Genotype at the αen-casein locus and selection of bucks on progeny test in the Alpine and Saanen breeds

Abstract

A retrospective study on 184 Alpine and 96 Saanen bucks born between 1987 and 1990 indicates that the fractions of bucks selected after progeny testing depended on the αs1-casein genotype. In these breeds, the αs1-casein locus exhibits 3 strong allèles (pooled under the A designation), 2 week alleles (E and F), and one null allele (O). In the Alpine breed, current selection criteria resulted in 49% of AA bucks retained after progeny testing. Corresponding figures for the genotypes AE, AF, AO and bucks not carrying the strong allele A are 30%, 28%, 0% and 0%, respectively. In the Saanen breed, percentages of bucks retained after progeny testing were 44%, 36% and 18% for the genotypes AE plus AF, EE, and EF plus FF, respectively. These results highlight the value of typing young bucks in order to avoid progeny testing of males not carrying strong alleles at the αs1-casein locus. © 1995 Elsevier/INRA.