Genome-wide association for heifer reproduction and calf performance traits in beef cattle

The aim of this study was to identify SNP markers that associate with variation in beef heifer reproduction and performance of their calves. A genome-wide association study was performed by means of the Generalized Quasi-Likelihood Score (GQLS) method using heifer genotypes from the BovineSNP50 BeadChip and estimated breeding values for pre-breeding body weight (PBW), pregnancy rate (PR), calving difficulty (CD), age at first calving (AFC), calf birth weight (BWT), calf weaning weight (WWT) and calf pre-weaning average daily gain (ADG). Data consisted of 785 replacement heifers from three research herds namely; Brandon Research Centre, Brandon, University of Alberta Roy Berg Kinsella Ranch, Kinsella and Lacombe Research Centre, Lacombe, Canada. After applying a false discovery rate correction at a 5% significance level, a total of 4, 3, 3, 9, 6, 2, and 1 SNPs were significantly associated with PBW, PR, CD, AFC, BWT, WWT and ADG, respectively. These SNPs were located on chromosomes 1, 5 - 7, 9, 13 - 16, 19 - 21, 24, 25 and 27 - 29. Chromosomes 1, 5 and 24 had SNPs with pleiotropic effects. New significant SNPs that impact functional traits were detected, many of which have not been previously reported. The results of this study support quantitative genetic studies related to the inheritance of these traits, and provides new knowledge regarding beef cattle quantitative trait loci effects. The identification of these SNPs also provides a starting point to identify genes affecting heifer reproduction traits and performance of their calves (BWT, WWT and ADG), improve the understanding of the biology underlying these traits, and for potential use in marker- and genome-assisted selection and management.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author