Genetic association analysis reveals significant effect of β-casein A1/A2 loci on production & reproduction traits in Frieswal crossbred cows

ABSTRACT

Milk β-casein has attracted extensive research interest in the dairy industry and animal breeding as a source of high-quality protein for human diet; however, adverse health effects have been ascribed to A1 β-casein variant consumption. A study was conducted to genotype the polymorphism in milk β-casein gene and examines the potential association between β-casein genotypes and milk production and reproduction traits in population of Frieswal cows. β-Casein A1/A2 genotype had significant effect (P ≤ 0.05) on several production traits including Total Milk Yield (TMY) (P ≤ 0.05), Milk Milk yield 300 days (MY300) (P ≤ 0.05), Lactation Length (LL) (P ≤ 0.01) and Peak Yield (PY) (P ≤ 0.01). β-Casein A1A1 genotype cows had significantly lower TMY, MY300, PY and DP as compared to A1A2 and A2A2 genotypes. A1A2 genotype had highest TMY, MY300, PY and DP; however, A2A2 and A1A2 genotypes were not significantly different from each other. The results pointed towards the superiority of A2 β-casein variant for several production traits in crossbreds. Further, with higher price of A2 milk, the inclusion of β-casein A1/A2 genotype in the selection of crossbreds offers higher profitability from dairy enterprise as well as provides a nutritional wellness product for consumers.

KEYWORDS:

• Beta-casein
• A1/A2
• association
• milk production
• pre-sleep
• crossbred

Acknowledgments

The authors sincerely acknowledge the help and support in the form of funds and important facilities provided by the Director and Joint Director (Research), ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, India, to perform this research. The authors also acknowledge director, Military Farms and Frieswal project, as well as officer in-charges of Military Farms (Bareilly and Lucknow) for biological samples and data.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The study was funded by ICAR- Indian Veterinary Research Institute, Izatnagar, Bareilly, India conducted under the approved project ‘Investigation on association between A1/A2 variants of β- Casein gene and economic traits in indigenous and crossbred cattle’.