Population structure and demographic trends of the registered Sahiwal cattle in Kenya

Abstract

Sahiwal cattle breed is an important genetic resource that supports livelihoods of pastoralists in Kenya. However, information about its population structure, demographic trends, and genetic diversity is scarce. The objective of this study was to characterize the population structure, explore demographic trends, and evaluate genetic diversity parameters of the breed through pedigree analysis. Pedigree data from National Sahiwal Stud and Kenya Stud Book were combined and analyzed using POPREP software package. The number of registered breeding animals indicated a downward trend over time. Generation interval was longer by 3 years in males than in females. Average inbreeding coefficient was 0.58 % for all animals and 2.23 % for inbred animals. Average inbreeding between 1960 and 2008 for inbred animals decreased at −0.0012 % per year while for the entire breed increased at 0.025 % per year. Additive genetic relationship in the whole population was 0.87 %. The effective population size declined over time and was lower than that recommended to maintain genetic diversity in the long term. The breed was found to be losing genetic diversity over time, and therefore a strategy to reduce inbreeding rate and increase effective population size is recommended.