Integrating genomic evaluations for carcass and reproductive traits of composite cattle

Abstract

Livestock production is one of the main important components of the Brazilian economy. The country is recognized among the top worldwide beef producers and exporters. For this reason, the development and use of composite animals, such as Montana Tropical Composite, through the combination of different biological types represents a promising alternative to maximize production due to the exploration of heterosis retention and complementarity between the beef cattle subspecies Bos taurus taurus and Bos taurus indicus. Several methodologies have been applied in order to implement genomic evaluation, mainly for the population of multi-breed and composite animals. Therefore, the determination of the genetic correlation between the different traits of economic interest allows a better understanding of the magnitude and direction of correlated response in one trait, when selecting for another. The genetic correlation shows the extent of the expression between the same genes of different traits. The carcass traits have great slaughterhouse importance, being the target of the industry's bonus protocols. Reproductive traits, on the other hand, can be considered the most important in farms, such as fertility, precocity, reproductive longevity and the production of cows, which have an immediate impact on the quality and quantity of animals produced and commercialized annually. Therefore, estimating the genetic correlations between carcass and reproduction traits is essential to verify the possibility of appropriate selection to the bonus protocols for quality meat, without generating deficits in the reproductive indexes of the farms. This applies to the selection objectives of the Montana Tropical Composite breeding program, which aims at quality meat and high reproductive rates. Verifying the magnitude and direction of genetic correlations, as well as their changes due to the inclusion of genomic information, in this population is important for the selection program and national livestock. (AU)