Abstract #648

# 648
Genetic analysis of hair coat shedding in beef cattle with data collection using a practical strategy.
Trent Smith*1, Michael D. MacNeil2, Joseph P. Cassady3, 1Mississippi State University, Mississippi State, MS, 2Delta G, Miles City, MT, 3South Dakota State University, Brookings, SD.

Hair coat characteristics can affect adaptability of beef cattle and performance in various environments. Objectives of this study were to examine the usefulness of an annual hair coat shedding score (HCS) during the spring transition period and determine its relationship with maternal productivity as indicated by weaning weight (WW). Data were collected on 5,294 purebred Angus cows in May of 2011 and 2012 from various herds throughout the Southeastern US, Missouri, and Texas. Measurements included a HCS (1–5) and BCS (1–9) scored independently by 2 trained technicians and averaged. The WW of calves were obtained from the breed association database. The data included 2,225 cows that were observed in both years. Two bivariate analyses were conducted to examine the relationships of HCS with BCS and WW. The same model was used to analyze HCS and BCS. It included fixed effects of contemporary group and age, and random direct genetic and permanent environmental effects due to animals. The model for WW included fixed effects of contemporary group, age of dam and sex, and a linear covariate for age of calf at weaning. Random effects in the model for WW were direct and maternal genetic effects, and a permanent environmental effect due to dams. Phenotypic correlations of HCS with BCS and WW were 0.17 and approximately zero, respectively. Heritability estimates for HCS and BCS were 0.42 ± 0.03 and 0.12 ± 0.03, with a genetic correlation of −0.25 ± 0.10. For WW, heritability estimates were 0.28 ± 0.05 for direct and 0.05 ± 0.04 for maternal effects. The genetic correlation for WW direct and maternal was −0.34 ± 0.24. Estimated genetic correlations of HCS with direct and maternal genetic effects on WW were 0.17 ± 0.22 and −0.30 ± 0.25, respectively. Results of this study suggest that HCS assessed once a year during a transitional period could be used in selection decisions if profitable in certain environmental conditions. Associations of HCS with other traits of economic importance need to be explored further.

Key Words: genetic variances, hair shedding, beef cattle