Three different models including or not the direct and maternal non-additive effects and the fixed effects of contemporary group, parity order, direct and maternal heterosis and the direct and maternal additive genetic random effects were compared for predicting breeding values for pre-weaning daily gain in a composite cattle population in tropical climate. The analyses were done in two stages: firstly, breed and individual and maternal heterosis effects were estimated and after variances and the heritability were obtained for prediction of breeding values of the animals. The breed additive effect seemed to be overestimated when the maternal effect was not included in the model. Estimates of additive and maternal breed effects and individual and maternal heterosis for pre-weaning daily gain were significantly different for the biological types. Direct and maternal heritability estimates from analyses using data adjusted for direct and maternal non-additive effects were respectively 0.22 and 0.20. The maternal breed effect and individual and maternal heterosis should be included in models used for genetic evaluation of pre-weaning daily gain in this composite cattle population.
biological types; heritability; heterosis; maternal effect