Effects of the αen-casein locus on dairy performances and genetic parameters of Alpine goats

Abstract

The influence of the αs1-casein polymorphism on dairy performance was studied on 883 lactations of Alpine goats at the Station caprine de Moissac in France. Genotype effects, heritabilities and genetic correlations were estimated using an animal model which included the effects of kidding date, year, lactation number, αs1-casein genotype (AA, AE, AF, EE, EF, FF), permanent environment and additive genetic value. The strong allele A affected significantly (P < 0.01) the true protein content (AA > AE, AF > EE, EF > ff) and the fat content (AA, AE, AF > EF and FF). AA goats produced less milk yield than AE, AF, EE and EF goats (P < 0.01). Genotypes AA, AE, AF and EE produced more protein yield than FF (P < 0.01). Heritabilities of protein content with and without including the αs1-casein genotype in the model, were 0.34 and 0.66, respectively. Including the αs1-casein genotype in the model also modified the genetic correlations between protein yield and protein content (-0.22 vs 0.09) and protein and fat contents (0.35 vs 0.45). This study confirms that the strong allele A is beneficial for improving goat milk quality. Moreover, previous results indicate that A is associated with higher casein/protein ratio and beneficial physico-chemical characteristics for cheese-making. We thus recommend use of αs1-casein polymorphism in goat selection. © 1995 Elsevier/INRA.