This study aimed to evaluate the performance of Nellore and their crosses with Blonde d'Aquitaine (½Nellore + ½ Blonde d'Aquitaine) cattle from birth to weaning kept in grazing system in the State of Alagoas. 1,279 measures of birth weight (BW) and weaning weight adjusted to 210 days (P210) were analyzed for the period between 2005 and 2010. We used SAS® adopting a significance level of 5%. The average for BW and P210 were 31.60 kg and 158.66 kg respectively, for animals Nellore cattle, and 33.05 kg and 167.03 kg, for crossed animals. There was no interaction (P<0.05) between genetic group and sex, for any variable analyzed. We observed significant effects of genetic group, sex and season of birth (P<0.05) on birth weight. The genetic group and sex were significant on the P210. The effect of calving season was significant on birth weight, but no effect on P210 was observed, probably due to climatic variation found in the region. Males had higher body weights (P<0.05) showing sexual dimorphism. The Nellore cattle are superior to crossbred animals in all characteristics considered, providing even heavier calves at birth, without, however, presenting dystocic deliveries. The crossbred animals are also suitable in relation to large breed adaptation to climatic conditions and management which were submitted, making it an excellent option for crosses in the Northeast, in climatic conditions similar to this study.
breeding; calves; growth rate; P210