Thesis
Multi-breed identification of loci associated with fertility traits in heifers and cows
Washington State University
Master of Science (MS), Washington State University
12/2019
DOI:
https://doi.org/10.7273/000004182
Handle:
https://hdl.handle.net/2376/125384
Abstract
To improve the ability of cattle to conceive and maintain a full-term pregnancy, two studies were undertaken. The objectives of the first study were to identify loci and gene-sets in crossbred beef heifers associated with conception at the first service (HCR1) or multiple services (TBRD). Heifers (n = 709) from a commercial beef operation underwent one round of artificial insemination, before exposure to bulls for natural service for 50 days. Pregnancy and time of conception were determined by ultrasound 35 days after the conclusion of the breeding season so that 300 heifers could be selected for genotyping with 43,984 single nucleotide polymorphisms (SNPs). A genome-wide association analysis (GWAA) identified one locus as associated (P = 8.97 × 10-6) with TBRD on BTA19. A gene-set enrichment analysis using single nucleotide polymorphisms (GSEA-SNP) identified one gene-set as enriched (NES = 3.15) with TBRD. The objectives of the second study were to identify loci, positional candidate genes, gene-sets, and pathways associated with spontaneous abortion (SA) in Holstein heifers and primiparous cows and compare these results with previous human SA studies to determine the suitability of cattle as a human SA model. Cattle were selected for genotyping after pregnancy was determined at gestation day 35 and calving dates were recorded. A GWAA, GSEA-SNP and an Ingenuity Pathway Analysis compared 43,984 genotypes of 499 heifers and 498 cows that calved at full-term to 62 heifers and 28 cows experiencing SA. Twenty-three loci and 21 positional candidate genes were associated (P < 1 × 10-5) with SA and eight gene-sets (NES > 3.0) were enriched for SA. Of the genes and gene sets associated with fertility in cattle, one positional candidate gene and two gene-set had also previously been associated with human SA. These studies identified loci, genes, and gene-sets associated with fertility and provide support for using cattle as a potential model for fertility traits such as SA in humans.
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Details
- Title
- Multi-breed identification of loci associated with fertility traits in heifers and cows
- Creators
- Kayleen Farron Oliver
- Contributors
- Holly Louise Neibergs (Advisor) - Washington State University, Animal Sciences, Department of
- Awarding Institution
- Washington State University
- Academic Unit
- Animal Sciences, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Identifiers
- 99900896440601842
- Language
- English
- Resource Type
- Thesis