Genetic Diversity and Population Structure of Sardo Negro Cattle

Livestock production in Mexico takes place in a wide range of agroecological regions, with approximately one-third of the cattle population raised under tropical conditions, where heat stress and disease pressure limit the performance of poorly adapted animals. The Mexican Sardo Negro cattle breed (<i>Bos indicus</i>) is environmentally resilient and is used for both meat and milk production; however, information regarding its population structure and reproductive management remains limited. Therefore, the genetic diversity and population structure of this breed were evaluated through pedigree analysis to support conservation strategies. Genealogical records from 8653 animals belonging to six herds located in the states of Veracruz and Chiapas, Mexico, were analyzed using ENDOG V4.8, PopRep and GRain software. The average inbreeding coefficient was 2.5%, with an increase of 0.9% per generation, a mean generational interval of 7.9 years, and a maximum pedigree depth of nine generations, although pedigree completeness was low in distant generations. The difference between the effective number of ancestors (32) and founders (37) suggests the absence of bottlenecks; however, the fact that only 21 individuals account for 50% of the genetic variability is indicative of a founder effect. Overall, the population exhibits an acceptable level of inbreeding, highlighting the importance of planned mating strategies to maintain genetic diversity and ensure the long-term conservation of the Sardo Negro breed.