Kappa-casein

Quick Summary

Kappa-casein is an important gene for protein yield and percentage in milk. Two common variants, A and B, are associated with different concentrations of kappa-casein protein in cow's milk.

Red and white cow in field with milk jug in foregroundPhenotype: The gene underlying the production of kappa-casein in cow's milk shows polymorphisms which affect the amount of protein produced. Higher levels of kappa-casein are associated with increased milk protein and casein content, and better cheese yield.

Variants:

  • A = associated with lower relative concentration of kappa-casein in milk
  • B = associated with higher relative concentration of kappa-casein in milk

Breeds appropriate for testing: Many dairy breeds

Explanation of Results:

  • Cows with AA genotype will produce lower amounts of kappa-casein in their milk; least favorable genotype for cheese production.
  • Cows with AB genotype will produce intermediate amounts of kappa-casein in their milk.
  • Cows with BB genotype will produce higher amounts of kappa-casein in their milk; most favorable genotype for cheese production.
Price

$25 one test per animal

Panels Available
Additional Details

Cow's milk is comprised of six main proteins: four types of casein (including beta-casein and kappa-casein) and two types of whey protein (beta-lactoglobulin and alpha‐lactalbumin). Kappa-casein is an important gene for protein yield and percentage in milk.

This test identifies the two most common kappa-casein variants, A and B. The A variant and AA genotype are associated with higher milk production. The B variant and BB genotype are associated with increased milk protein and casein content, and better cheese yield. Relative to protein content and cheese production, BB is the most favorable genotype, AB is intermediate, and AA is the least favorable.

 

Other dairy milk protein tests offered by the VGL:

Turnaround Time
5-10 business days
Type of Sample

Species

Type of Test

References

Medrano, J.F., & Aguilar-Cordova, E. (1990). Genotyping of bovine kappa-casein loci following DNA sequence amplification. Biotechnology, 8, 144–146. [PMID: 1369440]

Rincón, G., & Medrano, J.F. (2003). Single nucleotide polymorphism genotyping of bovine milk protein genes using the tetra-primer ARMS-PCR. Journal of Animal Breeding and Genetics, 120, 333-337. doi: 10.1046/j.1439-0388.2003.00405.x

Hållén, E., Wedholm, A., Andren, A.H., & Lundén, A. (2008). Effect of beta-casein, kappa-casein and beta-lactoglobulin genotypes on concentration of milk protein variants. Journal of Animal Breeding and Genetics, 125(2), 119-129. doi: 10.1111/j.1439-0388.2007.00706.x