Genetic Evaluation of Carcass Traits of Commercial Steers at Different Slaughter End–points

Carcass records, including pedigree, for 10,441 steers born from 2003 to 2008 and 21,711 animals total; were made available by the Pyengchang Youngwal Jungsun Livestock Cooperative. Data for each trait were adjusted for each of 5 end points: age (EPA), back fat (EPB), carcass weight (EPC), eye muscle area (EPE), and marbling score (EPM), and adjustments were made by fitting a linear. Genetic parameters were estimated using ASREML, which uses an average information algorithm. At different slaughter end points, heritability estimates for CWT (range=0.25 to 0.37) and EMA (range=0.17 to 0.33) were more significantly different than heritability estimates for BE (range=0.41 to 0.42) and MS (range=0.40 to 0.45). Genetic correlations between BF and CWT, EMA and CWT, and EMA and MS were positive, and those between BE and EMA and BF and MS were negative. The genetic correlation between CWT and MS yielded conflicting results. Correlations of sire breeding value for BF, CWT, EMA, and MS were in the range of 0.91 to 0.99, 0.75 to 0.93, 0.72 to 0.95, and 0.90 to 0.99, respectively, and those of the dam were in the range of 0.90 to 0.97, 0.73 to 0.94, 0.71 to 0.94, and 0.91 to 0.99, respectively. Further study will be needed to determine whether these alternative end points result in a more accurate estimate of BV than the traditional age end point.