For this study, after editing the data, 87,372Nelore cattle visual scores of conformation (C), precocity (P) and musculature(M) at weaning were utilized. The aim of this work were to study the effectsof age of dam at calving, Julian date of birth and age of calf at weaning onconformation, precocity and musculature visual scores and to estimate adjustmentfactors for these effects. The model included fixed effects of contemporarygroup (herd, paddock, year and month of birth, sex and management group at birthand at weaning), and the effects of age of dam at calving (for each sex), Juliandate of birth and age of calf at weaning as covariables. A quadratic quadraticsegmented polynomial was utilized for age of dam at calving. For Julian dateof birth a segmented polynomial with three quadratic segments was considered,whereas a quadratic ordinary polynomial was used for age of calf at weaning.Every effect included in the model significantly influenced the visual scores.Only including the month or season of birth in the contemporary group definitionwas not sufficient to adjust for differences in visual scores due to date ofbirth. For genetic evaluations of animals the visual scores at weaning mustbe adjusted for age of dam at calving, Julian date of birth and age of calfat weaning.
