Association of udder traits with single nucleotide polymorphisms in crossbred Bos indicus–Bos taurus cows1,2

Abstract

The size, support, and health of udders limit the productive life of beef cows, especially those with background, because, in general, such cows have a reputation for problems with udders. Genomic association studies of bovine udder traits have been conducted in dairy cattle and recently in Continental European beef breeds but not in cows with background. The objective of this study was to determine associations of SNP and udder support scores, teat length, and teat diameter in half (Nellore), half (Angus) cows. Udders of cows ( = 295) born from 2003 to 2007 were evaluated for udder support and teat length and diameter ( = 1,746 records) from 2005 through 2014. These included a subjective score representing udder support (values of 1 indicated poorly supported, pendulous udders and values of 9 indicated very well-supported udders) and lengths and diameters of individual teats in the 4 udder quarters as well as the average. Cows were in full-sibling or half-sibling families. Residuals for each trait were produced from repeated records models with cow age category nested within birth year of cows. Those residuals were averaged to become the dependent variables for genomewide association analyses. Regression analyses of those dependent variables included genotypic values as explanatory variables for 34,980 SNP from a commercially available array and included the genomic relationship matrix. Fifteen SNP loci on BTA 5 were associated (false discovery rate controlled at 0.05) with udder support score. One of those was also detected as associated with average teat diameter. Three of those 15 SNP were located within genes, including one each in (), (), and (). These are notable for their functional role in some aspect of mammary gland formation or health. Other candidate genes for these traits in the vicinity of the SNP loci include () and (). Because these were detected in Nellore-Angus crossbred cows, which typically have very well-formed udders with excellent support across their productive lives, similar efforts in other breeds should be completed, because that may facilitate further refinement of genomic regions responsible for variation in udder traits important in multiple breeds.

Genome-wide association study for mammary structure in Canadian Angus cows

“…These findings suggest that these are polygenic traits mainly influenced by distinct genes since there are many genomic regions with small additive effects on teat and udder structure, and that most of these are not commonly shared between the two traits. This is in line with previously reported genetic correlations between the traits ranging from 0.46 to 0.81 [7,8,27], as well as with other GWAS studies that found distinct genes associated with teat and udder score in beef [14] and dairy cattle [9].…”

“…Aoki et al [51] suggest that (in mice, at least) protein tyrosine phosphatases are upregulated both during this proliferation phase of mammary gland and the involution phase, and down regulated during lactation. Regarding udder structure in bovine, PTPRR has been identified as upregulated or significantly associated with udder health and structure [52]. Herring et al [14] found the PTPRR gene in close physical proximity with significant SNPs identified by GWAS for udder support and structure in Angus-Nellore crossbred cows.…”

“…In Fleckvieh cattle, Pausch et al [13] identified QTL significantly associated with multiple mammary phenotypes such as udder depth, central ligament score, and teat length and thickness identified. And, in Angus-Nellore cross cows, Tolleson et al [14] have performed GWAS for udder support score and teat size.…”

Determination of genetic variation within the <i>DYRK2</i> gene and its associations with milk traits in cattle

“…According to previous research, intron mutations may affect the host genes factors and interaction between tran- scription (Van et al, 2003;Fushan et al, 2009). Therefore, we used the online software Jaspar Genereg (http://jaspar.…”

Genome-wide associations for udder and teat conformational risk factors for mastitis in Holstein cows

“…While Pausch et al had extremely high density genetic data, they relied on bull genotypes and the indirect phenotyping of their daughters, raising external validity concerns. Currently, only one study has directly associated udder traits with cow genotypes, relating beef cow teat length, teat diameter, and a composite "udder support" score to genomic data from the low-density Bovine Illumina50k chip (13). Large-scale studies using genotype imputation from low density SNP arrays may maximize genome coverage and make large sample sizes more practical, but they introduce bias towards population averages and limit researcher ability to detect rare variants (14).…”