Using a univariate and a multitrait analyses, the traits weight gain from birth to weaning (WGBW) and weight gain from weaning to yearling (WGWY) were analyzed on 4883 Charolais beef cattle, sons of 328 sires, to compare different models with the most complete model, although with more difficult applicability. The models were the MA1, animal model which included the direct effect of the animal and the genetic maternal effect; MA2, animal model which included the direct effect of the animal and the permanent environmental effect; MA3, which included the three effect (considered "the best"); MA4, animal model which included only the animal direct effect; MTV, the sire-dam model which included the direct genetic effect of the sire, plus the maternal genetic effect and the permanent environmental effect; MT1, sire model which included the genetic effect of the sire and the permanent environmental effect and the MT2, sire model which included only the direct genetic effect of the sire. The results showed that there were statistical differences among the models MA4 and MT2, comparing with the MA3 but only for WGBW. It was concluded that for WGBW the inclusion in the model of at least one effect (genetic maternal or environmental) was indicated, while for WGWY simple models, as the MA4 or MT2, could be utilized in substitution to the most complex models (MA3). The multitrait analyses were indicated, mainly because it presented the genetic correlation among the traits
permanent environmental effect; maternal effect; weight gain
