Análise genética da habilidade de permanência em fêmeas da raça Nelore

The purpose of this study was to analyse of the stayability trait (STAY) of Nelore cows. Stayability was defined as the probability of calving at a specific age, or after that age, given that the cow calved at least one time prior to that age. The study was focused specifically on six year old groups, and the information corresponding to 55,682 animals were analyzed. Data were analyzed based on an a posteriori maximum threshold model to predict the genetic values, while the Gibbs sample was used to estimate the variance components. The analyses provided heritability estimate and standard deviation of 0.21 +/- 0.003 and average genetic tendency a year was of 0.14% for STAY. The estimates indicate that the use of this trait as a criterion for selection may contribute toward increased female fertility.