Liver fluke infection is a major parasitic disease of cattle and sheep causing chronic pain and production losses, with climate change expanding the geographic range of the parasite.
Chronic liver fluke disease causes prolonged suffering through progressive liver damage, anaemia, and the metabolic costs of sustained infection. Infected animals experience reduced appetite, lethargy, and pain from liver inflammation over extended periods before reaching clinical thresholds where farmers intervene. The subclinical phase of infection, during which animals appear outwardly normal but suffer internally, is the longest and most poorly managed welfare period. Pasture management to reduce snail habitat, strategic flukicide treatment based on disease risk modelling, and monitoring to detect early liver damage are the most effective welfare interventions. Resistance surveillance is increasingly important as treatment options narrow.