ARS | Publication request: Calving traits of crossbred Brahman Cows are Associated with Heat Shock Protein 70 Genetic Polymorphisms

Submitted to: Animal Reproduction Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 5, 2010
Publication Date: February 12, 2010
Citation: Rosenkrans, C., Banks, A., Reiter, S., Looper, M.L. 2010. Calving traits of crossbred Brahman cows are associated with heat shock protein 70 genetic polymorphisms. Animal Reproduction Sciences. 119:178-182.

Interpretive Summary: Increased calving rate of the cowherd optimizes the profitability of beef producers. Use of genetic markers such as single nucleotide polymorphisms (SNP) can accelerate the selection of cattle that are more productive. Scientists from ARS in Booneville, AR, and University of Arkansas personnel identified SNPs in the promoter region of the bovine heat shock protein 70 (Hsp70) gene and evaluated the association of these SNPs with calving rates of Brahman-influenced cows. Polymorphisms of the promoter region of the Hsp70 gene were associated with calving rate, serum concentrations of Hsp70 and Julian calving date. These results provide information that suggests identification of cows with specific genotypes within the promoter region of Hsp70 gene can assist beef producers in selection of cows that may have increased fertility.

Technical Abstract: Objectives were to: 1) identify single nucleotide polymorphisms (SNP) located in the promoter region of the bovine heat shock protein 70 gene, and 2) evaluate associations between Hsp70 SNP and calving rates of Brahman-influenced cows. Specific primers were designed for PCR amplification of a 539 base segment of the bovine Hsp70 promoter (GenBank accession number M98823). Eleven single nucleotide polymorphisms were detected; eight transitions (G1013A, n = 2; G1045A, n = 8; C1069T, n = 4; A1096G, n = 14; G1117A, n = 12; T1134C, n = 7; C1154G, n = 11; and T1204C, n = 56), two transversions (A1125C, n = 53; and G1128T, n = 51), and one deletion at base position 895 (n = 37). Cows that were homozygous for the minor allele at both transversion (A1125C and G1128T) sites had lower (P < 0.05) calving rates when compared with cows that were homozygous for the primary allele. Homozygous and heterozygous deletion of cytosine at base 895 resulted in lower (P < 0.05) calving percentages than homozygous cytosine cows. In addition, homozygous deletion cows had the latest (P < 0.05) Julian calving date. Eighteen Hsp70 promoter haplotypes were deduced, and seven of those haplotypes (n = 37) included the deletion at base 895. Thirty-two cows had the haplotype consistent with the sequence deposited at GenBank, and the remaining 30 cows had a SNP other than the deletion. Cows with the deletion haplotypes had higher (P < 0.05) serum Hsp70 concentrations, lower (P < 0.05) calving rates, and the latest (P < 0.05) Julian calving date when compared with cows having other SNP haplotypes. The promoter region of the bovine Hsp70 gene is polymorphic and may be useful in selecting cows with a greater fertility.