Liver fluke (Fasciola hepatica) is a significant welfare concern in UK sheep and cattle, with climate change expanding the geographic range and season of infection risk.
Liver fluke welfare is both acute and chronic. Acute fluke disease in sheep causes sudden death from liver haemorrhage following heavy early infection. Chronic disease causes progressive liver damage, anaemia, bottle jaw (fluid accumulation) and wasting - suffering over weeks to months. Subclinical infection causes production losses and immune suppression without obvious clinical signs but with real welfare impact. Prevention through strategic grazing management (avoiding wet areas during high-risk periods, drainage of snail habitat) and targeted flukicide treatment based on risk assessment is more sustainable than routine treatment that drives resistance. Climate change makes liver fluke monitoring and risk assessment a year-round management priority rather than a seasonal concern.