Periparturient mortality in merino ewes in Australia: Incidence, impact and the path to mitigation strategies.

Abstract

Managing breeding ewe mortality is a priority for the Australian sheep industry. The periparturient period carries the highest risk of mortality, but the incidence and causes in Merino ewes are not well characterised. Here, we outline the reported incidence of annual and periparturient mortality for Australian Merino ewes, causes and risk factors for ewe mortality and current recommendations for managing periparturient ewes and gaps in the literature. The mean incidence of periparturient mortality reported in Merino ewes ranges from 0.3% to 11.4%. However, there are challenges with reporting mortality figures in extensive production systems due to the nature of record keeping and farm characteristics. Studies reporting causes of periparturient mortality indicate that these are typically multifactorial, with metabolic disease and dystocia likely to be important. Identifying potential mitigation strategies has the potential to improve productivity, profitability and welfare on Australian farms.