RISK-FACTORS ASSOCIATED WITH POSTPARTUM DEATHS IN EARLY BORN, HOUSED LAMBS IN SOUTHWEST ENGLAND

The mortality of lambs was recorded in three early lambing, housed flocks in southwest England. Total mortality in the 2 year period ranged from 7.7 to 11.7%. The greatest risk of death occurred during parturition and in the first week after birth (4.2-9.7%). Factors associated with death in this period have been described elsewhere. In lambs over 1 week old there were flock differences in the proportion of deaths and the diseases observed. The most frequent causes of death included focal abscessation (liver, lung, umbilicus, joint, spine), enteric and neural infections, anaemia and cerebrocortical necrosis (CCN). Diseases were observed to follow specific age patterns. Multiple logistic regression indicated that there was an increased odds of death postpartum as birth weight decreased, in male lambs compared with females, as litter size increased (with the exception of triplets) and as preweaning daily live weight gain decreased. The odds of dying were also associated with the flock of origin.