Genetic analysis of some reproductive traits and their relationship with weight traits in Nellore cattle

Aiming to study age at first calving for males exposed to bulls for the first tone 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: IS month weight - PESSOB: and weight gain from weaning to 18 months - GP345) tit Nellore cattle, data sets varying from 6,030 to 94,637 observations were analyzed. Analyses were processed using for reproductive traits were: 0.18 (IPP14), 0.02 (IPP26), two-trait animal models. Heritability estimates 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, tit 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.