Modeling preslaughter mortality of broiler chickens using double generalized linear models

Abstract

The aim of this study was to estimate parameters and design models for mortality prediction of broiler chickens in different preslaughter conditions, using the double generalized linear models. Preslaughter data from 13,937 broiler flocks were recorded daily during 2006, in a commercial slaughterhouse in Brazil. Several factors which influenced mortality rate were analysed, such as daily mean dry-bulb temperature and relative humidity, lairage time, daily periods, density of broilers per crate and season of the year. The data were analysed using a Double Generalized Linear Model, an extension of Generalized Linear Models (GLM), which provides a framework for modeling the dispersion in generalized linear models as well as the mean. As results, the double generalized linear models showed high accuracy for broiler mortality estimation, through interactions between the main factors which have influence on preslaughter operations.