Estimation of genetic parameters for growth and carcass traits for Korean native cattle

Estimates of variance components and genetic parameters for weight traits such as birth (BW), weaning (WW), and six month weights (W6), postweaning traits such as yearling (YWT), eighteen month (WT18), and slaughter weights (SWT), and carcass traits such as marbling score (MS), dressing percentage (DP), and ribeye area (REA) were estimated for Korean Native Cattle which is called Hanwoo. Data from 1974 through 1995 were obtained from the National Livestock Research Institute in Rural Development Administration of Korea. Estimates of genetic parameters were obtained with REML using animal models. Estimates of direct and maternal heritabilities were .09 and .04 for BW, .03 and .05 for WW, .02, and .07 for W6, respectively. The direct-maternal genetic correlations for BW, WW, and W6 were positive. Estimates of direct genetic correlations between BW and WW, BW and W6, and WW and W6 were large: .52, .45, and .90, respectively. Genetic correlations (.69, .74, and .97) were moderately positive for maternal effects of BW with WW and W6, and extreme for WW with W6. Grandmaternal effects do not seem to be important for preweaning traits. Estimates of variance components were the same for models including or not including grandmaternal effects as the estimate of variance due to grandmaternal effects was zero for all traits. Estimates of direct heritability for YWT, WT18, and SWT were .14, .11, and .17, respectively. Estimates of maternal heritability for YWT was .04. The direct-maternal genetic correlation for YWT was strongly negative (−.81). Estimates of direct genetic correlations between YWT and WT18, YWT and SWT, and WT18 and SWT were large: 1.00, .87, and .97, respectively. Maternal effects seemed to be important for yearling weight and sire x region x year-season (SRYS) interaction effects may be important for postweaning traits. Estimates of heritability for MS, DP, and REA with covariates to adjust for backfat thickness (BT), slaughter day (SD), and slaughter weight (SW) were .07, .05, and .02 for MS, .06, .07, and .22 for DP, and .11, .11, and .21 for REA, respectively. Estimates of direct genetic correlations with BT as covariate between MS and DP, and DP and REA were −.95, and .30, respectively. Estimates of direct genetic correlations with SD as covariate between MS and DP, and MS and REA were −.93, and .31, respectively. Estimates of direct genetic correlations with SW as covariate between MS and REA, and DP and REA were .48, and .89, respectively. Choice of covariates (BT, SD, or SW) for the model seems to be important for carcass traits for Korean Native Cattle. Including maternal and SRYS interaction effects in the model for genetic analysis of dressing percentage and ribeye area may be important because SYRY interaction effects seem to be confounded with variance components