Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/7/2017
Publication Date: 5/1/2017
Citation: Ortega, M., Denicol, A.C., Cole, J.B., Null, D.J., Taylor, J.F., Schnabel, R.D., Hansen, P.J. 2017. Association of single nucleotide polymorphisms in candidate genes previously related to genetic variation in fertility with phenotypic measurements of reproductive function in Holstein cows. Journal of Dairy Science. 100(5):3725-3734.

Interpretive Summary: A total of 26 single nucleotide polymorphisms were identified that were related to phenotypic estimates of fertility that had been previously associated with genetic merit for fertility in Holstein cows.

Technical Abstract: The objectives of this study were to evaluate the effect of 68 SNP previously associated with genetic merit for fertility and production on phenotype for reproductive and productive traits in a population of Holstein cows. In addition, we determined which SNP had repeated effects across three studies and two populations of Holsteins. Lastly, we determined the presence of these SNP in 12 other breeds of cattle. Holstein cows grouped based on predicted transmitting ability for daughter pregnancy rate (DPR): = -1 (n=1220) and = 1.5 (n=1053), and located on 11 farms in Florida and California were used. Data for up to five lactations for days open, services per conception, pregnancy rate at first service, milk yield, fat yield, and protein yield were evaluated. The effect of each SNP was analyzed using analysis of variance; the model included the random polygenic effect, genotype, lactation number and farm as main effects. A total of 26 SNP presented significant associations with fertility traits, and 32 SNP were associated with productive traits (P<0.05). A total of 46 SNP has association at least one trait in two separate studies, nine SNP had additive effects in the same direction for fertility and milk yield, 28 SNP associated with fertility were not associated with milk yield, and 15 SNP associated with fertility had no association with MY, FY and PY together. A range of 41-66 SNP were present in 12 other breeds of cattle, for more than half of the SNP the same minor allele in the Holstein population was the minor allele in each breed evaluated. The SNP associated with genetic and phenotypic estimates of fertility are likely to be informative markers for genetic selection in Holsteins and potentially in other breeds of cattle, there maintained their associations with fertility in different populations of Holsteins; and, for the majority of the cases had no association with productive traits making them of interest in selection schemes to improve fertility without negatively impact production in dairy cattle. The study of the role of these genes could provide new insights into the physiological regulation of fertility.