Estimation of Heritabilities for Growth and Carcass Traits and Their Genetic and Phenotypic Correlations in Japanese Black Cattle

Abstract

Using the records of the progeny testing of Japanese Black cattle in 15 different testing stations, heritabilities and genetic and phenotypic correlation coefficients for growth and carcass traits were estimated. The progeny testing records were of 1, 684 steers sired by 208 bulls. Mathematical analyses were done using HARVEY'S least squares analysis program, LSML76 (1977), and the source of variations were year-station, sire within year-station and partial regression on initial age of progeny. The results are summarized as follows: 1. There were statistically significant differences in year-station and sire within year-station for all the growth and carcass traits except final grade (p<.01). 2. The effects of initial age on daily gain (DG), final body weight, marbling score, and carcass grade were linearly significant. On the other hand, the same effects on final withers height and carcass weight were quadratically significant (p<.05). 3. The heritability estimates were 0.59 for DG, 1.22 for dressing percentage, 0.53 for final body weight, 0.76 for final withers height, 0.50 for final grade, 0.61 for carcass weight, 1.15 for back fat thickness, 0.40 for marbling score, 0.94 for rib eye area, and 0.37 for carcass grade. 4. There were relatively high genetic correlations between DG and final body weight (0.85) and between DG and carcass weight (0.78), low genetic correlations between DG and marbling score (0.05) and between DG and carcass grade (0.15), and moderate genetic and phenotypic correlations between DG and rib eye area (0.35 and 0.30, respectively). The genetic and phenotypic correlations between marbling score and carcass grade were extremely high (0.97 and 0.77, respectively).