal flow of individual long-chain FA except for C-18:2. Feeding flaxseed increased (P < 0.05) post-ruminal digestibility of C-18:1, C-18:2 and C-18:3 and total tract digestibility of C-16:0, C-18:2, C-18:3, and of total long-chain FA. Heat treatment had no effect on ruminal 9R duodenal flow and digestibility of unsaturated FA. Ruminal BH of C-18:3 was higher (P < 0.05), while the duodenal flow of C-18:3 was lower (P < 0.05) for cows fed EF than for those fed ME Intake and duodenal flow of C-16:0 were higher (P < 0.05) for cows fed MF relative to those fed EF. It was concluded that inclusion of flaxseed in dairy cow diets increased duodenal flow of polyunsaturated FA. However, heat treatments were not effective in protecting unsaturated FA from ruminal BH.
(6-May-2005)
 

Ryhanen EL, Tallavaara K, Griinari JM, Jaakkola S, Mantere-Alhonen S, Shingfield KJ (2005) Production of conjugated linoleic acid enriched milk and dairy products from cows receiving grass silage supplemented with a cereal-based concentrate containing rapeseed oil. International Dairy Journal 15 (3): 207-217.

KEYWORDS: conjugated linoleic acid; cheese; butter; milk fat; lactating Holstein cows; fatty-acid; bovine-milk; canola oil; cis-9,trans-11-octadecadienoic acid; plasma-cholesterol; butter-fat; humans; feed; biohydrogenation

SUMMARY: Opportunities for the production of milk and dairy products enriched with cis-9, trans-11 conjugated linoleic acid (CLA) were investigated. Eighteen mid-lactation cows were used in a continuous-design for 7 weeks. During the first week, cows received grass silage ad libitum supplemented with 10 kg per day of a cereal-based concentrate (control) that was replaced with a concentrate containing 50 g kg(-1) of rapeseed oil (RO). Changes in milk fatty acid composition were monitored on a weekly basis and milk produced was used to manufacture Edam cheese and butter. Inclusion of RO in the concentrate supplement increased the mean levels of trans-octadecanoic, monounsaturated, CLA and polyunsaturated fatty acid in the milk fat from 1.6, 25.7, 0.46 and 2.8 to 4.3, 35.3, 1.02 and 3.9 g 100 g(-1) total fatty acids, respectively. In contrast, the mean level of saturated fatty acids decreased from 71.4 to 60.7g 100 g(-1) total fatty acids. Changes in milk fatty acid composition due to RO occurred within 7 days, with responses reaching a plateau after 21 days. Furthermore, the CLA concentrations in the milk fat from individual cows ranged between 0.37 and 0.65 and 0.43 and 2.06 g 100 g(-1) total fatty acids for the control and RO diet, respectively. CLA enriched milk was used successfully to manufacture of Edam cheese and butter with softer textures but with acceptable organoleptic and storage properties. Processing milk into butter or cheese had no effect on the CLA concentrations indicating that enrichment of dairy products is dependent on the content in raw milk fat.
(6-May-2005)
 

Dymnicka M, Klupczynski J, Lozicki A, Micinski J, Strzetelski J (2004) Polyunsaturated fatty acids in M-longissimus thoracis of fattening bulls fed silage of grass or maize. Journal of Animal and Feed sciences 13: 101-104 Suppl. 2.

KEYWORDS: beef cattle; PUFA; grass silage; maize silage.

SUMMARY: The polyunsaturated fatty acid (PUFA) content of M. longissimus thoracis was determined in Hereford, Limousine and Charolais fattening bulls fed concentrate and maize or grass silage as the basic feed for 7 months. The PUFA n-3 content was higher in Charolaise bulls than in other breeds, and was significantly higher in animals fed on grass than on maize silage. The ratio of PUFA n-6/n-3 was the most advantageous in Hereford bulls.
(6-May-2005)

Lapierre H, Berthiaume R, Raggio G, Thivierge MC, Doepel L, Pacheco D, Dubreuil P, Lobley GE (2005) The route of absorbed nitrogen into milk protein. Animal Science 80: 10-22 Part 1.

KEYWORDS: amino acids; dairy cows; liver; mammary glands; small intestine; lactating Holstein cows; portal-drained viscera; amino-acid utilization; growing beef steers; dairy-cows; mammary-gland; splanchnic metabolism; mesenteric vein; gastrointestinal-tract; hepatic-metabolism

SUMMARY: A database reviewing the metabolism of nitrogen (N) compounds from absorption to milk has been compiled from 14 published and unpublished studies (33 treatments) that measured the net flux of N compounds across the splanchnic tissues in dairy cows. Apparent N digestibility averaged 0.65, with this then partitioned between 0.34 excreted in urine and 0.31 secreted as milk. Nitrogen metabolites are absorbed from the lumen of the gut into the portal vein, mainly as free amino acids (AA) and ammonia; these represented 0.58 and 0.57 of digested N, respectively. All of the ammonia absorbed was removed by the liver with, as a result, a net splanchnic flux of zero. Detoxification of ammonia by the liver and catabolism of AA results in production of urea as an end-product. Hepatic ureagenesis is a major cross-road in terms of whole body N exchange, being the equivalent of 0.81 of digested N. Therefore, salvage of a considerable part of this ureagenesis is needed to support milk protein synthesis. This salvage occurs via transfer of urea from the blood circulation into the lumen of the gut. On average, 0.47 of hepatic ureagenesis was returned to the gut via the portal-drained viscera (equivalent to 0.34 of digested N) with 0.56 of this then used for anabolic purposes e. g. as precursor N for microbial protein synthesis. On average, 0.65 of estimated digestible AA was recovered in the portal vein. This loss (0.35) is due to oxidation of certain AA across the gut wall and non-absorption of endogenous secretions. The magnitude of this loss is not uniform among AA and varies between less than 0.05 for histidine to more than 0.90 for some non-essential AA, such as glutamine. A second database (six studies, 14 treatments) was constructed to further examine the subsequent fate of absorbed essential AA. When all AA are aggregated, the liver removed, on average, 0.45 of portal absorption but this value hides the considerable variation between individual AA. Simplistically, the AA behave as two major groups : one group undergoes very little hepatic removal and includes the branched-chain AA and lysine. For the second group, removal varies between 0.35 and 0.50 of portal absorption, and includes histidine, methionine and phenylalanine. For both groups, however, the efficiency of transfer of absorbed AA into milk protein decreases with increasing supply of protein. This loss of efficiency is linked directly with increased hepatic removal of AA from the second group and, probably, increased catabolism by peripheral tissues, including the mammary gland, of AA from the first group. Therefore, we must stop using fixed factors of conversion of digestible AA to milk in our predictive schemes and acknowledge that metabolism of AA between delivery from the duodenum and conversion to milk protein will vary with nutrient supply. New information evolving from re-analysis of the literature and recent studies will allow better models to be devised for the prediction of nutrient-based responses by the lactating cow. Consideration of biological efficiency, rather than maximal milk yield, will lead to systems that are economically more sensible for the farmer and that have better environmental impacts.
(6-May-2005)

Schroeder G. F., Gagliostro G. A., Bargo F., Delahoy J. E., Muller L. D. (2004) “Effects of fat supplementation on milk production and composition by dairy cows on pasture: a review”. Livestock Production Science, (86), 1-3 pp 1-18

KEYWORDS: Dairy cattle, fat supplementation, milk production and composition

SUMMARY: Eighteen experiments involving 25 comparisons were reviewed to describe the main effects of fat supplementation on milk production and composition with grazing dairy cows. Results were analyzed comparing the fat supplemented and the control groups without supplemental fat, and were segmented according to the stage of lactation (early- or midi-lactation) and the degree of saturation of the fat supplement (unsaturated or saturated). Fat supplements, both saturated and unsaturated, did not affect ruminal fiber digestion. Pasture and total dry matter intake were not consistently affected by fat supplementation. Milk and 4% fat-corrected milk production were increased by 0.97 and 1.05 kg/cow per day with fat supplementation. Milk response to fat supplementation was higher in midi-lactation cows and when saturated fat sources were fed. Milk fat concentration was increased 5.1% with saturated fat supplementation and decreased 8.0% with unsaturated fat supplementation when compared to control groups. Feeding unsaturated fats increased long-chain unsaturated fatty acids in milk fat including conjugated linoleic acid. Milk protein concentration was reduced by feeding unsaturated fat supplements, although milk protein yield was not affected. The experimental results reviewed suggest that fat supplementation to the diet of dairy cows grazing high-quality pastures generally increases milk production although the effects on milk composition depend on the degree of saturation of the fat supplement.
(31-3-2005)
 

Koenig KM, Beauchemin KA, Rode LM.(2004). Effect of protein source on microbial protein synthesis and nutrient digestion in beef cattle fed barley grain-based diets. Canadian Journal of Animal Science, 84 (3): 481-490.

KEYWORDS: rumen protein degradability, rumen microbial protein synthesis

SUMMARY: Four British cross heifers fitted with ruminal and duodenal cannulas were used in an experiment designed as a 4 x 4 Latin square. The basal diet was composed of 90% barley grain concentrate and 10% barley silage (DM basis) with either no protein supplementation (13.6% CP), or an additional 1.2% CP (% of DM) in the form of urea, canola meal (CM) or blood meal (BM). Ruminal ammonia N concentration and ruminal pH were not affected by protein source .Canola meal and BM tended (P < 0.10) to increase microbial N flow by 31 g N d-1 or 21% above the control diet and the response of microbial N flow to urea supplementation was intermediate between the control and true protein sources (P > 0.10). Ruminal OM and starch digestion were not affected by the dietary treatments (P > 0.10). In conclusion, barley grain-based finishing diets supplemented with protein sources of varying ruminal degradability’s increased microbial protein supply, but the improvement in microbial protein synthesis had no effect on diet fermentability.
(28-Feb-2005)
 

Poulson CS, Dhiman TR, Ure AL, Cornforth D, Olson KC. (2004). Conjugated linoleic acid content of beef from cattle fed diets containing high grain, CLA, or raised on forages. Livestock Production Science, 91 (1-2): 117-128.

KEYWORDS: beef fatty acids, pasture, CLA, rumen fatty acids

SUMMARY: Twenty Angus crossbred steers were assigned to one of four treatments and followed from weaning to slaughter to study the effect of diet on the conjugated linoleic acid (C18:2 cis-9, trans-11 and C18:2 trans-10, cis-12 CLA isomers) content and quality of beef. During the adaptation period, treatments 1 (CTL), 2 (CLA), and 3 (GPS) received a diet consisting of 520 g corn silage, 213 g alfalfa hay, 250 g rolled barley, and 17 g mineral–vitamin premix/kg of dry matter (DM). Treatment 4 (PS) received alfalfa hay only. During the finishing period, CTL and CLA steers received a diet consisting of 123 g corn silage, 67 g alfalfa hay, 764 g rolled barley, and 46 g mineral–vitamin premix/kg of diet dry matter. In addition to the basal diet, CLA steers received 84 g/head/day of a synthetic mixture of partially rumen protected CLA isomers. The GPS and PS treatments were finished solely on pasture. Beef tissues from PS and GPS steers had 466% (1.31 g/100g FA) and 218% (0.80 g/100G FA) more CLA (C18:2 cis-9, trans-11 isomer) at slaughter compared with beef tissues from CTL steers, respectively. The results suggest that there may be a greater efficiency of conversion from 18:1,t11 into 18:2,c9t11 in ST compared to LD muscle. Supplementing synthetic CLA did not increase C18:2 cis-9, trans-11 CLA content of beef, but increased trans-10, cis-12 CLA by 380% compare to beef from CTL animals. A trained taste panel detected no differences in tenderness or juiciness among treatments. However, beef from PS received higher off-flavour scores than other treatments. Raising cattle on forage and pasture with no grain supplementation enhances beef CLA content. Additionally, finishing cattle on pasture increased the vitamin E content of beef by 300% compared to beef from animals finished on a traditional high-grain diet.
(28-Feb-2005)
 

Vlaeminck B, Fievez V, van Laar H, Demeyer D (2004) Rumen odd and branched chain fatty acids in relation to in vitro rumen volatile fatty acid productions and dietary characteristics of incubated substrates J. Anim. Physiol. a. Anim. Nutr. 88, 401–411.

KEYWORDS: Odd and branched chain fatty acids, rumen, milk fatty acids, volatile fatty acids.

SUMMARY: A first aim of this batch in vitro experiment (21 h) was to use changes in odd and branched chain fatty acid (OBCFA) patterns to suggest shifts in microbial populations, associated with four types of incubated whole dairy cow diets. Principal component analysis suggested higher dietary starch increased the proportion of C15:0 and C17:0, whereas increased neutral detergent fibre content was positively related to anteiso C15:0 concentrations, which is in agreement with the importance of these fatty acids in respectively amylolytic and cellulolytic bacteria. A second aim of the experiment was to relate rumen volatile fatty acid proportions to OBCFA by principal component regression and to compare these relations with predictions based on diet proximate composition. The R2 values achieved for the regressions between acetate, propionate and butyrate, and OBCFA were 79.6%, 86.6% and 84.9% respectively. Moreover, in the current study, predictions of the rumen fermentation pattern showed higher R2 (p < 0.01) when based on OBCFA compared with proximate feed composition. If relations persist in vivo, there could be scope for milk OBCFA to predict the supply of specific rumen nutrients.
(28-Feb-2005)
 

Sylvester JT, Karnati SKR, Yu Z, Morrison M, Firkins JL (2004) Development of an Assay to Quantify Rumen Ciliate Protozoal Biomass in Cows Using Real-Time PCR . J. Nutr. 134: 3378–3384

KEY WORDS: .rumen protozoa . real-time PCR . 18S rDNA . cattle

SUMMARY: Currently used microbial markers cannot distinguish protozoal nitrogen (N) from bacterial N, thus limiting research on protozoal quantification in vivo by the lack of a repeatable, accurate marker for protozoal N. The article reports the development of a real-time PCR assay targeting the gene encoding 18S rDNA to quantify the amount of protozoal biomass in ruminal fluid and duodenal digesta. Protozoal cells were harvested from rumen fluid and concentrated for evaluation of recovery of rDNA in samples from the rumen and the duodenum. The DNA from concentrated cells was extracted with virtually 100% efficiency both before and after column purification. After serial spiking of protozoal cells into duodenal fluid over the entire range of quantification, the recovery was highly linear and constant at 81%. After serially spiking increasing quantities of protozoal rDNA into a constant volume of duodenal samples, nonlinear regression verified constant recovery of background rDNA in duodenal samples regardless of the ratio of target:nontarget rDNA. Recommendations for the procedure, including replication per sample, are described.
In a commentary accompanying the paper, Bergen concludes that adoption of this comprehensive assay will provide new insight into the contribution of rumen protozoa to protein metabolism in ruminants hitherto considered impossible. In time, this new knowledge will result in improved diet formulations and enhanced efficiency of N utilization by ruminants.
(28-Feb-2005)
 

Noci F, O'Kiely P, Monahan FJ, Stanton C, Moloney AP (2005) Conjugated linoleic acid concentration in M-longissimus-dorsi from heifers offered sunflower oil-based concentrates and conserved forages. Meat Science 69 (3): 509-518

KEYWORDS: conjugated linoleic acid, fatty acids, silage, muscle, fatty acids, carcass characteristics, adipose tissue, beef cattle, bovine milk, soybean oil, CLA content, muscle, steers, diet

SUMMARY: The first objective of this experiment was to investigate the relationship between an increase in the dietary supply of C18:2n - 6 from sunflower oil (SFO) and conjugated linoleic acid (CLA) concentration in the muscle tissue of beef cattle. The second objective was to investigate the effect of the basal forage type on the muscle fatty acid composition and its response to increasing inclusion of SFO. One hundred and five heifers were blocked according to initial bodyweight and assigned to one of seven silage treatments. The silage treatments were: (1) grass silage (GS), (2) whole crop wheat silage with 38% dry matter (DM) (W1), (3) GS and W1 at a ratio of 1:2 (DM basis) (WIGS) (4) GS and W1 at a ratio of 2:1 (DM basis) (GSW1), (5) whole crop wheat silage with 52% DM (W2), (6) GS and W2 at a ratio of 1:2 (DM basis) (W2GS), (7) GS and W2 at a ratio of 2:1 (DM basis) (GSW2). Within each silage treatment, 5 animals were assigned to one of three concentrate rations, differing in the content of SFO. The levels of inclusion of SFO in the concentrate were 0, 55, 110 g/kg concentrate. Inclusion of SFO in the diet led to an increase in the n - 6:n - 3 fatty acid ratio in muscle. In animals fed grass silage or mixed silages the n - 6:n - 3 ratio was lower in muscle compared with those fed whole crop wheat silages, with the exception of animals fed 55 g SFO/kg, for which feeding WIGS led to a higher ratio than W1. Other than the n - 6:n - 3 ratio there were no significant interactions between the effect of type of silage and the level of SFO on the concentration of fatty acids in intramuscular fat. Increasing the inclusion of SFO led to a linear increase in the CLA-cis-9,trans-11 and PUFA concentration in intramuscular fat (P < 0.001). This study confirmed the potential for modification, and improvement from a human health perspective, of the fatty acid composition of beef muscle by dietary manipulation.
(28-Feb-2005)