Variances Due to Direct and Maternal Effects on Weaning Weight in Indigenous Nguni Cattle of Zimbabwe

Abstract

Variance components for weaning weight (WWT) in indigenous Nguni cattle were estimated using Restricted Maximum Likelihood method. A single trait animal model was fitted, allowing for genetic maternal effects and a genetic covariance between direct and maternal effects. Estimates of heritability for direct genetic effects (h²_A), maternal genetic effects (h²_M) and the genetic covariance between direct and maternal effects as a proportion of the total variance (c_AM) for weaning weight were 0.25, 0.17, -0.18, respectively. Direct additive genetic variance was larger than maternal variance. The correlation between direct and maternal effects was negative implying that selection should be directed at both components considering the maternal heritability estimate, which was moderate.