Date of Graduation

8-2011

Document Type

Thesis

Degree Name

Master of Science in Animal Science (MS)

Degree Level

Graduate

Department

Animal Science

Advisor/Mentor

Rick W. Rorie

Committee Member

David L. Kreider

Second Committee Member

Charles F. Rosenkrans, Jr.

Keywords

Biological Sciences, Bull, Fertility, Osteopontin, Polymorphisms, Semen

Abstract

Two groups of bulls were utilized to evaluate if single nucleotide polymorphisms (SNP) in the Bos taurus OPN gene (GenBank accession # AY878328.1) promoter region were related to bull semen quality variables as evaluated by computer assisted semen analysis (CASA). Group 1 consisted of 19 Angus and Balancer bulls, ranging in age from 5 to 8 years, which were collected weekly during a 2-month period (July 15, 2010 through September 19, 2010). Group 2 consisted of 16 Brahman influenced (1/8 to 3/16 Brahman) bulls, mean age = 1.1 ± 0.1 year, that were collected monthly for a 7 month period (February 27, 2007 to August 16, 2007). Each collection was evaluated for motile, progressive, rapid, medium, slow, static, path velocity (VAP), progressive velocity (VSL), track speed (VCL), lateral amplitude (ALH), beat frequency (BCF), straightness (STR), linearity (LIN), elongation and area variables using CASA after semen collection. Each bull was genotyped for reported SNP in the promoter region of the OPN gene through PCR amplification of two 700 base pair fragments and sequencing of the resulting PCR product. Eight SNP sites were identified in Group 1 at base pairs 3379, 3490, 3492, 4967, 5075, 5205, 5209, and 5263 of the OPN gene and additional SNP at base pairs 3541, 3800 and 5262 in Group 2. Individual SNP sites were evaluated as the main effect on CASA measured variables in a SAS MIXED model for repeated measures. The SNP analysis found differences (P ≤ 0.05) within groups for motile, rapid, progressive, VAP, VCL, ALH, LIN and elongation variables. Haplotypes also were constructed and compared for differences in sperm variables. In Group 1, certain haplotypes appear to be more favorable for percent motile, progressive and rapid sperm, as well as VAP, VSL, VCL, elongation and total abnormalities than bulls identified with haplotype 1 (reported normal reference sequence). In Group 2, various differences were identified among haplotypes, but were only more favorable than haplotype 1 for BCF and live percentage. These results suggest that polymorphisms within the promoter region of the bovine OPN gene might be useful in certain populations for the selection of bulls with improved sperm quality.

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