Infectious abortion causes significant welfare harm in ewes and represents pregnancy loss at an advanced stage, with biosecurity and vaccination programs providing effective prevention.
Infectious abortion causes welfare harm at multiple levels. The aborting ewe experiences the physiological stress of pregnancy loss and may develop systemic infection causing fever and illness. Ewes that develop enzootic abortion placentitis are not just losing their current pregnancy but often become persistently infected carriers. The welfare impact of abortion storms affecting large proportions of a flock simultaneously is significant at the herd level. Specific welfare concerns include the zoonotic risk to pregnant farm workers and family members who may be exposed to aborting ewes. Vaccination programs and appropriate biosecurity substantially reduce these harms.