Effects of estimated breeding values of sires on the performance of steer progeny in Hanwoo carcass traits

One of the main objectives of this study was to compare the differences of mean phenotypic values among steer progeny from 632 Korean proven bulls (KPN) with respect to their sire grade. Each sire was classified into one of the four grades (A, B, C, and D) on the quartiles of total index calculated by adding standardizing estimated breeding values (EBVs) for carcass weight (CWT), backfat thickness (BFT), eye muscle area (EMA), and marbling score (MAR), giving weights of 1: -1: 1: 1, respectively. The EBVs of sires were derived from the slaughter records of 289,606 Hanwoo cows and steers, while the comparison of progeny means by sire grade was conducted on the slaughter records of 369,580 steers. Comparisons were conducted via Tukey’s method following analysis of variance using a linear model that incorporated fixed effect of sire’s grade, contemporary group, and linear and quadratic effect of slaughter age. Significant differences of progeny means between sire grades were observed in most paired comparisons (p<0.05). The mean differences between progeny from the highest (Grade A) and lowest (Grade D) sire grades were 27.83kg for CWT, -1.16mm for BFT, 7.46cm² for EMA, and 0.91 for MAR. These results underscore the substantial impact of sire’s EBV on the progeny phenotype. Furthermore, providing genetic values of KPN, not only the EBVs but also the evaluated grades based on total index, is expected to enhance Hanwoo breeding programs of farms.