Prevalence of αs₁-casein genotypes in American dairy goats

• Published in: Journal of animal science Vol. 87; no. 11; pp. 3464 - 3469
• Main Authors: Maga, E.A, Daftari, P, Kültz, D, Penedo, M.C.T
• Format: Journal Article
• Language: English
• Published: Champaign, IL American Society of Animal Science 01.11.2009
• Subjects: alleles; alphaS1-casein; Animal productions; Biological and medical sciences; breed differences; casein; coagulation; dairy animals; functional properties; Fundamental and applied biological sciences. Psychology; genotype; goat breeds; goat milk; goats; milk composition; milk proteins; prevalence; protein composition; Terrestrial animal productions; total solids; Vertebrates; United States; α; Milk protein; Vertebrata; Dairy animal; Mammalia; Prevalence; Casein; Genotype; Goat; Artiodactyla; Ungulata; Milk production
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/jas.2009-1854

Widespread genotyping of US dairy goat breeds for casein variants has not been reported, even though the genetic data could be of use in selective breeding programs. For instance, variability in the content of protein and solids in goat milk is attributed to allelic differences in the goat αs₁-casein gene. Concentrations of αs₁-casein in goat milk are positively correlated with milk components and coagulation properties. The alleles A and B are designated as strong alleles, resulting in the greatest amount of αs₁-casein in goat milk, whereas the E allele produces intermediate amounts and the weak allele F produces the least concentrations of αs₁-casein in goat milk. Here we report on one of the first surveys of the distribution of αs₁-casein genotypes in US dairy goats. The population surveyed, consisting of a total of 257 American dairy goats representing 7 main dairy breeds, contained a greater predominance of the weaker alleles, E and F, than the strong alleles, A and B. Allele distribution was related to breed, with Toggenburg, Alpine, Saanen, and Oberhasli containing the most E and F alleles and LaMancha, Nubian, and Nigerian Dwarf the fewest. Quantification of αs₁-casein production by 2-dimensional gel electrophoresis demonstrated that F/F animals had the least amount of αs₁-casein protein in their milk compared with all other genotypes. The results indicate that genetic improvement of dairy goats in the United States could be achieved if an αs₁-casein breeding scheme were adopted.