Kappa-casein (CASK)

Kappa-casein is a protein belonging to the casein group, the most abundant group of proteins in milk. It plays a key role in the process of milk coagulation, so directly on its structure depends the quality of the resulting curd, from which cheeses known as one of the basic dairy products are made. In order to get the best protein content and quality, genetic conditions must be taken into account.

The kappa-casein protein depends on a variant of the CSN3 gene, which in the cattle population is characterized by the occurrence of three alleles A, B, E. Allel A is the basic variant, and B is the most preferred one due to its favorable effect on the shortened time of the coagulation process, increased curd quality and cheese yield. Polymorphism of kappa-casein, depending on the frequency of alleles, allows the creation of a variety of genotype compositions. The most favorable genotype is a set of two variants B – BB, showing the best milk coagulation properties. However, other genotypes consisting of at least one B allele are very important for further genetic determinants of generations, as they allow to increase its frequency in offspring.

The occurrence of kappa-caesin polymorphism has been demonstrated in different breeds of cattle: Lineback, Devon, Ankole-Watusi, Ayrshire, Beefmaster, Belgian Blue, Brown Swiss, Dexter, Dutch Belted, Gir, Guernsey, Holstein-Friesian, Jersey, Kerry, Maine-Anjou, Montbeliarde, Normande, Norwegian Red, Piedmontese, Pinzgauer, Red & White, Salers, Shorthorn, Simmental.

REFERENCES #

1. Gabche A. E. Epse Laisin, Adedibu I. I., Kabir M. & Iyiola-Tunji A.O. Effect of Polymorphism of Kappa Casein Geneon Milk Yield and Composition Traits in Friesian X BunajiCows. (2021). Journal of Research in Agriculture and Animal Science 8 (8), 14-21.
   
2. Lavon Y., Weller JI., Zeron Y. & Ezra E. Estimating the Effect of the Kappa Casein Genotype on Milk Coagulation Properties in Israeli Holstein Cows. (2023). Animals (Basel) 22;14(1):54.