Genetic relationship among stayability, scrotal circumference and post-weaning weight in Nelore cattle

Abstract

Improvement of female fertility has become of fundamental importance for profit maximization in the beef cattle herds. Consequently, animal breeding programs in Brazil have applied selection effort to traits related to reproduction as for scrotal circumference (SC), which is already incorporated to the selection routine of the breeders. However, studies have reported no favorable genetic correlation ( r g) of SC with some fertility traits. Recently, stayability (STAY) has been used as means to better indicate and improve female fertility. Values for r g of STAY with reproductive and productive traits are not available in literature. Therefore, the objectives of the present study are to analyze the r g between SC and STAY and STAY with weight at 550 days (W550) in Nelore cattle. Data set of 55,682, 28,507 and 59,750 animals for STAY, SC and W550, respectively, were analyzed using two-trait animal model based on Gibbs sampling algorithm. The estimate of posterior r g between STAY and SC was 0.07 ± 0.03, which can be considered as low and suggesting that STAY does not have sensible relation with SC. The r g of STAY and W550 was 0.15 ± 0.01, considered low, although positive. It means that selection for W550 should not negatively affect STAY.