Infectious abortion in sheep from Chlamydophila abortus and Campylobacter species causes significant welfare harm to ewes and represents a major production and public health challenge in sheep farming.
Infectious abortion causes acute welfare harm to ewes through the physical process of abortion and associated illness. Ewes that abort late in pregnancy may have difficulty expelling compromised fetuses requiring assistance. Retained placenta following abortion causes uterine infection and systemic illness. Weak surviving lambs require intensive nursing and often die despite intervention causing additional welfare burden on farm staff. Preventing abortion through vaccination in known-risk areas and robust biosecurity for newly purchased sheep is far more effective than managing outbreaks. The zoonotic risk to pregnant humans on farms makes prevention a human health priority as well as an animal welfare one.