Genetic analyses of stayability to consecutive calvings in taurine breeds

Summary The trait stayability is a way of assessing productive life and has been measured late in the cow's life. Measuring the stayability to each calving is a strategy that can be implemented to obtain earlier indicators of longevity. Thus, the objective with this study was the estimation of genetic parameters for stayability to consecutive calvings for Angus and Hereford cattle breeds. By using random regression animal models, different orders of Legendre orthogonal polynomials were compared. According to DIC, the model with cubic Legendre polynomials (4 coefficients) was the most appropriate. Heritability estimates ranged from 0.03 to 0.07 and 0.05 to 0.08 for Angus and Hereford, respectively, with estimates for Angus slightly higher than that for Hereford. Heritability estimates had a similar trend for both breeds, being higher for stayability at intermediate calvings (fourth to sixth). Genetic correlation estimates were from 0.47 to 0.87 and 0.63 to 0.93 for Angus and Hereford, respectively, and were higher for stayability between closer calvings. The estimates observed for genetic correlations indicate that the genetic control of stayability to each calving is performed by the same group of genes, at least partially. For this reason, the selection to increase the probability of stayability to second calving can result in a moderate genetic gain in subsequent calvings. Cubic random regression models can be used for the genetic evaluation of the stayability to consecutive calvings in beef cattle.