Genetic Diversity and Population Structure of Sardo Negro Cattle

Livestock production in Mexico takes place in a variety of agro-ecological regions, with a third of cattle raised in the tropics (28% of the country), where environmental conditions cause heat stress and the development of diseases in unadapted animals. Animals of the Mexican Sardo Negro breed (Bos indicus) are environmentally resilient and used for meat and milk production. Little information is available on their breeding management. Therefore, their genetic diversity and population structure will be characterised using pedigrees. In 6 herds dedicated to this breed in Veracruz and Chiapas, Mexico (8,653 head), the coefficients explaining their diversity and population structure were obtained using ENDOG V4.8, PopRep and GRain software. The result was an average inbreeding of 2.5%, with an increase of 0.9% per generation, a generation interval of 7.9 years, with a maximum of 9 generations traced, and low pedigree completeness in the most distant generations. The difference between the effective number of ancestors (32) and founders (37) indicates the presence of bottlenecks. Only 21 individuals explain 50% of the genetic variability. There is an acceptable level of inbreeding, which can be improved in subsequent generations to contribute to its conservation.