Heritability for stayability in Canchim beef cattle breed

The objective of this work was to evaluate the effectiveness of using the stayability of beef cows as selection criterion for the Canchim breed. Stayability was defined as the probability of a beef cow having three or more parities up to 76 months of age, given that she have calved at least once and was older than 76 months. Binary coding, with 0 indicating failure and I indicating success, was defined for each cow. An alternative coding, with four categories, used the values 0, 1, 2 and 3, respectively, for cows with less than three, three, four or five parities up to 76 months of age. The analises were perfomed with a single-trait sire and maternal grandsire model. Gibbs sampling was used to estimate variance components and heritabilities. The estimated heritability was 0.07 for the binary trait and 0.08 for the trait with the four categories. The results indicate small diferences in the estimated heritability for the binary and four-category models. They also suggest that the stayability in Canchim breed presents low potential for response to selection.