The aim of this study was to estimate the heritability of stayability (HP) in Caracu cattle in order to evaluate its usage as a selection criterion for longevity. Stayability was defined as the probability of a cow to be producing in the herd at the ages of 48 (HP48), 60 (HP60) and 72 (HP72) months. Binary observations indicating failure (zero) or success (one) were assigned to records on 5487, 4947 and 4308 cows with at least two lactations at the ages of 48, 60 and 72 months, respectively. Variance components and heritability for HP48, HP60 and HP72 were estimated using a sire model including the fixed effects of contemporary group, classes of milk yield at first calving, classes of age at first calving and the interaction between milk yield and age at first calving classes by Gibbs sampling with the MTGSAM for threshold program. Average heritability estimates for HP48, HP60 and HP72 were 0.28 ± 0.07, 0.27 ± 0.07 and 0.23 ± 0.07 respectively. These results indicate that HP can be used as selection criterion for longevity in Caracu cattle.
dual purpose cattle; longevity; threshold trait
