Population viability analysis of the Crioula Lageano cattle

The aim of the present work was to perform a population viability analysis of the Crioula Lageana cattle breed to study its demographic and genetic parameters, as well as to verify the interference of factors that may affect the survival and development this population. Population viability was estimated using 128 hypothetical scenarios to assess the risk of extinction of this genetic resource, simulated over a 500 year period. The results showed that the possibility of extinction of this breed over the next 500 years was remote, even in less favourable scenarios. The deterministic growth rate was always positive during the evaluated period, and the mortality of animals up to one year of age was the most important factor that affected this parameter. The population size increased rapidly until the carrying capacity (k) was reached, which was a limiting factor for population growth. The level of retained heterozygosis in the population in the worst scenario was above 80% and the inbreeding coefficient was always below 0.20 at the end of the 500 years of simulation. The analysis of the population viability showed that the Crioula Lageana population has no long-term risk of extinction, and the carrying capacity is the main limiting factor for population growth.