Genetic diversity of bovine populations raised in Senegal

Background: The Gobra zebu and N'dama tau rine cattle breeds are important genetic animal resources for Senegal. For several decades, genetic breeding programmes have been devoted to them at the Centre de Recherches Zootechniques de Dahra and Kolda. Since then, these animals have been subjected to mass selection, mainly in closed selection nuclei. Objective: This study aims to assess the genetic diversity within these selection nuclei in order to orient future selection strategies. Material and methods: The study was carried out on the Gobra zebu and N'dama taurine populations from selection nuclei of Dahra and Kolda respectively, which were compared to 5 other populations of the main cattle breeds in Senegal. One hundred eighty (180) animals were genotyped with 21 microsatellite markers recommended by the Food and Agriculture Organisation. Results: All populations were found to be polymorphic with a PIC of over 55%. However, animals from the CRZ-Dahra (indigenous) and CRZ-Kolda stations had the lowest mean heterozygosity (0.643 and 0.591 respectively). The other populations had an average heterozygosity between 0.650 and 0.737. Conclusion: The cattle populations maintained at the different CRZs show a lower genetic diversity than the other populations described in our study. The main reasons for this are reproductive isolation and selection pressure on these populations.