Culling and mortality in large dairy goat herds managed under intensive conditions in western France
Résumé
This study describes the flows of culled and dead goats in connection with the reasons for culling and the health disorders associated with mortality in 43 large intensive dairy goat herds of Western France. It also aims to characterize the reason-specific culled or dead goat profiles related to herd-life economic efficiency. Data regarding age at last kidding and culling or mortality, milk yield at the first two test-days of the final lactation and reason(s) for exit (culling and mortality) were collected in two 2-year surveys, carried out from 1992 to 1996, resulting in 4444 recorded exits. Polytomous logistic regression was used to assess relationship between age, kidding-to-exit interval, milk yield and five groups of exit reason (i.e. mortality, culling for voluntary reason, infertility, health reason, age). In the whole goat population studied, the proportions of exits, for each of these group of reasons, were 36.6, 14.5, 20.2, 6.4 and 22.3% respectively. On herd level, very different patterns of exit reason specific flows were described in a 7-class cluster analysis. Compared to the distribution of culling for voluntary reasons, mortality and culling for health reasons appeared to be more frequent in the higher yielding goats, in the earliest stages of lactation as well as in the last stages of lactation/pregnancy. Mortality appeared also to be more frequent in the younger class of goats