Genetic characterization of some selected east african indigenous cattle

Abstract

The indigenous cattle breeds of Kenya have special adaptations (resistance to diseases, utilization oflow quality feeds and surviving under high tropical temperatures). There is a risk of loosing these unique adaptive features. The loss arises from increased market demands for animal products (such as milk) which leads to crossbreeding and replacement of indigenous breeds with high producing breeds. Compounded by the lack of knowledge of their genetic characteristics, an urgent plan to conserve and manage Kenya indigenous cattle genetic resources is required. This study was undertaken to determine the genetic diversity and relationships as well as assess the evidence of exotic blood influence on Teso (n = 44) and Winam (n = 50) indigenous cattle populations from western Kenya. Three reference populations were included in the study: Friesian, n = 20 (European Bas taurus), N'Dama, n = 34 (African Bas taurus) and Boran, n = 32 (Bas indicus). Genotyping was done using V-Chromosome specific Marker (INRA124) and 12 autosomal micro satellite DNA markers. The expected heterozygosity (HE) and observed heterozygosity (Ho) results indicated that Winam and Teso cattle populations were generally outbred (HE: Winam = 0.708, Teso = 0.723; Ho: Winam = 0.662, Teso = 0.670). There was insignificant genetic distance (DA = 0.035) and gene differentiation (FsT = 0.000) between Teso and Winam cattle populations (P:::; 0.05). No significant correlation between genetic and geographical distances was detected among Winam and Teso cattle populations. Admixture estimates and Y-chromosome DNA analysis results indicated evidence of introgression of exotic cattle blood into Teso (~ 8%) and Winam (~ 8%) indigenous cattle populations. In conclusion, Winam and Teso indigenous cattle populations can be considered as a single breeding unit as opposed to community based naming which classifies them as different populations.