Estimates of direct and maternal genetic effects on birth and weaning weights in Egyptian buffalo calves

Abstract

A total of 1173 first calves of Egyptian buffalo kept at Mehalet Mousa Farm, belonging to Animal Production Research, Ministry of Agriculture, Dokki, Cairo, Egypt during the period from 2000 to 2015 were used to estimate variances of direct and maternal genetic effects for birth weight (BW) and weaning weight (WW). Two animal models are used. Model 1 (full model) includes month and year of birth and sex as fixed effects and direct genetic, maternal genetic, covariance between direct and maternal genetic and residual as random effects. Model 2 is similar to model 1 while additive maternal genetic and covariance between direct and maternal effects were omitted from the analysis. Year of birth and sex had highly significant effects on BW and WW, while month of birth had no significant effects on both traits studied. Bulls of the buffalo had highly significant effects on BW and WW. Direct heritability estimates for BW are 0.30 and 0.33, for Model 1 and Model 2, respectively. Direct heritability estimates for WW are 0.34 and 0.39 for Model 1 and Model 2, respectively. Maternal heritability estimates are 0.10 and 0.03 for BW and WW, respectively. Phenotypic and genetic correlations among BW and WW are positive and highly significant. These results indicate the important of maternal genetic effect on birth weight.