Abstract
Infertility is one of the most economically important traits for the dairy cattle industry, accounting for 22.1 % of culled cows in 2017. Therefore, the objectives of this study were to identify genomic regions via genome-wide association studies (GWAS) and to retrieve the biological pathways that are associated with variation in fertility traits in the dairy cow. Fertility records including days open (DO), Times Bred to Conception (TBRD), Calving Ease (CE), and Days in Milk (DIM) from the Cal Poly Dairy were collected from the DairyComp management system. After quality control, 345 individuals and about 782,000 SNPs were used in the GWAS analyses. Significant SNPs were mapped to the corresponding genes that were used for in-silico functional analyses using DAVID Software. A total of 3, 3, 8, 3, and 7 SNPs were significantly associated with chloride transmembrane transport, neutrophil chemotaxis, cell adhesion, starvation response and nervous system development. The functional analyses suggested potential molecular mechanisms such as chloride transmembrane transport (P = 0.017) and neutrophil chemotaxis (P = 0.02) as significant enriched biological pathways involved with variations seen for DO. Cell adhesion was found as a significant (P = 0.004) biological pathway for TBRD whereas the analysis revealed the starvation response mechanism as significant (P = 0.005) for CE. Nervous system development was significantly (P = 0.0003) associated with DIM. These results from the current study will be validated in a larger population with higher density panel and sequence data.