Genetic Analysis of Growth in Performance Tested Young Bulls accounting for Indirect Genetic Effects

Abstract Text: The growth trajectories of young bulls of  Italian native dual purpose breed Rendena were studied to evaluate the associative components (indirect genetic effects, IGEs) provided by group mates in performance test stations. Periodical weightings of 1282 individuals in 96 groups were analyzed via random regression model (RRM) and compared with multiple-traits estimations (MTM), using both classical and “competitive” (i.e., with associative components) models. Heritability from classical models ranged between 0.213 and 0.360, whereas direct and associative heritabilities were 0.228 and 0.135 in RRM, and assumed the same value of 0.155 in MTM. Only the direct-additive genetic correlation was opposite in verse under the two approaches, suggesting further work on the topic. The present study has shown the possibility to analyse associative components using a random regression analysis.

Keywords:

Indirect genetic effects

Random regression model

Growth