Genome-Wide Association Studies for Body Conformation Traits in Korean Holstein Population

SIMPLE SUMMARY: Holstein has been the most widely used dairy cattle breed in the Korean Peninsula since its introduction in 1885. Since the formal dairy herd improvement program was initiated in 1979, Holsteins have been extensively selected for Korean environments. While body conformation traits in dairy cattle are not typically considered direct economic traits for animal breeders, they are associated with various production traits, including health status, milking ability, and overall cow longevity. Consequently, these traits are recognized as significant factors in dairy cattle breeding programs worldwide. The dairy industry relies on consistent milk and calf production from cows, which presents challenges in today’s context. Conducting a genome-wide association study (GWAS) for body conformation traits in Korean Holstein cattle, using a large population, may enhance the power of detecting and mapping novel genes associated with these traits. To the best of our knowledge, this study represents the first-ever attempt to conduct a GWAS for body conformation traits in the Korean Holstein population. ABSTRACT: The objective of this study was to identify quantitative trait loci (QTL) and nearby candidate genes that influence body conformation traits. Phenotypic data for 24 body conformation traits were collected from a population of 2329 Korean Holstein cattle, and all animals were genotyped using the 50 K Illumina bovine SNP chip. A total of 24 genome-wide significant SNPs associated with 24 body conformation traits were identified by genome-wide association analysis. The selection of the most promising candidate genes was based on gene ontology (GO) terms and the previously identified functions that influence various body conformation traits as determined in our study. These genes include KCNA1, RYBP, PTH1R, TMIE, and GNAI3 for body traits; ANGPT1 for rump traits; MALRD1, INHBA, and HOXA13 for feet and leg traits; and CDK1, RHOBTB1, and SLC17A1 for udder traits, respectively. These findings contribute to our understanding of the genetic basis of body conformation traits in this population and pave the way for future breeding strategies aimed at enhancing desirable traits in dairy cattle.