Identification of quantitative trait loci and associated candidate genes for pregnancy success in Angus – Brahman crossbred heifers

Development of genomic tools to identify females with high genetic merit for reproductive function could increase the profitability and sustainability of beef production. Here, genome-wide association studies (GWAS) were performed on pregnancy outcome traits from a population of Angus – Brahman crossbred heifers. Furthermore, a validation GWAS was performed using data from another location. Heifers were genotyped with the Bovine GGP F250 array that contains ~250,000 SNPs. In the discovery population, heifers were bred in winter breeding seasons involving a single round of timed artificial insemination (AI) followed by natural mating for three months. Three phenotypes were analyzed: pregnancy outcome to first-service AI (PAI; n = 1481), pregnancy status at the end of the breeding season (PEBS; n = 1725), and pregnancy score (Pregscore where 1 = pregnant to first-service AI, 2 = pregnant to bull, 3 = not pregnant; n =1481). The heritability for PAI was estimated as 0.149. One large quanti...