Pedigree analysis of the French dairy cattle breeds

Abstract

This paper presents an overview of the genetic variability of the 8 main French dairy cattle breeds, estimated through pedigree information. The Normande and Tarentaise breeds are closed populations, the Montbéliarde and Abondance breeds recently introduced a limited amount of Red Holstein genes, whereas the Holstein, Brown Swiss, Pie Rouge des Plaines, and Simmental populations widely use foreign germplasm, sometimes until complete absorption. The estimation of inbreeding is strongly dependent on the population structure and on the quality of the pedigree information. When inbreeding can be correctly estimated, its level is found to increase by about 1 % per generation, and the realized effective size is close to or less than 50. The effective number of ancestors, derived from the probabilities of gene origins, varies from 17 to 64 according to the breed and is not related to the number of females in the population. Due to the efficiency of artificial insemination, the dairy cattle breeds are genetically small populations. Further investigations are needed to propose selection methods more favorable to the preservation of genetic diversity but still compatible with the selection programs. Two urgent proposals are to maintain all existing populations and to increase the number of bull sires in the breeds with the largest number of females.