Heritability Estimates of Stillbirth and Preweaning Mortality in a Zebu Population of Southeastern, Mexico

摘要

The objective of this study was to estimate the heritabilities of stillbirth and preweaning mortality in a Zebu herd in the tropics of Mexico. The data collected were for cows calving over a 21 years period (1989-2009). The base population was commercial Zebu cattle. The model included the fixed effects of period of year, season of birth, parity number, breed of sire and the random effects of sire within sire breed and the error term. Mean heritability estimates and standard deviations for stillbirth and preweaning mortality from posterior distributions were 0.030±0.020 and 0.031±0.025, respectively. The low heritability here found also suggested that environmental factors are more important than genetic effects on those traits. Therefore, the potential for selective improvement of stillbirth and preweaning mortality appears to be limited to long-term programs and that the control of various management and risk factors would have more immediate effect.