EFFECT OF PRODUCTION SYSTEM, SEASON OF LAMBING AND SEX ON NEONATAL MORTALITY OF PELIBUEY LAMBS

Abstract

A study was conducted in Tecomán, Colima, México, with the objective to evaluate the influence of the production system (extensive, intensive), season of lambing (rainy, dry) and sex (male, female) on neonatal mortality of Pelibuey lambs. Cause of death, sex and occurrence season was recorded in both production systems and risk factors for neonatal mortality was analyzed by Logistic Regression.  Additionally, the prevalence of cause of mortality for production system, sex and season of year was determined and compared by Z test for proportions. The mortality rate in the extensive system was 30.96% whereas in the intensive system was 4.61%. Starvation was the main cause of mortality with a prevalence of 65.78 and 73.91% in both, extensive and intensive production systems respectively, with a low prevalence of loses for infectious diseases Lambs born under extensive conditions presented 9.75 more possibilities to die than those born under intensive conditions. Lambs born during the dry season and male lambs had 0.69 and .068 more possibilities to die than those born during the rainy season and females respectively. No effect between sex and season of year on mortality causes was observed in neither of the production systems under study.