Data of scrotal circumference and female reproductive traits were analyzed to estimate heritabilities and genetic correlations. Data were obtained from 11 farms by the same company, located in the States of São Paulo, Mato Grosso do Sul and Goiás. Variance components were estimated by restricted maximum likelihood using two-trait animal models. For traits with repeated measures, two mathematical models were used: including or not the permanent environment of the cow. Analyses that not included the permanent environment of the cow showed the following heritabilities 0.51, 0.12, 0.17, 0.06 and 0.13 for scrotal circumference (SC), age at first calving (AFC), days to calving (DC), calving interval (CI) and gestation length (GL), respectively. In these analyses, the genetic correlations were: -0.22 (SC x AFC), -0.04 (SC x DC), 0.10 (SC x CI) and --0.04 (SC x GL). When permanent environment of the cow were included in the model, heritabilities of DC (0.07) and GL (0.06) were smaller, indicating that models without permanent environment of the cow can overestimate the additive genetic variance of these two traits. However, the CI parameters did not change with the inclusion of permanent environment of the cow in the model. The scrotal circumference showed favorable genetic correlations with AFC, DC and GL, but the values in overall were low. These results allow utilizing SC as a selection criterion to improve the female fertility efficiency.
reproductive traits; genetic correlation; animal model; scrotal circumference
