bluuebunny/crossref_metadata_2025 huggingface dataset:
Production of chicken egg yolk antibody (IgY) against bovine proteoglycan
Authors: Li X. , Nakano T. , Chae H. S. , Sunwoo H. , Sim J. S.
Published: March 2010

This study was undertaken to examine the immune response of chickens to bovine decorin, which is a proteoglycan bearing a single chain of dermatan sulphate. Three 35-wk-old Single Comb White Leghorn hens were immunized with decorin by intramuscular injection, and eggs produced by each bird were examined by ELISA for anti-decorin antibody activity in the yolk. The antibody activity started to increase 7 d after immunization, rapidly increased and remained relatively constant after 35 d. The polyclonal antibody obtained was then examined by ELISA inhibition assay with samples of bovine decorin treated with and without enzymes. Digestion of decorin with papain to cleave its protein core caused a complete loss in antigenicity, while chondroitinase-ABC treatment to cleave its dermatan sulphate chain showed no appreciable effect. This indicates that the protein core but not the dermatan sulphate chain was recognized by the anti-decorin antibodies. Immunohistochemical staining located the antigen in bovine, porcine and chicken tissues. It is concluded that chickens can efficiently produce specific antibodies to the protein core of bovine decorin. Key words: Chicken, proteoglycan, decorin, antibody, immune response
Effects of gonadotropins and insulin-like growth factors-I and -II on in vitro steroid production by bovine granulosa cells
Authors: Yang M. Y. , Rajamahendran R.
Published: March 2010

The objectives of this study were: 1) to develop a bovine granulosa cell (GC) culture system; and 2) to use this system to evaluate the effects of gonadotropins (FSH and LH) and insulin-like growth factors-I and -II (IGF-I and IGF-II) on steroidogenesis of bovine GC derived from small, medium, and large antral follicles (diameters ≤4, 5–8 and >8 mm, respectively). Granulosa cells were cultured (concentration, 5 × 105 cells per well) in serum-free medium for 48 h with variable doses of hormones and growth factors. Concentrations of progesterone (P4) and estradiol-17β (E2) in the media were determined by radioimmunoassay. Basal E2 production by GC from follicles of all sizes decreased with time of culture (P < 0.01) while basal P4 production increased (P < 0.01). Basal E2 and P4 production increased with increasing size of follicles (P < 0.01). Only very low concentrations of FSH stimulated E2 production from medium and large follicles. Follicle-stimulating hormone stimulated P4 production by GC of follicles of all sizes (P < 0.05). Luteinizing hormone inhibited E2 production by GC in medium and large follicles (P < 0.05), suggesting that LH is responsible for the rise in plasma E2 through effects on both theca cells and GC. A dose of 100 ng mL−1 of IGF-I increased E2 production by GC from medium and large follicles (P < 0.05). Progesterone production by GC from all categories of follicles was also stimulated by IGF-I (P < 0.05). Estradiol-17β production by GC from large follicles decreased in response to IGF-II (P < 0.05). The physiological role of IGF-II on steroidogenesis in the bovine ovary remains to be elucidated. In summary, these results demonstrate the development of a serum-free culture system for bovine GC, and that FSH, LH, IGF-I and IGF-II have different effects on steroidogenesis by bovine GC from different size follicles. Key words: Granulosa cells, gonadotropins, Insulin-like growth factors, progesterone, estradiol-17β, cows
In vitro and in situ nutrient degradability of barley and wheat milling byproducts
Authors: Mustafa A. F. , McKinnon J. J. , Christensen D. A.
Published: March 2010

A study was conducted to estimate nutrient degradability of barley milling byproducts (BMBP) using in vitro and in situ techniques. Three levels of milling (5.9, 9.5 and 17%), representing the proportion of byproduct to the original grain weight were tested. A wheat byproduct (WMBP), milled at 5.9% was used for comparison. Results indicated that 5.9% WMBP was more degradable than the BMBP. Within the BMBP, the 17% BMBP was more degradable than the 5.9 and the 9.5% BMBP. No differences in nutrient degradability were observed between the 5.9 and the 9.5% BMBP. Key words: Barley, wheat, milling byproducts, nutrient degradability
Genetic parameters for milk yield and litter size in Boutsico dairy sheep
Authors: Kominakis A. , Rogdakis E. , Koutsotolis K.
Published: March 2010

Lactation and litter size records (n = 2553) of Boutsico dairy sheep were used to estimate direct additive, maternal genetic, maternal and animal's permanent environmental variance components for milk yield and litter size by restricted maximum likelihood under a repeated records animal model. Raw milk yield data were transformed by log and Box–Cox (BC) transformations. Heritability estimates of direct additive effects were between 0.21 and 0.30, 0.18 and 0.24 and 0.21 and 0.27 for untransformed, log transformed and BC transformed data, respectively. Only maternal and animal's environmental effects were important for milk yield. Direct-maternal genetic covariance did not significantly (P > 0.05) influence milk yield. Repeatability for milk yield ranged from 0.32 to 0.38. Only additive genetic effects were important for litter size. Heritability and repeatability for litter size were 0.07 and 0.11, respectively. Genetic and phenotypic correlations between yield and litter size were 0.13 and 0.19, respectively. Key words: Sheep, milk yield, litter size, heritability, correlation
Prediction of the performance of broiler chicks from apparent metabolizable energy and protein digestibility values obtained using a broiler chick bioassay
Authors: Scott T. A. , Silversides F. G. , Classen H. L. , Swift M. L. , Bedford M. R.
Published: March 2010

Samples of wheat (54) and barley (87) were included in a series of broiler chick bioassays. For each cereal, fed at 80% of a basal diet with or without enzyme, apparent metabolizable energy (AME), retained nitrogen, digesta viscosity, excreta dry matter (DM), and broiler performance (feed intake, body weight [BW] gain, and feed conversion) were measured. Correlation coefficients were calculated between the predictor and the performance variables, separated according to whether or not the diets included feed enzymes. Some correlations between measures of AME and BW, feed efficiency, and to a lesser degree feed intake were significant, but none were high. The correlation coefficients were higher when feeds were not supplemented with an enzyme because enzyme supplementation reduced the variation in both AME and performance by reducing the antinutritive effects of non-starch polysaccharides (NSP). Including a measure of voluntary intake in AME (AME level multiplied by feed intake) resulted in higher correlations with performance. Evaluation of the feeding value of wheat and barley by researchers or the feed industry will require the determination of available energy and the NSP contents. Key words: Metabolizable energy, performance, wheat, barley, feed enzymes
Effects of lighting program on reproductive development of female large white turkeys
Authors: Melnychuk V. L. , Robinson F. E. , Renema R. A. , Hardin R. T. , Emmerson D. A.
Published: March 2010

Female commercial turkeys were used to investigate the effects of lighting program on onset of egg production, reproductive development and egg production. Under a conventional (CON) lighting program, birds were photostimulated from 5L:19D to 14L:10D at 29 wk, with an additional hour of daylight added at 35 wk of age (15L:9D). The alternate (ALT) lighting program involved weekly 0.5 h decreases in day length from 14L:10D at 3 d to 6L:18D, at 17 wk followed by weekly 0.5-h increases in day length beginning at 20 wk, to a maximum of 15L:9D at 38 wk of age. Birds were killed either at 3-d intervals (140–206 d), to assess reproductive development, or on the day following the first oviposition. A final group of birds was maintained for egg-production records. The ALT birds reached first egg at a younger age (220 d vs. 224 d) and lower body weight (11.18 kg vs. 11.88 kg) than CON birds did. The oviduct of the CON treatment reached its mature weight 5 d before the ovary. The growing oviduct of the ALT birds reached its mature weight 4 d after the ovary. Ovarian development of the ALT birds was accelerated by 10 d, compared with that of the CON birds. The number of unreconciled ovulations, as evidenced by postovulatory follicles at first oviposition, did not differ between treatments (1.2, ALT; 1.6, CON). The number of large follicles was not different between the two treatments (12.9, ALT; 14.3, CON [P = 0.092]). First-egg weights were significantly lower (70.6 g, ALT; 77.2 g, CON) for the ALT treatment, which also had a higher incidence of small eggs for the first 4 wk of production (3.31%, ALT; 0.82%, CON). Total egg production and total settable egg-production did not differ between treatments. Key words: Turkey, sexual maturation, lighting program, ovary, oviduct
Effects of in vitro addition of ammonia on the metabolism of 15N-labelled amino acids in isolated sheep hepatocytes
Authors: Mutsvangwa Timothy , Buchanan-Smith Jock G. , McBride Brian W.
Published: March 2010

Isolated hepatocytes prepared from sheep were used to determine the effects of added ammonia (as NH4Cl) on the flux of 15N from 15N-labelled amino acids to [14N15N]urea and [15N15N]urea. Hepatocyte suspensions were incubated with NH4Cl (0, 0.31, 0.63 and 1.25 mM) in the presence of L-[15N]alanine, L-[15N]methionine, L-[15N]leucine or L-[15N]phenylalanine (1.0 mM final concentration in the incubation media). Following 1.5 h incubation, addition of NH4Cl increased total urea and unlabelled (14N14N) urea production in all incubations (P < 0.001). Adding NH4Cl did not affect 15N isotopic enrichment of [14N15N]urea (P = 0.705) and [15N15N]urea (P = 0.204), or production of [14N15N]urea (P = 0.279) and [15N15N]urea (P = 0.708) in isolated hepatocytes incubated with [15N]alanine. Addition of NH4Cl increased [14N15N]urea production in incubations containing [15N]methionine (quadratic effect, P = 0.019), but had no effect in incubations containing [15N]leucine (P = 0.107) or [15N]phenylalanine (P = 0.135). There was no detectable production of [15N15N]urea in incubations containing [15N]methionine, [15N]leucine and [15N]phenylalanine. In all incubations, unlabelled (14N14N) urea was the predominant form of urea, indicating that isolated sheep hepatocytes can detoxify excess NH3 by channelling NH3-N into both mitochondrial carbamoyl phosphate and cytoplasmic aspartate synthesis. Key words: Sheep, liver cells, amino acids, ureagenesis, ammonia, 15N
Apparent transfer efficiency of docosahexaenoic acid from diet to milk in dairy cows
Authors: Wright T. C. , Holub B. J. , McBride B. W.
Published: March 2010

Apparent transfer efficiency of docosahexaenoic acid from diet to milk in dairy cattle was investigated. Three levels of a fish meal-containing supplement, 4.5, 14.9, and 29.1% of dry matter intake were added to a basal diet. A linear decline (from 34% to 11%) in apparent transfer efficiency was observed, as level of supplement increased. Key words: Docosahexaenoic acid, fish meal, milk composition
Melengestrol acetate, estradiol-17β and GnRH for synchronization of estrus and ovulation in beef cows
Authors: Thundathil J. , Kastelic J. P. , Olson W. O. , Cook R. B. , Mapletoft R. J.
Published: March 2010

Three experiments were conducted with suckled crossbred beef cows to determine the efficacy of various short-term regimens for synchronizing estrus or ovulation and to determine whether feeding melengestrol acetate (MGA) after timed AI will increase pregnancy rate. In exp. 1, all cows (n = 141) were given 0.5 mg MGA head−1 d−1 for 7 d (days 1 to 7), 1 or 5 mg E17β (and 100 mg progesterone) or 100 µg GnRH on day 1, and 500 µg cloprostenol on day 7. There were no significant differences among groups for estrous or synchronized conception rates (average, 84.4 and 52.1%, respectively). With an identical protocol in exp. 2 (78 cows), by day 11, cows given 5 mg E17β had the highest estrous and synchronized pregnancy rates (65.4 and 42.3%), compared to 1 mg E17β (46.2 and 15.4%) and GnRH (34.6 and 11.5%). Cows not detected in estrus were timed-inseminated and given 100 µg GnRH, 100 h after cloprostenol. There were no significant differences among groups for synchronized conception rate to timed AI (65.0%) or synchronized pregnancy rate to all inseminations (56.4%). Overall, 5 mg E17β gave the most consistent results. In exp. 3, 84 cows were given 100 µg GnRH on days 1 and 9, 500 µg cloprostenol on day 7, and were timed-inseminated on day 10. Half were fed MGA (0.5 mg head−1 d−1) on days 16 to 22, but the pregnancy rate was not different from that in the remaining cows (55.0 versus 47.8%, P > 0.5). Key words: Ovary, follicles, estrus synchronization, beef cows
Sorting feeder cattle with a system that integrates ultrasound backfat and marbling estimates with a model that maximizes feedlot profitability in value-based marketing
Authors: Basarab J. A. , Brethour J. R. , Zobell D. R. , Graham B.
Published: March 2010

Studies were conducted to evaluate a feeder cattle sorting system for tracking future carcass merit. The Kansas State University (KSU) sorting system combines initial body weight, ultrasound backfat thickness and marbling score with economic data to project the number of days on feed that will maximize profitability. The KSU sorting system was applied, 3 to 4 mo before slaughter, on 4101 yearling steers at two large feedlots located in southern Alberta. In Feedlot 1, steers averaging 408.7 kg (SD = 45.2 kg) were randomly assigned to two treatment groups: sorted by weight (control; n = 856) and sorted by the KSU sorting system (n = 849). In Feedlot 2, steers averaging 494.4 kg (SD = 42.3 kg) were randomly assigned to two treatment groups: not sorted (control; n = 798) and sorted by the KSU sorting system (n = 1598). Whole pens were marketed when the majority of steers in the pen approached the carcass weight and grade characteristics required for optimal return. The KSU sorted steers gained 0.12 kg d−1 faster at Feedlot 1 (P = 0.043) and 0.05 kg d−1 faster at Feedlot 2 (P = 0.036) than control steers. Feed intake, feed efficiency, death loss, warm carcass weight, backfat thickness, l. dorsi area, marbling score and lean meat yield were similar between sorting systems regardless of feedlot. The KSU sorting system reduced dark cutting (B4) carcasses to zero (0.0% KSU vs. 1.3% Control; P = 0.005) and increased AAA quality grade carcasses by 40.8% (31.4% KSU vs. 22.3% Control; P = 0.001) in Feedlot 1. In Feedlot 2, the KSU sorting system reduced over-fat carcasses (Y3) by 47.4% (10.2% KSU vs. 19.4% Control; P = 0.001) and increased AA carcasses by 14.7% (52.3% KSU vs. 45.6% Control; P = 0.003). These changes resulted in the KSU sorted steers being more profitable than control steers by $27.67 head−1 in Feedlot 1 and $15.22 head−1 in Feedlot 2. The increased net return was primarily due to improved weight gains and a more desirable distribution of carcass yield and quality grades. Key words: Ultrasound, carcass uniformity, steers
Beef cattle management in Manitoba
Authors: Small J. A. , McCaughey W. P.
Published: March 2010

A survey was conducted to document general characteristics of beef cattle management and identify producer concerns in Manitoba. The survey was divided into five sections: (i) characterization of farm operation, (ii) winter management, (iii) forage and pasture management, (iv) reproductive management and (v) factors limiting profitability and the use of non-traditional management tools. The surveyprovided base information for measuring change in the industry and identified cost of production, pasture, and reproduction as the top three factors that producers consider limiting the profitability of beef operations in Manitoba. Key words: Beef cattle, forage, pasture, reproduction, nutrition, survey
Effect of exogenous enzymes on digestibility of barley silage and growth performance of feedlot cattle
Authors: McAllister T. A. , Oosting S. J. , Popp J. D. , Mir Z. , Yanke L. J. , Hristov A. N. , Treacher R. J. , Cheng K.-J.
Published: March 2010

Barley silage was sprayed with water or with a 2:1 combination of commercial cellulase and xylanase preparations, or the enzymes were introduced directly into the rumen, in a digestibility study (replicated incomplete 3 × 3 Latin square) using 10 sheep. Apparent digestibilities of dry matter (DM) and neutral detergent fibre (NDF) were lower (P < 0.05) when enzymes were dosed intraruminally than when applied to silage, but enzymes by either route did not affect (P > 0.05) intake of DM, organic matter or digestible organic matter, or digestibilities of DM or NDF, ruminal pH, xylanase activity, endoglucanase activity or ruminal cellulolytic bacterial populations. Treating the silage portion of an 82.5% barley silage backgrounding diet with the enzyme mix at 0, 1.25, 3.5 or 5.0 L t−1 DM tended to linearly increase (P = 0.08) final weights of steers (n = 24). Average daily gain tended to be (P = 0.06) and feed intake and feed efficiency were (P = 0.04 and P = 0.03, respectively) quadratically related to these enzyme concentrations from days 0 to 56, but not overall (days 0 to 120). In contrast, treatment of both portions (forage and concentrate) of a 70% barley-ryegrass silage finishing diet at 3.5 L t−1 DM increased (P < 0.01) the average daily gain of finishing feedlot cattle by 10%. Carcass weights and traits were not affected (P > 0.1) by enzyme supplementation. In this study, treating the total mixed ration improved feedlot cattle performance more than treating the silage component alone. Key words: Enzymes, beef cattle, growth, barley silage
Influence of housing conditions on responses of pigs to preslaughter treatment and consequences for meat quality
Authors: Geverink N. A. , Jong I. C. de , Lambooij E. , Blokhuis H. J. , Wiegant V. M.
Published: March 2010

The effects of housing conditions on behavioural and cortisol responses during preslaughter treatment, as well as the consequences for meat quality, were studied in 48 slaughter pigs. Pigs were either raised in intensive housing conditions ("standard" treatment: standard farrowing crates (4.2 m2) followed by standard rearing pens (0.5 m2/pig) and fattening pens (0.8 m2/pig) or in extensive conditions ("enriched" treatment: larger farrowing pens (7.2 m2) followed by larger rearing and fattening pens (both 1.2 m2/pig), all provided with straw).No differences in behaviour during transport or in any of the meat quality variables were found between treatments. During pre-slaughter handling, stockmen needed significantly less time to load pigs from standard housing conditions (standard: 56.8 ± 11.9 s; enriched: 93.7 ± 12.5 s). Standard pigs may have been more motivated to leave their pens in order to explore another environment than pigs from the enriched housing pens. Rise in salivary cortisol levels due to transport (standard: 6.68 ± 0.80 ng mL−1; enriched: 3.63 ± 0.58 ng mL−1) was difficult to interpret as omission of straw during the hours prior to transport apparently led to high baseline cortisol levels in enriched pigs (8.63 ± 1.27 ng mL−1 vs. 2.60 ± 0.37 ng mL−1 in standard pigs). The extensive housing system should be preferred as it is known to have positive effects on pig welfare, and does not lead to impaired meat quality. Key words: Behaviour, housing, meat quality, physiology, pigs, slaughter
A study of growth and carcass traits in dehorned and polled composite bulls
Authors: Goonewardene L. A. , Price M. A. , Liu M. F. , Berg R. T. , Erichsen C. M.
Published: March 2010

Phenotypically dehorned (genetically horned) and polled bulls were similar for birth, weaning weight, pre- and post-weaning ADG, carcass weight, grade fat, marbling, rib-eye area, cutability and carcass grade. Polled bulls had higher (P < 0.02) fat over the rib-eye compared with dehorned. The similarity in growth and a majority of carcass traits between polled and horned, would suggest that breeding for polledness may be recommended to eliminate horns. Key words: Dehorned, polled, growth, carcass traits, bulls
Use of feed enzymes in feedlot finishing diets
Authors: Beauchemin K. A. , Rode L. M. , Karren D.
Published: March 2010

An enzyme mixture with predominantly xylanase and cellulase activities was added to a high concentrate diet (92.2%, dry matter basis) and fed to growing heifers (370 kg) reared in a commercial feedlot. Enzyme supplementation had no effect on dry matter intake but increased (P < 0.01) average daily gain by 9% (1.40 to 1.53 kg d−1) and numerically improved feed-to-gain ratio by 10% (7.72 to 6.95 kg dry matter kg−1 gain). Feed enzyme technology can improve efficiency of commercial feedlot cattle production. Key words: Beef cattle, feedlot cattle, enzymes, barley
Estimates of direct and maternal genetic parameters for weight traits and backfat thickness in a multibreed population of beef cattle
Authors: Tosh J. J. , Kemp R. A. , Ward D. R.
Published: March 2010

Variance components were estimated for weight at birth, weaning, and 365 d of age, and yearling ultrasonic backfat thickness in a multibreed population of beef cattle. Data (n = 5880) were available on F1 animals and various crosses leading up to, and including, a composite breed (7/16 British, 1/4 Charolais, 1/4 Simmental, and 1/16 Limousin). Single- and two-trait analyses were conducted using an animal model and derivative-free REML procedures. Covariates representing fractional contributions of each of the four purebred groups and average heterotic effects, both direct and maternal, accounted for breed composition. Direct and maternal genetic, maternal permanent environmental, and residual effects were the random variables. Only minor differences existed between parameter estimates obtained from the various analyses. Mean direct heritabilities were 0.51, 0.33, 0.48, and 0.37 for weight at birth, weaning, and 365-d, and backfat, respectively, which, though well within the range of published estimates, seemed higher than average, indicating diversity in the founding purebreds. Mean maternal heritabilites were 0.09, 0.13, and 0.08 for the three consecutive weights. A likelihood ratio test showed maternal heritability and(or) the direct-maternal correlation was important (P < 0.001) for 365-d weight. Averaged across weights, the direct-maternal correlation was 0.07, lacking evidence of genetic antagonism. No age of dam or random maternal effects on backfat were apparent. Phenotypic correlations between weight at birth and weaning and weight at weaning and 365-d were 0.46 and 0.76, respectively. Though moderate between birth and weaning weight, maternal genetic and permanent environmental correlations between weaning and 365-d weight approached unity, demonstrating maternal carryover effects. Phenotypic and genetic correlations of 0.19 and –0.13, respectively, implied a limited association between 365-d weight and backfat, which possibly would have been stronger had fat been measured later in life. Estimates of variance components suitable for general use can be obtained from data from multibreed animals by considering breed and heterotic effects. Key words: Beef cattle, crossbreds, genetic parameters, heritability, maternal effects
Structure of a dynamic simulation model for beef cattle production systems
Authors: Pang H. , Makarechian M. , Basarab J. A. , Berg R. T.
Published: March 2010

A dynamic deterministic model for simulating beef cattle production systems is developed to evaluate the effects of production traits and management strategies on the bioeconomic efficiency of beef production systems. The model, named Alberta Beef Production Simulation System (ABPSS), is composed of four major submodels: herd inventory, nutrient requirement, forage production, and economic submodels. The herd inventory submodel is used to simulate population dynamics and feed requirements in the herd. The nutrient requirements submodel is mainly based on the 1996 version of the National Research Council (NRC). It is used to evaluate nutrients and feed requirements for calves and cows depending on their physiological status (maintenance, growth, lactation and gestation) and the climatic condition. The forage production sub-model is used to predict forage growth rate, cattle grazing rate, available forage biomass and total hectares required for grazing. The economic submodel measures bioeconomic efficiency, as net return per cow, by subtracting total cost from total return. The nutrient requirements predicted by ABPSS were compared with those recommended by the NRC for testing. The results that were predicted by the NRC model and ABPSS model were similar, as expected. Sensitivity analyses showed that cow mature weight, milk production, calf weaning weight and feed prices were the most critical input parameters in the model. It must be noted that the model was developed based on available experimental results and data from the literature and, due to the unavailability of a suitable data set, the model could not be validated. We suggest that the ABPSS has the potential for providing a useful method for simultaneous consideration of many factors in an integrated system, which could be helpful to beef cattle extension specialists and cow-calf production managers for assessing the potential effects of different management and selection strategies on bioeconomic efficiency. Key words: Beef cattle, simulation and modelling, production system, optimization
A study on the variation of feed efficiency in station tested beef bulls
Authors: Liu M. F. , Goonewardene L. A. , Bailey D. R. C. , Basarab J. A. , Kemp R. A. , Arthur P. F. , Okine E. K. , Makarechian M.
Published: March 2010

The records of 282 young beef bulls from eight breeds tested from November 1981 to April 1987 at the Ellerslie Bull Test Station, Alberta, Canada, were used to study the variation in feed efficiency among young performance-tested bulls. Considerable variation existed among the animals in both residual metabolizable energy consumption and residual dry matter consumption. The heritability estimates for residual metabolizable energy consumption and residual dry matter consumption were 0.33 and 0.29, respectively. In addition, residual metabolizable energy consumption and residual dry matter consumption were moderately correlated (r = 0.43) with conventional feed-to-gain ratio, indicating that conventional feed-to-gain ratio only accounted for 18% of the variation in residual metabolizable energy consumption or residual dry matter consumption. It was, therefore, worthwhile to use residual metabolizable energy consumption or residual dry matter consumption as separate measures of feed efficiency. For rapid improvement in feed efficiency in beef cattle, selection pressure should be applied to both growth traits and residual energy consumption or residual dry matter consumption. Multi-trait optimum restricted selection indices and similar selection procedures may serve as useful means in balanced selection programs to improve the productivity of beef cattle. Key words: Feed efficiency, residual ME consumption, beef bulls
Genetic analysis of velvet antler yield in farmed elk (Cervus elaphus)
Authors: Wang Z. , Yang R -C. , Goonewardene L. A. , Huedepoh C.
Published: March 2010

Data from the Alberta Agriculture Food and Rural Development data base, which keeps inventories of elk producers and velvet production information (n = 12 724), were used to estimate genetic and phenotypic variances, heritability and repeatability estimates for velvet antler using REML methods. The heritability based on the animal models I and II was 0.27 ± 0.03 and the repeatability ranged from 0.31 ± 0.02 to 0.35 ± 0.03 depending on the animal model used. Antler yield is expected to respond to selection as the heritability is medium, but non-additive and environmental effects can also influence production. Key words: Elk, heritability, repeatability, antler production
Response of serum concentrations of folates to dietary supplements of folic acid given to ewes during gestation
Authors: Girard C. L. , Castonguay F. , Matte J. J.
Published: March 2010

Serum folates were determined during the 24 h following the ingestion of 0, 130, 260 or 520 mg of folic acid at 12, 61 and 131 d of gestation in 38 ewes. The response of serum folates increased with the dose ingested (P < 0.0001) but decreased as gestation progressed (P < 0.005). Key words: Ewe, dietary supplements, folic acid, vitamin B12
Effects of feeding canola screenings on apparent digestibility, growth performance and carcass characteristics of feedlot lambs
Authors: Stanford K. , Wallins G. L. , Smart W. G. , McAllister T. A.
Published: March 2010

Commercial coarse canola screenings (CS) were substituted for barley grain, and the resulting experimental diets (0, 20, 45, 70 and 95% CS, as-fed) were evaluated in feedlot lambs, while the 0, 45 and 95% CS diets were evaluated in a digestibility study using Romanov × Suffolk lambs. The CS comprised 60% canola (as whole, broken and immature seeds), 25% weed seeds and 15% chaff/dust. The control diet (0% CS) contained 75% barley and 20% alfalfa (as a protein/fibre source). Dietary crude protein (CP) increased with inclusion of CS and was lowest for control and 20% CS diets (13%) and highest for the 95% CS diet (14.4%). Digestibilities of dry matter (DM), organic matter (OM), neutral detergent fibre (NDF) and acid detergent fibre (ADF) were reduced (P < 0.05) in the 95% diet as compared with the control diet. Nitrogen retention by lambs was three times higher in the control group than in the 95% CS group (P < 0.001). Growth and feed conversion efficiency in feedlot lambs were linearly reduced (P < 0.001) with increasing dietary CS, but so was saturation of carcass fat (P < 0.001), which may benefit human health. Reduced lamb performance with CS was likely related to its high contents of crude fat (9%, DM basis) and ash (14%, DM basis). Valuing CS at 86% of the cost of barley, incorporation of up to 45% CS in feeder lamb diets would be cost effective. Key words: Canola, by-product, screenings, lamb, growth, carcass
Carcass evaluation of cattle finished on alfalfa/grass pastures alone or supplemented with barley
Authors: McCaughey W. P. , McAllister T. A. , Popp J. D. , Shelford J. A. , Cheng K-J.
Published: March 2010

Yearling cattle fed pasture-only for the entire grazing season were compared with cattle receiving pasture plus steam-rolled barley (SRB; 4 kg head−1 d−1) or pasture plus SRB (4 kg head−1 d−1) treated with Tween 80 at a rate of 4 kg t−1, for 74 d prior to slaughter. Heifers were more likely (P = 0.015) to grade A or higher than steers. Feeding supplemental grain on pasture increased pasture gains (P < 0.001) and hot carcass weight (P < 0.001) but did not (P > 0.05) improve carcass quality, chemical analysis, shear force, carcass value or gross return per head. Treatment of SRB with Tween-80 did not influence (P > 0.05) cattle performance or carcass quality. From the results reported in this study, it is possible to finish cattle on pasture to Canada A grade standards. Key words: Forage-finishing, carcass quality, beef, pasture, grain
Effects of a beta-adrenergic agonist (L-644,969) on performance and carcass traits of growing lambs in a cold environment
Authors: Li Y. Z. , Christopherson R. J. , Li B. T. , Moibi J. A.
Published: March 2010

A 2 × 2 factorial experiment was conducted to study the effects of the beta-adrenergic agonist L-644,969 (BAA, supplied at 0.28 vs. 0 mg kg−0.75 d−1) on growth performance, carcass traits and nitrogen balance of lambs at two environmental temperatures (0°C vs. 20 °C). Sixteen Suffolk-Cross wether lambs (30.2 ± 2.06 kg BW) were randomly divided into four groups and exposed to each of four experimental treatments (20 °C with control diet; 20 °C with BAA-supplemented diet; 0 °C with control diet; and 0 °C with BAA-supplemented diet) for 5 wk. The collection period for nitrogen balance was 4 d during the 4th week of treatment. The low temperature decreased efficiency of feed utilization and increased backfat thickness by 20.8% (P < 0.01) and 35.1% (P < 0.05), respectively. L-644,969, on the other hand, increased daily gain, feed efficiency and hot carcass weight by 22.5% (P < 0.05), 17.2% (P < 0.05) and 9.6% (P < 0.05,) respectively. Dressing percentage (P < 0.01), biceps femoris weight (P < 0.01) and rib eye area (P < 0.01) were also increased, but abdominal fat expressed as a percentage of liveweight (P < 0.05) was significantly decreased by BAA treatment. The improved weight gain, muscle weight and ribeye area in response to BAA, and in the absence of an increase in total nitrogen retention, indicate that the responses are due to nutrient repartitioning. Temperature did not impair the nutrient repartitioning effect of BAA, but feed efficiency may be more improved by BAA for the animals in the cold environment. Key words: Performance, carcass traits, beta-agonist, temperature, lambs
Behavioural indicators of cow comfort: activity and resting behaviour of dairy cows in two types of housing
Authors: Haley D. B. , Rushen J. , Passillé A. M. de
Published: March 2010

We explored which aspects of dairy cow behaviour provide measures of cow comfort and how housing affects resting time. Following a crossover design, we observed the behaviour of eight lactating Holstein cows kept for three weeks in stalls believed to represent a contrast in comfort. Cows individually housed in large pens with a mattress flooring lay down 4.2 h d−1 longer than cows housed in tie-stalls on a concrete floor, while cows in tie-stalls stood idle (without eating) for longer. Cows stood up and lay down more often in the large pens and the duration of individual standing bouts was longer in tie-stalls. We found no differences in eating time and few differences in body, head or leg positions cows assumed while lying. There was little evidence of diurnal rhythm in activity. A lower frequency of standing and lying and an increase in the duration of lying bouts suggests that in tie-stalls cows are more reluctant to change position from lying to standing. The type of pen or stall in which cows are housed can have a substantial impact on resting time. The duration and frequency of lying behaviour and the time spent standing without eating appear to be probable behavioural indicators of cow comfort. Key words: Behaviour, cow comfort, housing, lying, resting
Effects of social stress on heart rate and heart rate variability in growing pigs
Authors: Jong I. C. de , Sgoifo A. , Lambooij E. , Korte S. M. , Blokhuis H. J. , Koolhaas J. M.
Published: March 2010

The effects of social stress on heart rate, heart rate variability and the occurrence of cardiac arrhythmias were studied in 12 growing pigs. Social stress was induced during a good competition test with a pen mate, and subsequently during a resident–intruder test with an unacquainted pig in which the experimental pig was the intruder. The outcome of a test was determined using observations of agonistic behaviour. Five pigs won the food competition test. All pigs were defeated in the resident–intruder test with an unacquainted pig. For all pigs, heart rate was significantly higher and thus the R-R interval significantly lower during the food competition test and resident–intruder test than during baseline recordings. However, pigs that were first defeated in the food competition test had a higher heart rate during the first 7 min of the resident–intruder test than winners of the food competition test. Parameters of heart rate variabiality did not significantly change during the food competition test and the resident–intruder test relative to baseline recordings. Thus, the parasympathetic and the sympathetic nervous system remained in balance during the social stress situations. This may explain why the occurrence of cardiac arrhythmias did not increase during the food competition test and the resident–intruder test relative to baseline. We showed that social status, based on agonistic encounters during the food competition test, may influence the heart rate responses of pigs during the resident–intruder test. When heart rate is used as an index of stress, results indicate that subordinate pigs may experience more stress during an agonistic encounter with an unacquainted pig than dominant pigs. Key words: Behaviour, heart rate, social stress, telemetry, pigs
An examination of fertility, hatchability, embryo mortality, and chick weight in double versus single-yolked broiler breeder eggs
Authors: Fasenko G. M. , Robinson F. E. , Danforth B. L. , Zelter I.
Published: March 2010

The objective of this study was to document the fertility and embryonic mortality problems that result in the poor hatchability of double yolk (DY) versus (single yolk) SY broiler breeder eggs. Both SY (n = 64) and DY (n = 141) eggs were collected from a commercial Hubbard Hi-Y flock and the eggs incubated for 21 d. All eggs were candled and weighed at 7, 14 and 18 d, and any non-viable eggs were removed and broken open to assess fertility, and if fertile, stage of embryonic death. Any unhatched eggs remaining after 21 d of incubation were broken open so that fertility, hatchability and embryo mortality could be calculated. Because there is the potential for two chicks to hatch from a DY egg, fertility, hatchability, and embryo mortality were calculated on a per yolk basis rather than an egg basis. Fertility, hatchability, and hatchability of fertile eggs were significantly lower (P < 0.05) in DY compared to SY eggs. Early- (≤7 d of incubation), mid (8–14 d of incubation), and late (≥15 d of incubation) embryonic mortality was significantly higher in DY vs. SY eggs. Chick body weights were significantly greater in solitary chicks hatching from DY eggs versus chicks hatching from SY eggs. Key words: Double yolk, embryo mortality, broiler breeders, chick weight, hatchability, fertility
Food safety and the consumer – perils of poor risk communication
Authors: Powell Douglas A.
Published: March 2010

The potential for stigmatisation of food is enormous. Well-publicised outbreaks of foodborne pathogens and the furore over agricultural biotechnology are but two current examples of the interactions between science, policy and public perception. Current risk management research indicates that it is essential for risk managers to show that they are reducing, mitigating or minimising a particular risk. Those responsible must be able to effectively communicate their efforts and must be able to prove they are actually reducing levels of risk.The components for managing the stigma associated with any food safety issue involve the following factors:• effective and rapid surveillance systems;• effective communication about the nature of risk;• a credible, open and responsive regulatory system;• demonstrable efforts to reduce levels of uncertainty and risk; and,• evidence that actions match words.Appropriate risk management strategies, such as on-farm food safety programs, are essential to demonstrate to consumers and others in the farm-to-fork supply chain that producers and regulators are cognisant of their concerns about food safety. Key words: Agricultural biotechnology, microbial food safety, genetically engineered food, risk perception, risk communication, risk management
Comparative efficiency of various fats rich in medium-chain fatty acids to suppress ruminal methanogenesis as measured with RUSITEC
Authors: Dohme F. , Machmüller A. , Wasserfallen A. , Kreuzer M.
Published: March 2010

A RUSITEC apparatus equipped with eight fermenters was used to investigate the effects of seven different fats with high proportions of medium-chain fatty acids (C8:0–C16:0) supplied at a level of 53 g kg−1 DM. In detail, coconut oil, palm kernel oil, palm oil, tallow, milk fat and two types of canola oils, both genetically enriched with lauric acid, were compared with a diet supplemented with prilled fat. The prilled fat was selected from three different rumen-protected fats in a preliminary experiment as the least effective one regarding methane release. Palm kernel oil, coconut oil and one of the canola oils significantly (P < 0.05) decreased methane release, methanogens and ciliates whereas the other fats had only minor effects. With the use of the three effective fats, NDF degradation was also suppressed (P < 0.05), but the rumen fluid concentration of volatile fatty acids remained unchanged. However, at constant acetate proportion, butyrate proportion increased (P < 0.05) at the expense of propionate. Apart from a high proportion of lauric and myristic fatty acids in the fatty acid composition, complete melting at rumen fluid temperature seems to support the ability of some fats to reduce methanogenesis and to suppress methanogens and ciliates. Key words: Methane, fats, medium-chain fatty acids, laurate canola, fermentation, ruminants
Effects of increasing dietary grain on viscosity of duodenal digesta and plasma hormone, glucose and amino acid concentrations in steers
Authors: Mir P. S. , Mears G. J. , Okine E. K. , Entz T. , Ross C. M. , Husar S. D. , Mir Z.
Published: March 2010

Effects of increasing the proportions of dietary barley grain or corn on viscosity of duodenal digesta supernatant and concentrations of cholecystokinin (CCK), glucose and amino acids in portal plasma and concentrations of CCK, insulin and glucose in jugular plasma were determined. Four steers (374 ± 6.4 kg) were surgically fitted with ruminal and duodenal cannulae and indwelling portal vein catheters. The steers were fed diets containing 20, 40, 60, and 80% rolled barley or cracked corn (DM basis) replacing respective silages, in two experiments with 4 × 4 Latin square design. After adjusting the steers to the diets for 14 d, digesta samples from the duodenum and blood samples from the portal and jugular veins were collected twice daily for 5 d. Increasing the proportion of dietary barley or corn increased the viscosity [measured as centipoise (cP)] of duodenal supernatant (from 1.3 to 2.0 and from 1.5 to 2.8 cP, P < 0.05), respectively. Portal plasma CCK concentration increased linearly (2.4 to 4.9 pmol, P < 0.05) as the proportion of dietary barley increased. However, in corn-fed steers, the highest portal CCK concentrations were observed in steers receiving 20% corn and these concentrations were not affected by corn content of the diet. Increasing dietary barley resulted in a linear increase in jugular plasma CCK concentration of steers, but a linear (P < 0.05) decline was noted when corn was fed to steers in increasing proportions. Portal and jugular plasma glucose concentrations were not altered in barley-fed steers, but both portal and jugular glucose increased (P < 0.05) with increasing dietary corn. Jugular insulin concentration was higher in steers fed 80% barley or corn than in those receiving the diets with less grain. Total amino acid concentrations in portal plasma were higher by 30% in steers fed corn than in those fed barley, but were not affected by relative proportion of dietary corn. These data suggest that feeding cattle increasing proportions of barley or corn grain increases duodenal viscosity, which, together with components of digesta, may be involved in affecting the secretion of hormones, such as CCK, and the concentrations of absorbed nutrients in portal plasma, which can be expected to influence animal performance. Key words: Steers, dietary barley, corn, portal and jugular hormones, glucose, amino acids
Efficacy of chemical castration and effects of age at castration and implant regime on growth rate, testicular measurements and testosterone levels of beef calves
Authors: Cohen R. D. H. , King B. D. , Hunter P. S. W. , Janzen E. D.
Published: March 2010

In 1984–1985 and 1985–1986, groups of 136 and 127 male calves were used to assess the effects of multiple implants (Ralgro or Steeroid), castration time (early or late) and castration method (surgical or chemical) on testicular development and weight gain for 28 d following castration. Ralgro-implanted bull calves had smaller scrotal circumference (P < 0.001) and testicle weight (P < 0.001) than nonimplanted calves at early castration (59 ± 1 d), late castration (157 ± 1 d) and at slaughter (459 ± 3 d). Steeroid had no effect on testicle weight at early castration (40 ± 1 d) but reduced testicle weight (P < 0.001) at late castration (148 ± 1 d). Average daily gain (ADG) during the first 7 d postcastration was less for surgically castrated than chemically castrated calves or bulls following early castration (P < 0.05) but in the 7 d following late castration, bull calves grew faster than surgical castrates (P < 0.05) and surgical castrates grew faster than chemical castrates (P < 0.05). The ADG of calves implanted with Ralgro was greater than that of nonimplanted calves during the 28-d period following early and late castration (P < 0.05) but Steeroid had no effect (P > 0.05) on 28-d postcastration ADG. Chemical castration increased scrotal circumference at 7, 14 and 28 d postcastration (P < 0.001) but by day 56, testicular atrophy was complete in those calves that were successfully castrated. Chem-cast was an effective method of castration in young calves (< 90 kg liveweight), particularly those that had been implanted with Ralgro, but efficacy was reduced (P < 0.05) in older calves (> 150 kg liveweight). Key words: Castration, Chem-cast, Ralgro, Steeroid, testosterone, beef
Follicular dynamics, corpus luteum growth and regression in lactating dairy cattle
Authors: Taylor C. , Rajamahendran R.
Published: March 2010

Ultrasound imaging and progesterone (P4) profiles were used to characterize follicular and corpus luteum (CL) growth and regression in 10 cycling dairy cows. Thirteen of sixteen cycles were characterized by two waves of follicular growth, the second wave giving rise to the ovulatory follicle. The remaining three cycles had three waves. There was no difference between two- and three-wave cycles with regard to the day of emergence of the first or second dominant follicle (day 2.5 ± 0.9 vs. day 2.4 ± 1.2 and day 12.4 ± 1.6 vs. day 12.0 ± 2.0, respectively) or the onset of regression of the first dominant follicle (day 12.5 ± 1.5 vs. day 12.3 ± 1.5). In two wave cycles, estrous cycle length was shorter (20.8 ± 1.7 d vs. 29.7 ± 4.9 d), the first day of decline in P4 (day 16.2 ± 1.5 vs. day 23.7 ± 5.5) and the onset of CL regression (day 17.1 ± 1.3 vs. day 24.3 ± 5.5) was earlier. It is concluded that two waves of follicular growth in an estrous cycle is the norm in lactating dairy cows. The presence of an additional wave is due to a prolonged luteal phase. Key words: Follicle, corpus luteum, estrous cycle, dairy cow
Use of a semicontinuous culture system (RUSITEC) to study the metabolism of ethanol in the rumen and its effects on ruminal digestion
Authors: Durix Andrée , Jean-Blain C. , Sallmann H. P. , Jouany J. P.
Published: March 2010

The metabolism of ethanol by rumen micro-organisms and its effects on rumen fermentations have been studied in vitro in a semicontinuous fermentor (RUSITEC). Ethanol introduced in the fermentor at 1, 4 or 8 g d−1 L−1 of rumen juice induced important qualitative and quantitative modifications in the fermentation outputs. Total VFA production was increased from 5 to 40% according to the diet and ethanol concentration. Relative proportions of VFA were modified: caproate concentration increased three times, propionate and isovalerate concentrations decreased significantly in most cases. Methane production was increased. Whatever the ethanol concentration and the type of diet, in vitro digestibility parameters and end-products from solid feedstuffs stayed practically unchanged by ethanol addition. Except with the lowest supply (1 g d−1 L−1), ethanol induced an uncoupling effect on the metabolism of rumen bacteria and decreased biomass production. Radioactivity of 2-14C ethanol was recovered mainly in acetate (77–80%). Microbial transformation of ethanol in RUSITEC was limited regardless of ethanol concentration. Ethanol had a negligible effect on the digestibility of solid feedstuffs but induced consistent qualitative changes in rumen fermentations. Key word: Ethanol, metabolism, rumen, semicontinuous culture