Genetic parameters for first lactation dairy traits in the Alpine and Saanen goat breeds

Abstract

Genetic parameters for dairy traits in first lactation (milk yield, fat and protein yields, fat and protein contents) were estimated by restricted maximum likelihood in the Alpine and Saanen goat breeds from records including progeny of 473 and 238 unproven bucks respectively, mainly used in natural mating. The differences between breeds could also be estimated when the flocks used both breeds. The sampling of the data sets, the addition of data from 28 and 22 progenies of Al proven sires, and the relationship matrix between sampling sires contributed to increase the connection level between flocks, which, however, remained rather low. In the same environmental conditions, particularly in the same year-flock, the Saanen breed appeared more high-yielding than the Alpine, but solid content was lower. Within-breed, the genetic standard deviation was 1.8-2 fold larger for fat content than for protein content. The heritability of fat and protein yields was rather high (0.31 to 0.39). The genetic correlations between yields were larger than 0.8. They were generally negative but rather low (-0.30 to +0.07) between milk yield and contents. They were clearly positive between fat yield and content (0.45 to 0.59), and between protein yield and content (0.14 to 0.29). They were close to zero and possibly positive between the yield of one component and the content of the other (-0.02 to +0.34). Some discrepancies with the average literature data need to be confirmed.