PSI-19 Bovine chromosome 19 VDR and GPRC5C genotypes are associated with udder conformation traits in crossbred beef cattle

Abstract

Abstract Udder characteristics are related to infection susceptibility and a calf’s ability to suckle its dam. Teat shape, teat size, udder suspension, and udder balance are main factors producers examine when evaluating cows, as per the Beef Improvement Federation guidelines. Based on previous studies that have identified genomic regions of interest for udder conformation, our objective was to determine if CAPN3, VDR, LETM1, GPRC5C, REN, and ABHD2 genes were associated with udder conformation. Crossbred heifers born in 2014 (n = 90) and 2015 (n = 73) at the Dickinson Research Extension Center were udder scored (1 to 9 scale, where higher score is more desirable) as heifers, placed in the breeding herd, then scored at each successive calving and weaning event until calving of 2018. Heifers were genotyped on the GeneSeek Genomic Profiler 150K, where SNP were selected for this study if located within these genes based on UMD3.1 coordinates (n = 24 SNP). Average scores per animal for each udder trait were modeled using general linear model procedures of SAS with fixed effects of primary breed (n = 9), year born (n = 2), frame score group (n = 4) and individual SNP. Least square means were adjusted using the Tukey-Kramer method. Significant associations between SNP and udder characteristic were: BovineHD0500009456 (VDR; P = 0.034; teat size), ARS-BFGL-NGS-27636 (GPRC5C; P = 0.042; teat shape), and BovineHD1900016305 (GPRC5C; P = 0.011; udder balance). Previous studies in other species have found VDR and GPRC5C (both on BTA 19) to be important for udder conformation. Particularly, ontology searches suggest VDR is involved with mammary tissue involution and branching and GPRC5C is involved with cell membrane integrity and regulation of retinoic acid. If these relationships hold true in cattle, then these markers may provide a viable option for selecting improved udder conformation.