Master of Science (MS)


Animal Science (Animal, Dairy, and Poultry Sciences)

Document Type



The objective of this study was to test the association of single nucleotide polymorphisms (SNPs) with fertility in two populations consisting of Holstein cows and multi-generational Angus cows. The candidate gene approach was utilized and previously described SNPs were tested for possible associations with fertility. Single nucleotide polymorphisms on three genes were evaluated including leptin receptor LEPR, calpastatin CAST, and DGAT1. Fertility traits were evaluated in conjunction with production traits for Holstein females and growth traits for Angus females. One SNP was significantly associated with birth weight (P < 0.05) in Angus females while a trend (P < 0.10) was observed for two markers influencing birth weight performance and three markers influencing weaning weight performance. An association of two SNP for birth weight and back fat thickness in Angus females was identified.!A trend (P < 0.10) was observed for one marker within LEPR influencing average services to conception, two markers within CAST influencing average days open, two markers within CAST and one marker within DGAT1 influencing average protein production, and one marker within CAST and one marker within DGAT1 influencing average milk production. One SNP within LEPR was significantly associated with average milk production (P < 0.05) in Holstein females. An association of one SNP within CAST and one SNP within DGAT1 for average protein production and average milk production in Holstein females was identified. An association of one SNP within CAST for average days open and average protein production in Holstein females was also identified. The association of these markers indicates that the evaluated quantitative trait loci (QTL) region may harbor causative mutations responsible for the variation observed in fertility and production traits. Further evaluation of SNP in these regions is necessary in order to identify mutations accounting for the largest degree of variation for fertility and production traits.



Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Garcia, Matthew