Data on 23,251 Nelore calves weaned from 1994 to 1997, belonging to Agropecuária Jacarezinho Ltda., were analyzed to estimate the influence of environmental effects of age of dam, julian date of birth and age of calf at weaning on visual scores of conformation (C), precocity (P) and musculature (M). All effects significantly influenced the visual scores. The analyses showed that the calves with the best scores of C, P and M at weaning were those from dams with 7, 8 and 9 years of age. The best visual scores were from animals that were born earlier in the calving season. For age at weaning, as older was the animal better were its scores. The highest scores were those from animals weaned at 220 days of age and the smallest scores were from animals weaned at 140 days of age. Therefore, to increase the accuracy of genetic evaluations of young animals, adjusting factors for age of dam, julian date of birth and age at weaning, should be used, for conformation, precocity and musculature scores.
beef cattle; calf age; cow age; julian date of birth; visual score
