Estimation of Direct Additive Genetic and Maternal Variance for Growth Traits in Vrindavani Cattle

The growth records of Vrindavani calves were analyzed to estimate the variance components and genetic parameters using two univariate and a multivariate animal model based on algorithm of derivative free restricted maximum likelihood. These univariate animal models were simple animal model (AM I) and animal model with additional random maternal effect (AM II). The multivariate animal model (AM III) included all the traits under investigation by considering their relationship. For all growth traits (Birth weight and body weight at 3, 6 and 9 month) the estimate of additive genetic variance was highest in the simple animal model (AM I). The direct estimates of heritabilities were also inflated towards higher side for all the four traits using AM I. The multivariate animal models revealed lowest magnitude of direct additive genetic variances and thus direct estimate of heritabilities for all the traits. The direct estimates of maternal heritability ranged from 0.064 (Birth weight) to 0.197 (body weight at 6 month) and it was zero in 6 and 12 month body weights. The genetic correlations of birth weight with 3, 6 and 12 month body weights were low and non-significant because of significant impact of maternal effect on birth weight. However, the phenotypic correlations between traits were found to be positive and significant.