EFFECTS OF THE ALPHA S1-CASEIN GENOTYPE ON MILK YIELD AND MILK COMPOSITION OF BALKAN GOAT IN MONTENEGRO

The objective of this study was to investigate genetic polymorphism of the alpha S1 casein gene and its association with milk production parameters (milk yield and milk composition) of indigenous Balkan goat breed reared in Montenegro. Two genetic variants (A and F) and three genotypes AA, AF and FF of alpha S1-casein have been identified. The analysis showed a prevalence of strong A allele (0.626) compared to the weak F allele (0.374), while the frequencies of genotypes were 0.398, 0.456 and 0.146 respectively. The effect of genotype of alpha S1 casein on the total milk yield, length of lactation and daily milk yield was not significant (p 0.05), while it is significantly influenced to the milk composition parameters. Goats with AA genotype of alpha S1 casein had significantly higher (p 0.001) average content of protein (3.54%) than AF and FF genotype (3.40% and 3.33%). The same genotypes order were for fat content and solid non-fat content (AA AF FF) with significant differences (p 0.05) of AA genotype in comparison to AF and FF. Genetic characterization of the alpha S1-casein gene contributes to the knowledge of the genetic structure of Balkan goat breed in Montenegro. These results could be important for establishing of the concept of conservation and sustainable use of this indigenous goat breed, as well as for selection scheme and breeding program.