Arkansas Animal Science Department Report 2002

The faculty and staff of the Animal Science Program are pleased to present the sixth edition of the Arkansas Animal Science Report. As with virtually all programs in the country, budget constraints presented serious challenges to teaching, research, and extension programming. However, the faculty and staff responded with innovation, good management, and hard work to maintain a productive program designed to benefit the students of the University and the citizens of the state. We are committed to remaining faithful to our Land-Grant mission. A sincere thank you is owed to Dr. Zelpha Johnson and Dr. Wayne Kellogg for editing this publication. We are proud that Meat and Poultry magazine ranked the animal and poultry programs at the University of Arkansas among the top four in the United States for 2003. This is a tribute to the dedicated and talented faculty in the Departments of Animal Science, Poultry Science, and Food Science and to their high level of cooperation

Estimates of Genetic and Phenotypic Trends of Growth Traits in Bali Cattle

The aim of this study was to estimate genetic and phenotypic trends for growth traits including birth (BW), weaning (WW) and yearling weight (YW) in Bali cattle. The number of cattle used to determine growth traits of BW, WW, and YW were 235, 215, and 178 heads, respectively. Estimation of breeding value, phenotypic and genetic correlation were calculated by Restricted Maximum Likelihood and General Linier Model (GLM) procedures, respectively. Genetic trends analysis was performed using the regression mean breeding values on birth year. Phenotypic and genetic correlation among BW and WW were 0.10 and 0.08 respectively and 0.90 and 0.70 for WW and YW respectively. The phenotypic trends for traits of birth and weaning weight were constant, whereas yearling weight was fluctuating from 2000 to 2008. Likewise, in the case of genetic trends, the birth and weaning weight were constant from 2000 to 2008 except for WW in 2005, whereas the genetic trends for yearling weight showed a fluctuation of wide range. According to the breeding value estimated for all traits, the best was the sire No. 0565, whose breeding value for BW, WW and YW were +0.07, +2.79, and +10.25 kg, respectively higher than the mean value of the population. The genetic trends showed that there have been a significant and positive genetic improvement in all growth traits and indicate that selection would be effective. Genetic correlation between WW and YW was high (0.70) which indicates that the selection on weaning weight might also increase yearling weight in Bali cattle

Estimating the Returns from Past Investment into Beef Cattle Genetic Technologies in Australia

Research and Development/Tech Change/Emerging Technologies,

Genetic Components of (Co)variance for Postweaning Growth, Carcass Composition and Meat Quality Traits Among Brahman-Influenced Beef Steers.

A genetic analysis was conducted on preweaning and postweaning growth and carcass composition records from steers produced in two long-term crossbreeding studies. In phase I, Angus (A), Brahman (B), Brangus (BR), Charolais (C) and Hereford (H) sires produced straightbred, F\sb1, back-cross, three-breed cross and 2- and 3-breed rotational crossbred steers (N = 708) from 1960 to 1968. Straightbred, F\sb1, back-cross, three-breed cross and 2-, 3- and 4-breed rotational crossbred steers (N = 1530) were produced from 1970 to 1988 by A, B, C and H sires in phase II. Direct and maternal additive and non-additive genetic effect contrasts were obtained. Heritabilities and genetic and phenotypic correlations were estimated for phase I using a multivariate mixed sire model and for phase II using an animal model. Direct additive genetic effects of B were smaller than the other direct additive genetic effects for hot carcass weight, total lean yield, marbling score and tenderness but not different than the average non-Brahman additive genetic effect for carcass weight adjusted ribeye area. Maternal additive genetic effects were smaller than direct additive genetic effects for carcass traits. Direct heterosis effects involving B were positive and larger than heterosis effects not involving B. Maternal heterosis effects were near zero for carcass traits. The ranking of genetic effects in phases I and II were similar. Heritability estimates for postweaning growth and carcass traits were moderate to large, except in the case of daily gain on ryegrass, which had a low heritability. Genetic correlations indicated a high association among weights, rates of gain and total lean yield. Increased growth and carcass weight had negative phenotypic and genetic correlations with carcass weight adjusted ribeye area. Genetic correlations among fat and meat quality traits were small, although the association between marbling score and Warner-Bratzler shear force tended to be favorable. Preweaning growth traits had positive correlations with carcass traits related to weight and total lean yield. Increasing percentage B was a significant source of heterogeneity among estimates of genetic and phenotypic (co)variances for ribeye area and Warner-Bratzler shear force

Relationships Among Beef Cow Productivity Traits and Single Nucleotide Polymorphisms in the Bovine Heat Shock Protein 70 Gene

When eukaryotes are exposed to stressors such as heat, toxins, and low oxygen levels, heat shock proteins (HSPs) are synthesized to maintain normal cellular function within the body. Single nucleotide polymorphisms in the heat shock protein 70 (Hsp70) gene have been associated with calving percentage, and Julian calving date in spring-calving crossbred Brahman cows (Rosenkrans, et al., 2010). Our objective was to determine associations between previously identified polymorphisms in the promoter region and coding sequence of the bovine Hsp70 gene and beef cow efficiency. We evaluated productivity traits, including Julian calving date and calving rates, of fall-calving cows at each single nucleotide polymorphism (SNP) site. Genomic DNA was extracted from blood samples collected from crossbred cows (n=109) and amplified by polymerase chain reaction (PCR) using specific forward and reverse primers. Upon amplification, samples were purified, quantified, and sequenced in a commercial laboratory. Sequences were analyzed to determine SNP and genotypes were assigned to each of them. Production data of the cows from 2012-2014 were analyzed at each SNP site. Cows with CD genotype at C895D calved about one week later (P = 0.0001) and tended (P \u3c 0.06) to have calves with lighter birth weights compared to cows with CC genotype. Genotype at G2033C affected (P \u3c 0.02) weaning weight and cow efficiency. Genotype of a haplotype composite (No SNP, Deletion, and Yes SNP) affected (P \u3c 0.02) Julian date and cow efficiency. Polymorphisms associated with the bovine Hsp70 gene were related to important cattle productivity characteristics. Selecting replacement cattle with known Hsp70 genotypes may result in herds that are more thermotolerant and sustainable