Multibreed genetic evaluation in bovines using simulated data employing a composite population

Abstract

Genetic evaluations in Brazil are performed within each animal breed; however, with the wide range of extant genetic groups in the country and the increased use of genetic crossing as a form of rapid meat production, more elaborate programs that can jointly evaluate animals of different genetic groups are needed. Genetic evaluation of a composite breed is difficult because of the variation in the genetic composition of a given herd, as well as the inclusion of non-additive genetic effects among breeds that can be important for selecting traits in certain breed combinations. Newer models include additive and non-additive effects; however, few studies have investigated these aspects in tropical breeds. The aim of this study was to simulate genetic values to compare different models. Non-inclusion of maternal effects in models leads to overestimation of variance and direct heritability. Estimates of the biological additive effects are influenced by the maternal effects; however, estimates of the non-additive effects are minimally influenced by the maternal effects and are well estimated in any situation. The studied models effectively predict the direct genetic values.

Genomic studies in Montana Tropical Composite cattle

“…The efficiency in the selection process of genetically superior animals in breeding programs, whether purebred, crossbreds or composite animals, depends on the accuracy of estimation of the genetic value of the animals at a young age. The methodological procedures used in the genomic evaluation for multi-breed animals allow more accurate predictions of genetic values through direct comparison between animals of different breed compositions and for the additive and non-additive genetic components BUENO et al 2011, BOCCHI et al, 2016DUENK et al, 2020;GRIGOLETTO et al, 2019;. However, as reported by Elzo and Borjas (2004), , and Misztal et al (2013), these statistical genetic models are complex, providing mismatch between genetic components and inclusion of non-additive genetic effects, dominance and epistasis.…”