Aiming to study age at first calving for females exposed to bulls for the first time around 14 months of age (IPP14) or around 26 months of age (IPP26), days to calving (DPP), gestation length (DG) and scrotal circumference (PE) and their relationships with weight traits (birth weight - PESNAS; weaning weight - PESDES; 18 month weight - PESSOB; and weight gain from weaning to 18 months - GP345) in Nellore cattle, data sets varying from 6,030 to 94,637 observations were analyzed. Analyses were processed using two-trait animal models. Heritability estimates for reproductive traits were: 0.18 (IPP14), 0.02 (IPP26), 0.06 (DPP), 0.26 (DG), and 0.46 (PE). Correlations between PE and weight traits indicated that weights were not antagonic to PE. Although genetic correlations between PESDES and reproductive traits of females were low to moderate, in unfavorable direction, it would not be recommended to increase adult size of the animals in those herds to avoid the risk of low reproductive performance. The traits PESSOB and GP345 were not antagonic to sexual precocity and fertility of females, except gestation length.
Bovine; genetic correlation; heritability; age at calving; body weight; scrotal circumference
