title: Polymorphism of caprine milk alphas1-casein in relation to performance of four Polish goat breeds.
abstract: Polymorphism of goat milk alphas1-casein was determined and potential relations between genetic variants of this protein fraction and goat performance were evaluated. The investigations were performed on 598 goats assigned to of 4 breed groups (White improved 254 units, Coloured improved--124, White non-improved--146 and Coloured non-improved--74). For each goat, alphas1-casein polymorphism was determined in polyacrylamide gel by the PAGE-SDS method and percentage of milk alphas1-casein and gene frequency established. There was evaluated goat performance at successive lactations. In the goat population investigated, AA, AB, BB, AE, BE and EE alphas1-casein genotypes were identified. In all four breeds, alphas1-casein genotype EE clearly predominated (27.2-39.2%), recognized as "medium" and its share was higher in the groups of non-improved goats. It was conditioned by high frequency of gene E alphas1-casein (0.419-0.622). Generally, EE genotype percentage was higher in the non-improved goat groups. The improved goats, though, obtained higher productivity in each of the lactation studied. Analysis of relationships between alphas1-casein genetic variants and goats performance confirmed a significant influence on milk, protein and fat yields only in the Coloured improved goat group. There was revealed a more general tendency indicating a significant impact of "strong" alphas1-casein genotypes on a concentration of basic milk components, i.e. fat and protein, especially casein. In a group of goats producing milk of the highest casein content (over 2.4%) and protein (over 3.0%), the animals showing "strong" alphas1-casein variants dominated (85 and 70 %).
authors.affiliation: Department of Animal Raw Material Commodity Science and Processing, Agricultural University, Akademicka 13, 20-950 Lublin, Poland. joanna.barlowska@ar.lublin.pl
authors.forename: J
authors.initials: J
authors.lastname: Barłowska
authors.forename: Z
authors.initials: Z
authors.lastname: Litwińczuk
authors.forename: M
authors.initials: M
authors.lastname: Kedzierska-Matysek
authors.forename: A
authors.initials: A
authors.lastname: Litwińczuk
mesh_terms: D000818:Animals; D002364:Caseins / Q000235:genetics*; D005838:Genotype; D006041:Goats / Q000145:classification* / Q000235:genetics*; D008892:Milk / Q000737:chemistry; D011044:Poland; D011110:Polymorphism, Genetic
chemical_list: D002364:Caseins