A study on associations between PrP genotypes and meat traits in French sheep breeds

In this study the potential association of PrP genotypes with meat traits has been investigated. The data included young rams from individual testing stations of three breeds : lle de France, Prealpes du Sud and Blanc du Massif Central. These breeds were chosen due to their large number of available animals (with performance records and PrP genotypes) and their differential ARR haplotype frequency. Two analyses differing in the PrP genotype classes considered were carried out. Firstly, animals were categorized into three classes : ARR homozygous, ARR heterozygous, and animals without the ARR haplotype. The data for this analysis included 725, 534 and 832 animals for Ile de France, Prealpes du Sud and Blanc du Massif Central breeds, respectively. Secondly, as the two predominant haplotypes in these breeds are ARR and AR-(and AR- includes ARQ and ARH haplotypes), the effect of substituting 1 or 2 ARR haplotypes for AR- haplotypes was studied. These comparisons involved three genotype classes : ARR homozygous, ARR/AR-, and AR- homozygous. The data for this analysis included 532, 509 and 620 animals of Ile de France, Prealpes du Sud and Blanc du Massif Central breeds, respectively. Meat traits were analysed using an animal model (where the PrP genotype was included as a fixed effect) and they included growth rate, ultrasonic fat depth, and ultrasonic muscle depth. The results of this study indicate no evidence of association between PrP genotypes and the meat traits studied in these sheep breeds.