Date of Graduation

5-2018

Document Type

Thesis

Degree Name

Bachelor of Science in Agricultural, Food and Life Sciences

Degree Level

Undergraduate

Department

Animal Science

Advisor

Rosenkrans, Charles Jr.

Abstract

When eukaryotes are exposed to stressors such as heat, toxins, and low oxygen levels, heat shock proteins (HSPs) are synthesized to maintain normal cellular function within the body. Single nucleotide polymorphisms in the heat shock protein 70 (Hsp70) gene have been associated with calving percentage, and Julian calving date in spring-calving crossbred Brahman cows (Rosenkrans, et al., 2010). Our objective was to determine associations between previously identified polymorphisms in the promoter region and coding sequence of the bovine Hsp70 gene and beef cow efficiency. We evaluated productivity traits, including Julian calving date and calving rates, of fall-calving cows at each single nucleotide polymorphism (SNP) site. Genomic DNA was extracted from blood samples collected from crossbred cows (n=109) and amplified by polymerase chain reaction (PCR) using specific forward and reverse primers. Upon amplification, samples were purified, quantified, and sequenced in a commercial laboratory. Sequences were analyzed to determine SNP and genotypes were assigned to each of them. Production data of the cows from 2012-2014 were analyzed at each SNP site. Cows with CD genotype at C895D calved about one week later (P = 0.0001) and tended (P < 0.06) to have calves with lighter birth weights compared to cows with CC genotype. Genotype at G2033C affected (P < 0.02) weaning weight and cow efficiency. Genotype of a haplotype composite (No SNP, Deletion, and Yes SNP) affected (P < 0.02) Julian date and cow efficiency. Polymorphisms associated with the bovine Hsp70 gene were related to important cattle productivity characteristics. Selecting replacement cattle with known Hsp70 genotypes may result in herds that are more thermotolerant and sustainable.

Keywords

Cattle, Hsp70, Polymorphism, Productivity

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