Genetic Parameters for Weaning Weight, Weaning Hip Height and Weaning Body Length of Crossbred Beef Cattle in Thailand

Abstract

Genetic parameters for weaning weight (WWT), weaning hip height (WHH) and weaning body length (WBL) of crossbred beef cattle among the Thai Native, Brahman and Charolais breeds raised in central Thailand were estimated using a derivative-free, restricted maximum likelihood algorithm. Multivariate animal models were employed to estimate the direct heritability (h2) of WWT, WHH and WBL and to estimate the maternal heritability (m2), the direct-maternal genetic correlation (ram), and the fraction of variance due to maternal permanent environmental effect (c2) only for WWT. The model fi tted contemporary group (CG) and sex as fi xed effects and weaning age and breed fractions of Brahman and Charolais as fi xed covariates. Estimates of h2 ranged from 0.54 to 0.68, 0.68 to 0.93 and 0.33 to 0.48 for WWT, WHH and WBL, respectively. The estimates of m2, ram and c2 for WWT ranged from 0.20 to 0.23, -0.38 to -0.36 and 0.00 to 0.08, respectively. The direct genetic correlations between traits ranged from 0.59 to 0.98. The high genetic correlations between traits indicated the possibility of performing selection for WWT based on the information from WHH and WBL. A simple direct genetic effect model was determined to be appropriate for analyzing the current data set based on the likelihood ratio test but the estimates of h2 for traits might bias upward.