Genomic selection for feed efficiency traits in Nellore beef cattle

Abstract

Animal feeding is the most important economic item of beef production systems. However, selection for feed efficiency has not been very effective due mainly to the high costs of obtaining phenotypes. Therefore, the selection based on genome SNP markers can be quite promising, taking into account the cost of genotyping the animals has reduced. Although there is no consensus among researchers related to the most appropriate methods for obtaining genomic values, several methods have been proposed. This project will be developed in order to compare two methods of genomic evaluation and determine the most suitable for the traits that will be studied, using high-density chips (Illumina High-Density Bovine BeadChip, 700 kb). Approximately 500 genotyped animals will be used to analyze the following traits: residual feed intake, dry matter intake and average daily gain. The genomic breeding values of the animals will be predicted by two procedures: single-step - by the inclusion of the relationship matrix of genotyped animals corrected by the relationship matrix of the ungenotyped animals; multiple steps - which consists of 3 stages: a) genetic evaluation using traditional animal model, b) prediction of genomic effects for genotyped animals, and c) prediction of genomic values obtained by an index formed using means of the expected progeny differences of parents, generated by the traditional genetic evaluation and solutions obtained in the second step. (AU)