Overview and perspectives of the management of genetic diversity in French dairy sheep | Bilan et perspectives de la gestion de la variabilité génétique des ovins laitiers en France

National audience

anglais. Management of genetic diversity is a major concern in animal breeding, especially as genomic selection starting in French dairy sheep will reduce generation interval and increase genetic progress. Hence, it appeared important to assess the evolution of genetic diversity over the last decades using pedigree information to better monitor the breeding schemes. The results obtained in the Lacaune (LL) and Ref-Faced Manech breed (MTR) are satisfying: respectively + 0.29 and + 0.42 % of inbreeding increase per generation over 2000-2009, even though it is still possible to better balance elite families in MTR. On the contrary, results from Basco-Bearnaise (BB) and Black-Faced Manech breeds (MTN) underline a less efficient management of genetic diversity: respectively + 0.74 and + 1.02 % of inbreeding increase per generation over 2000-2009. This situation results from the too small number of sires of ram families (PAB) compared to the number allowed by the size of the nucleus of selection BB and MTN. This is a consequence of an imbalanced use of PAB families due to the very short duration of the AI period (fresh semen) and the lower AI fertility in these two breeds. Studies were carried out with the managers of breeding societies. This was done in order to increase the number of PAB families and to provide at each step of selection, the indicators of genetic variability allowing a more balanced management of these PAB families. Corse breed pedigrees are not extensive enough to allow a relevant pedigree analysis. Studies are on-going in these five breeds to assess genetic variability based on SNP (Single Nucleotid Polymorphism) from the 18,500 genotypes available with genomic selection.