|SALES, MARITES - University Of Arkansas|
|LARSON, MELINDA - Louisiana State University|
|REITER, SARAH - University Of Arkansas|
|BROWN,JR, A - University Of Arkansas|
|COFFEY, KEN - University Of Arkansas|
|ROSENKRANS, JR, CHARLES - University Of Arkansas|
Submitted to: Journal of Animal Physiology and Animal Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/2011
Publication Date: N/A
Interpretive Summary: Small changes in the nucleic acid sequence of DNA within genes of cattle (single nucleotide polymorphisms or SNP's) might be related to differences in productivity in beef cows. A study was done to identify and relate SNP's in the cytochrome P450 3A28 gene (CYP3A28) in beef cattle to production traits. A cytosine (C) to guanine (G) transversion at base 994 (C994G) in CYP3A28 was identified so that three genotypes occurred in the cows studied: CC, CG, and GG.Cows with genotype CC grazing bermudagrass had greater milk protein that CG or GG but genotype CC cows on endophyte-infected tall fescue had similar milk protein to CG and GG genotypes. Cows with CC genotype in moderate body condition score (a measure of fatness) and GG genotype cows in low body condition score tended to calve earlier compared to CG genotype cows in low body condition score. In this study, genetic alterations (G allele at C994G) coupled with nutritional factors (low body condition score and toxic tall fescue) resulted in overall lower productivity in beef cows.
Technical Abstract: Relating single nucleotide polymorphisms (SNP) to cows with acceptable productivity could benefit cattle breeders especially in areas where tall fescue is the predominant forage. This study aimed to 1) identify SNPs in bovine cytochrome P450 3A28 (CYP3A28) and 2) determine associations between SNP genotype, forage, and cow body condition (BC). Genotype (CC, CG, or GG) and forage (Kentucky-31 wild-type endophyte-infected tall fescue [KY+] vs. bermudagrass) effects on milk volume and quality were determined in Herd 1 cows (n = 123); in Herd 2 (99 cows), genotype and BC (low vs. moderate) effects on ovarian follicle size, calving date, and calving percent were determined; and in Herd 3 (n = 114), effects of genotype and fescue cultivar (KY+ vs. non-toxic endophyte-infected tall fescue [HiMag4]) were related to calving percent, calving date, and weaning weights of both cow and her calf. A cytosine (C) to guanine (G) transversion at base 994 (C994G) in CYP3A28 was identified. There was a genotype x forage type effect (p < 0.05) on milk protein percent in Herd 1 cows; CC cows grazing bermudagrass had greater milk protein percentage compared to other cows in the herd. In Herd 2, BC and genotype x BC tended (p < 0.10) to influence follicle size and Julian calving date, respectively. Diameter of the largest follicle tended to be larger in moderate BC than low BC cows; whereas, CC cows in moderate BC and GG cows in low BC tended to calve earlier compared to CG cows in low BC. In Herd 3, there was a genotype x forage type effect (p < 0.05) on calving percent, Julian calving date, and calf weaning weight. In this study, genetic alterations (G allele at C994G) coupled with nutritional factors (low BC and toxic tall fescue) resulted in overall lower productivity in cows.