Genome-wide Association using High Density Genotypes for Calving Difficulty in Dairy and Beef Cattle

Abstract Text: The objective of this study was to use high density genotypes (630,337) to identify genomic regions associated with both direct and maternal dystocia in three common cattle breeds (Holstein-Friesian, Charolais and Limousin). Previously reported QTL associated with dystocia in other BovineSNP50 genotyped populations were again identified, with one genomic region on chromosome 18 supporting very strong evidence of an underlying causative mutation and accounting for 3.1% of the genetic variation in direct calving difficulty. Several associations with maternal calving difficulty were also detected near previously identified QTL regions and also QTLs associated with birth-weight, bone-density and calf-size located on chromosomes 2, 3 and 4.  Novel associations were also reported for each trait. Genomic regions that were significant in all three breeds were also identified with regions on chromosomes 2 and 3 showing the strongest associations with direct and maternal calving difficulty respectively.

Keywords: genome-wide association study

calving difficulty

dystocia