EVALUATION OF THE GENETIC CONSERVATION PR OGRAMS FOR THE SHEEP BREEDSSOLOGNOTE AND MERIONS-PRECOCE

In order to preserve endangered domestic breeds, genetic conservation programmes based on circular mating systems were undertaken in the she ep breeds Solognote and Merinos precoce. The purpose of this study was to evaluate these conservation programmes. Demographic analysis indic ates that both the number of males and their replacement rate are high in accordance with the management rules. But progeny sizes are not al ways balanced. Genetic analysis was carried out using pedigrees. Compu tation of probabilities of gene origin shows an imbalance between the contributions of different flocks to the present pool of genes, especi ally in the Solognote breed, where the mating system is mainly built o n 2 flocks. Nevertheless, the various founder animals, as well as the reproduction groups from which they originated, contribute in a balanc ed way to the gene pool. The genetic programme prevents close inbreedi ng and restricts total inbreeding. In conclusion, the genetic conserva tion programmes were well implemented, in spite of practical problems, and were effective. Demographic decline, characterized by the decreas e of Population size and the increase of ageing, is now the main threa t for the future of these populations.