The α s1-casein is a protein polymorphism of goat milk first described in Europe, in the French Alpine and Saanen breeds, in the early nineteen eighties.

These polymorphisms have been found to affect cheesemaking due to differences in protein content, renneting properties (faster coagulation and firmer curd) and a possible connection in relation to cheese flavor.  In one study, the results of researches conducted on homozygous individuals for the various alleles confirmed the effects of genotype on the casein content in milk by showing the cheesemaking yield observed in milk produced by those animals with strong alleles was 7% higher in comparison with those with medium alleles and 15% higher than those with weak alleles.

Knowing the specific genetic polymorphism at goat casein loci on breeding stock would allow the breeder to set up breeding and selection programs targeted towards the improvement of cheesemaking yield by selecting for high expression alleles, or selecting for animals with low levels which may be of benefit to those with milk sensitivities.*

*Reprinted from the ADGA website.

Perhaps my favorite information regarding Alpha S1 Casein is from the American Kiko Goat Association quoting the Journal of Dairy Science, June 2007:

"Alpha s1 Casein is one of the four casein proteins found in goat's milk. The Alpha s1 Casein gene (CSN1S1) that produces the protein shows polymorphisms which affect the amount of protein and fat produced. DNA tests have been developed which can allow breeders to select production levels of Alpha s1 Casein.

This test has been utilized by the dairy goat industry for many years, in breeding strategies for developing goats with higher fat and protein content for cheese making, or lower fat and protein content for those who are “milk sensitive.”

From Characterization of the Casein Gene Complex in West African Goats and Description of a New αs1-Casein Polymorphism, Journal of Dairy Science, June 2007:

“. . . greater protein and casein content would increase the energy content of milk, thus resulting in more favorable growth and survival of young goats and humans consuming the milk.”"



"Goat Alpha S1 Casein"

Click on the link below to see this article.

https://www.vgl.ucdavis.edu/services/alphas1.php



"Effects on Production Traits of Haplotypes Among Casein Genes in Norwegian Goats and Evidence for a Site of Preferential Recombination"

Click on the link below to see this article.

http://www.genetics.org/content/174/1/455



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