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The School of Animal Sciences merged Dairy Science and Animal and Poultry Science in 2022.
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- Turkey sperm mobility influences paternity in the context of competitive fertilizationSmith, Edward J. (1999-01-01)
- Nutrient recycling: The North American experience - ReviewFontenot, Joseph P. (1999-06)Options available for utilization of animal wastes include sources of plant nutrients, feed ingredients for farm animals, substrate for methane generation, and substrate for microbial and insect protein synthesis. The wastes have the most economic value for use as animal feed. Performance of animals fed diets containing animal wastes is similar to that of animals fed conventional diets. Processing of animal wastes to be used as animal feed is necessary for destruction of pathogens, improvement of handling and storage characteristics, and maintenance or enhancement of palatability. Feeding of animal waste has not adversely affected the quality and taste of animal products. In the USA copper toxicity has been reported in sheep fed high-copper poultry litter, but this is not a serious problem with cattle. Potential pathogenic microorganisms in animal wastes are destroyed by processing such as heat treatment, ensiling and deep stacking. Incidents of botulism, caused by Clostridium botulinum, have been reported in cattle in some countries, and this problem was caused by the presence of poultry carcasses in litter. This problem has not occurred in the USA. With appropriate withdrawal, heavy metal, pesticide or medicinal drug accumulation in edible tissues of animals fed animal wastes is not a problem. Feeding of animal wastes is regulated by individual states in the USA. The practice is regulated in Canada, also. With good management, animal wastes can be used safely as animal feed.
- Estimation of additive, dominance and epistatic variance components using finite locus models implemented with a single-site Gibbs and a descent graph samplerDu, F. X.; Hoeschele, Ina (Cambridge University Press, 2000-10)In a previous contribution, we implemented a finite locus model (FLM) for estimating additive and dominance genetic variances via a Bayesian method and a single-site Gibbs sampler. We observed a dependency of dominance variance estimates on locus number in the analysis FLM. Here, we extended the FLM to include two-locus epistasis and implemented the analysis with two genotype samplers (Gibbs and descent graph) and three different priors for genetic effects (uniform and variable across loci, uniform and constant across loci, and normal). Phenotypic data were simulated for two pedigrees with 6300 and 12300 individuals in closed populations, using several different, non-additive genetic models. Replications of these data were analysed with FLMs differing in the number of loci. Simulation results indicate that the dependency of non-additive genetic variance estimates on locus number persisted in all implementation strategies we investigated. However, this dependency was considerably diminished with normal priors for genetic effects as compared with uniform priors (constant or variable across loci). Descent graph sampling of genotypes modestly improved variance components estimation compared with Gibbs sampling. Moreover, a larger pedigree produced considerably better variance components estimation, suggesting this dependency might originate from data insufficiency. As the FLM represents an appealing alternative to the infinitesimal model for genetic parameter estimation and for inclusion of polygenic background variation in QTL mapping analyses. further improvements are warranted and might be achieved via improvement of the sampler or treatment of the number of loci as an unknown.
- Virginia cow herd performance check-upMcKinnon, Bill R.; Hall, John B.; Covey, Thomas W.; Greiner, Scott P. (Virginia Cooperative Extension, 2001)
- Virginia 4-H Ewe Flock Project GuideWahlberg, Mark L.; Greiner, Scott P. (Virginia Cooperative Extension, 2001)A project designed to assist the 4-H member in developing characteristics of responsibility and sound decision-making while acquainting them with general care and maintenance of a sheep flock.
- Bayesian QTL mapping using skewed Student-tdistributionsvon Rohr, Peter; Hoeschele, Ina (2002-01-15)In most QTL mapping studies, phenotypes are assumed to follow normal distributions. Deviations from this assumption may lead to detection of false positive QTL. To improve the robustness of Bayesian QTL mapping methods, the normal distribution for residuals is replaced with a skewed Student-t distribution. The latter distribution is able to account for both heavy tails and skewness, and both components are each controlled by a single parameter. The Bayesian QTL mapping method using a skewed Student-t distribution is evaluated with simulated data sets under five different scenarios of residual error distributions and QTL effects.
- Effects of load type (pollen or nectar) and load mass on hovering metabolic rate and mechanical power output in the honey bee Apis melliferaFeuerbacher, Erica N.; Fewell, Jennifer H.; Roberts, Stephen P.; Smith, Elizabeth F.; Harrison, Jon F. (2003)In this study we tested the effect of pollen and nectar loading on metabolic rate (in mW) and wingbeat frequency during hovering, and also examined the effect of pollen loading on wing kinematics and mechanical power output. Pollen foragers had hovering metabolic rates approximately 10% higher than nectar foragers, regardless of the amount of load carried. Pollen foragers also had a more horizontal body position and higher inclination of stroke plane than measured previously for honey bees (probably nectar foragers). Thorax temperatures ranked pollen > nectar > water foragers, and higher flight metabolic rate could explain the higher thorax temperature of pollen foragers. Load mass did not affect hovering metabolic rate or wingbeat frequency in a regression-model experiment. However, using an analysis of variance (ANOVA) design, loaded pollen and nectar foragers (mean loads 27% and 40% of body mass, respectively) significantly increased metabolic rate by 6%. Mean pollen loads of 18% of body mass had no effect on wingbeat frequency, stroke amplitude, body angle or inclination of stroke plane, but increased the calculated mechanical power output by 16–18% (depending on the method of estimating drag). A rise in lift coefficient as bees carry loads without increasing wingbeat frequency or stroke amplitude (and only minimal increases in metabolic rate) suggests an increased use of unsteady power-generating mechanisms.
- Digestion and nitrogen utilization by sheep fed diets supplemented with processed broiler litterKwak, W. S.; Fontenot, Joseph P.; Herbein, J. H. (2003-11)In vivo digestion and metabolism trials were conducted with 10 wethers equipped with ruminal, abomasal, and ileal cannulae to evaluate digestion of ensiled broiler litter (EBL), deepstacked broiler litter (DBL), and composted broiler litter (CBL). Wethers were fed a low protein (6.3% CP) basal diet alone or supplemented to 10.3% CP with EBL, DBL, CBL or soybean meal (SBM). All diets were formulated to be isoenergetic (56% TDN, DM basis). Apparent digestibilities of DM, OM, and ADF were not affected (p<0.05) by diet, but digestibility of CP was improved (p<0.05) by N supplementation. Apparent digestibility of CP was lower (p<0.05) for diets supplemented with CBL and DBL than for diets supplemented with SBM and EBL. Ruminal NH(3) concentration was 20 to 24 mg/dl at 2 h after feeding litter-supplemented diets compared with 13 mg/dl for SBM. Abomasal N, NH3 N, and nonammonia N flows were increased (p<0.05) by N supplementation, whereas microbial N flow was not influenced (p<0.05) by diet. Compared with SBM and EBL, undegraded dietary CP flow to the abomasum tended to be greater (p<0.1) when wethers were fed DBL and CBL-supplemented diets. Retention of N (g/d) also was greater (p<0.05) due to greater (p<0.05) N intake and lower (p<0.05) urinary N excretion when wethers were fed diets supplemented with litter (especially EBL) vs. SBM. Overall, characteristics of ruminal fermentation and digestion indicated that broiler litter N was utilized efficiently by wethers, but ensiling may be preferable to deepstacking or composting.
- Effects of dietary cis 9, trans 11-18 : 2, trans 10, cis 12-18 : 2 or vaccenic acid (trans 11-18 : 1) during lactation on body composition, tissue fatty acid profiles, and litter growth in miceLoor, J. J.; Lin, X. B.; Herbein, J. H. (Cambridge University Press, 2003-12)Cis 9, trans 11 (c9, t11)-18:2 and trans 10, cis 12 (t10, c12)-18:2 are the major conjugated linoleic acid (CLA) isomers in dietary supplements which reduce milk fat content in nursing women. The present study evaluated the effects of each CLA isomer or vaccenic acid on body composition and tissue fatty acids during lactation in mice. Dams were fed 30 g rapeseed oil (control)/kg diet or 20 g control plus 10 g 18: 0, trans 11-18: 1 (t11-18 : 1), c 9, t1 1-18: 2, or t10, c12-18: 2. Dietary t10, c12-18: 2 reduced food intake by 18 % and carcass fat weight of the dams by 49 % compared with the other treatments. Milk fat percentage ranked by treatment was 18: 0 > t1 1-18: 1 = c 9, t11-18:2 > t10, c12-18:2. The sum of saturated 12:0 to 16:0 in milk fat was lower when c9, t11-18:2 was fed compared with the control, 18:0, or t11-18: 1 treatments. Dietary t10, c12-18:2 caused further reductions in milk fat 12:0 to 16:0. The proportion of CLA isomers was 3-fold greater in milk fat than in the carcasses of the dams. The pups nursing from the dams fed t10, c12-18:2 had the lowest body weights and carcass fat, protein, and ash contents. Nursing from the dams fed c9, t1 l-18:2 also resulted in lower carcass fat compared with the 18:0 or t1 l-18 : 1 treatments. The ratios of cis 9-16: 1:16:0 or cis 9-18: 1:18:0, proxies for Delta(9)-desaturase activity, were markedly lower in the carcasses of the dams and pups fed t10, c12-18: 2. The ratio of 20: 4n-6:18: 2n-6, a proxy for Delta(6)- and Delta(5)-desaturase and elongase activity, in the liver of the dams and pups fed t10, c12-18: 2 also was lower. Dietary t1 l-18 : 1 enhanced the content of c9, t1 l-18 : 2 in milk fat and carcasses. As in previous studies, the reduction in food intake by t10, c12-18: 2 could not entirely account for the marked decrease in carcass fat content and milk fat concentration. T10, c12-18: 2 probably had a negative effect on Delta(9)-desaturase and mammary de novo fatty acid synthesis. Although these effects need to be confirmed in lactating women, the results suggest that the consumption of supplements containing t10, c12-18: 2 should be avoided during the nursing period.
- Dietary phosphorus effects on characteristics of mechanically separated dairy manureKnowlton, Katharine F.; Love, Nancy G.; Parsons, C. A. (American Society of Agricultural and Biological Engineers, 2005)One approach to reduce nutrient losses from livestock farms is to apply biological waste treatment systems such as biological nitrogen (N) removal or enhanced biological phosphorus (P) removal (EBPR) to reduce the nutrient content of land-applied waste. The EBPR process takes advantage of the ability of P-accumulating organisms (PAOs) to sequester excess P as polyphosphate granules in their cytoplasms, yielding a P-depleted liquid effluent and a P-enriched biomass. Biological N removal systems result in the conversion of organic or ammonia-N to innocuous N-2 gas. Understanding the variation in parameters such as chemical oxygen demand (COD), total and volatile suspended solids (TSS and VSS), and ammonia-N (NH3-N) is necessary to design these systems. Our objectives were to evaluate the effects of diet and manure separation on parameters important to reactor design. Waste was collected from nine cows fed a high P diet (0.47% P), a low P diet (0.32 % P), or low P with exogenous phytase plus cellulase (0.32 % P), in a replicated Latin square design (three 3 X 3 squares). Total collection of milk, urine, and feces was conducted on days 19 to 21 of each period, a mixed slurry (urine, feces, and water) was created, and slurry was separated mechanically to generate liquid effluent. Slurry contained more COD, solids, N, and P than liquid effluent, but the COD:P ratio was similar in the two wastes. The ratio of COD:N was higher in slurry than in separator effluent, but the ratio in both wastes was sufficient to support biological N removal. The P content of slurry, liquid effluent, and manure solids from cows fed low P was lower than from cows fed high P, and the COD content of effluent was higher with the low P diet. The COD:P ratio of all wastes was sufficient to support EBPR and biological N removal, but variation was observed with diet. Waste from cows fed low P had a higher COD:P ratio than that of cows fed high P, and waste from cows fed the enzyme-supplemented diet had a lower COD:N ration than that of cows fed the control diet. Dairy manure slurry and effluent will support EBPR and biological N removal. Dietary effects on parameters important to the design of advanced waste treatment systems were observed, but were not of a magnitude that would affect reactor design.
- Poultry genomics puts meat on the tableSmith, Edward J.; Pourquié, Olivier; Burt, David W. (2005)Why did the chicken cross the road, you ask? Because the draft sequence of its genome has been released, silly. So, along with other ‘bird enthusiasts’ and advocates, those long involved in chicken genetics and genetic studies of birds came to Cold Spring Harbor Laboratory (CSHL), 8–11 May 2005, for the 3rd Chicken Genomics Workshop to pat each other on the back for the recently released draft sequence (International Chicken Genome Sequencing Consortium, 2004), compare notes, review progress, and plan for the road ahead! Never mind that the meeting preceded, perhaps as a convenience or, to a cynic, just ‘being chicken’ (an inability to ‘stand alone’?), the annual ‘Biology of Genomes’ meeting: these scientists did not shy away from the ‘chicken jokes’ or from making a strong case for why their work ranks up there with other tractable biomedical models. Joking aside, many speakers at the chicken meeting also attended or were part of ‘Biology of Genomes’, so the chicken is now clearly recognized as a model genome and of great value in evolutionary comparisons. Scientific presentations included the usual staples at genome meetings, such as SNPs, sequence to function, QTL identification and expression profiling. They also included novel talks about gynandromorphs, endogenous viral elements, transgenesis, developmental mutants and signalling pathways. The gathering represented a culmination and a celebration of a vision that started with the partnership between Jerry Dodgson, Michigan State, and Lyman Crittenden, USDA–ARS, as well as the efforts of several European scientists, including the late Nat Bumstead, Martien Groenen (Wageningen) and Dave Burt (Roslin Institute). It was appropriate that the meeting ended with an exploration by the chicken community of ‘what now?
- Characterization of Expressed Sequence Tags From a Gallus gallus Pineal Gland cDNA LibraryHartman, Stefanie; Touchton, Greg; Wynn, Jessica; Geng, Tuoyu; Chong, Nelson W.; Smith, Edward J. (Hindawi, 2005-01-01)The pineal gland is the circadian oscillator in the chicken, regulating diversefunctions ranging from egg laying to feeding. Here, we describe the isolation andcharacterization of expressed sequence tags (ESTs) isolated from a chicken pinealgland cDNA library. A total of 192 unique sequences were analysed and submittedto GenBank; 6% of the ESTs matched neither GenBank cDNA sequences nor thenewly assembled chicken genomic DNA sequence, three ESTs aligned with sequencesdesignated to be on the Z_random, while one matched a W chromosome sequence andcould be useful in cataloguing functionally important genes on this sex chromosome.Additionally, single nucleotide polymorphisms (SNPs) were identified and validatedin 10 ESTs that showed 98% or higher sequence similarity to known chicken genes.Here, we have described resources that may be useful in comparative and functionalgenomic analysis of genes expressed in an important organ, the pineal gland, in amodel and agriculturally important organism.
- Genistein activates the 3 ',5 '-cyclic adenosine monophosphate signaling pathway in vascular endothelial cells and protects endothelial barrier functionLiu, Dongmin; Jiang, Honglin; Grange, Robert W. (Endocrine Society, 2005-03)The soy phytoestrogen, genistein, has an array of biological actions, including weak estrogenic effects, inhibition of tyrosine kinase, and cellular antioxidant activity. Recent studies showed that genistein may improve vascular function, but the mechanism is unclear. We show that genistein stimulates intracellular cAMP accumulation in intact bovine aortic endothelial cells and human umbilical vein endothelial cells over an incubation period of 30 min. Increases in intracellular cAMP are evoked by as low as 10 nM genistein but not by estrogen. These increases in cAMP may result primarily from enhanced adenylate cyclase activity by a mechanism that does not involve genomic actions or estrogen receptors. The cAMP induced by genistein activates cAMP-dependent protein kinase (PKA) in bovine aortic endothelial cells. The activation of PKA phosphorylates and activates cAMP response element binding protein, leading to up-regulation of cAMP response element-containing gene expression. In addition, activation of PKA protects thrombin-induced endothelial monolayer permeability, a novel cardioprotective effect of genistein mediated by the cAMP/PKA cascade. These findings demonstrate that a nongenomic action of genistein leads to activation of the cAMP/PKA signaling system to protect the vascular barrier function and alter the expression of cAMP-regulated genes, thereby providing a novel mechanism underlying some of the cardiovascular protective effects proposed for soy phytoestrogens.
- Virginia Cow Herd Performance Check-UpMcKinnon, Bill R.; Hall, John B.; Covey, Thomas W.; Greiner, Scott P. (Virginia Cooperative Extension, 2005-09-01)An annual analysis of various herd performance measures can serve as a yardstick against which to compare past and future years' performance.
- Cattle Identification: Freeze BrandingHall, John B.; Greiner, Scott P.; Gregg, Cynthia L. (Virginia Cooperative Extension, 2005-09-01)Freeze branding offers a permanent form of individual animal identification that is easy to read at a great distance, causes minimal damage to the hide, and is less painful than hot branding.
- Understanding Expected Progeny Differences (EPDs)Greiner, Scott P. (Virginia Cooperative Extension, 2005-09-01)Expected progeny differences (EPDs) provide estimates of the genetic value of an animal as a parent, and should be given careful attention when choosing bulls.
- Crossbreeding Beef CattleGreiner, Scott P. (Virginia Cooperative Extension, 2005-09-01)A well-designed, manageable crossbreeding system is an important aspect in making genetic progress in the various economically important traits that drive profitability in today's beef industry.
- Beef Cattle Breeds and Biological TypesGreiner, Scott P. (Virginia Cooperative Extension, 2005-09-01)There are more than 250 breeds of beef cattle. The breed, or combination of breeds, used in a defined breeding program have a significant impact on the efficiency and profitability of the beef enterprise.
- Use of N-alkanes to estimate intake and digestibility by beef steersPrernaratne, Sameera; Fontenot, Joseph P.; Shanklin, R. K. (2005-11)The objective of the study was to evaluate the use of n-alkanes to estimate DM intake and digestibility by beef cattle. Six steers were blocked (3 blocks, 2 animals/block) according to the body weight (279 +/- 19 kg) and randomly allotted within blocks to two diets (3 steers/diet). A second trial was conducted with the same animals (321 +/- 18 kg) after 36 days (d), using a switch back design. The diets consisted of two types of chopped sun-cured hay, alfalfa (Medicago sativa L) hay, or fescue (Festuca arundinacea Schreb) and alfalfa mixture, which were fed in equal amounts to steers. Animals were dosed with C-32 and C-36 alkanes, employing an intra-ruminal controlled-release device at the beginning of each trial. Hay intake per animal was measured from d 6 to 12 and sub samples were taken for chemical analysis. Rectal samples of feces were taken from each animal once/daily from d 8 to 14, freeze dried, and ground prior to alkane analysis. Alkanes were extracted from ground hay and feces. Feed intake was calculated from the dose rate of C-32 alkane and, the herbage and fecal concentrations of adjacent odd (C-33 or C-31) and even (C-32) chain length alkanes. Crude Protein, NDF, ADF, ash concentrations and In vitro dry matter digestibility (IVDMD) were 17.7, 42.2, 28.4, 7.9 and 71.7 for alfalfa, and 12.4, 56.5, 30.4, 6.9 and 69.1% for fescue/alfalfa mixture, respectively. For both diets, intake estimated from C-33:C-32 ratio was not different from the measured intake, but intake estimated from C-31:C-32 ratio was lower (p<0.05), than the measured intake for both diets. The average estimated forage intake from C-33:C-32 ratio was 4.86 and 0.69% below than the measured intake for alfalfa and, fescue/alfalfa mixed diets, respectively. The respective estimates with C-31:C-32 ratio were 9.59 and 11.33% below than the measured intake. According to these results, alkane C-33:C-32 ratio is better than alkane C-31:C-32 ratio for the estimation of intake by beef steers.
- Opportunities for detection and use of QTL influencing seasonal reproduction in sheep: a reviewNotter, David R.; Cockett, Noelle E. (2005-12-15)Genetic improvement in traits associated with seasonal breeding in sheep is challenging because these traits have low heritabilities, are generally not expressed until late in life, are commonly recorded only in females, and are expressed only in some lambing seasons and management systems. Detection of quantitative trait loci and their use in marker-assisted selection could therefore substantially enhance selection responses. A population of sheep with an extended breeding season was developed through selection for fertility in spring matings and provides opportunities for further study of candidate genes influencing seasonal breeding. In particular, the melatonin receptor 1a gene is polymorphic in many sheep breeds and appears to influence a number of seasonal reproductive responses. In addition, a variety of clock genes have been identified in laboratory mammals and shown to influence biological rhythms. Mutations in these clock genes have been identified and shown to influence circadian periodicities and reproductive patterns in golden hamster and mouse. In sheep, expression of clock genes in the suprachaismatic nucleus and pars tuberalis (PT) suggests that "calendar" cells in the ovine PT play a role in maintaining circannual rhythms. Thus the various clock genes represent potentially important candidate genes that may be involved in control of seasonal breeding.