Sheep Welfare: Liver Fluke Disease and Emerging Resistance

Fasciolosis (liver fluke) causes significant welfare suffering in sheep and cattle, with anthelmintic resistance threatening control options.

Key Facts

Fasciola hepatica, the liver fluke, is transmitted via aquatic snails in wet habitats
Acute liver fluke causes sudden death in young naive sheep in autumn
Chronic fluke causes weight loss, anaemia, bottle jaw, and production loss
Triclabendazole resistance is now confirmed on UK sheep farms
Climate change is expanding the seasonal and geographic risk period for fluke

Welfare Considerations

Sheep with acute fasciolosis die rapidly from liver haemorrhage in what is a painful terminal event. Chronically infected sheep suffer progressive liver damage, anaemia, and severe weight loss over months. Bottle jaw (submandibular oedema) indicates severe protein loss and systemic disease. Welfare-responsible fluke management includes strategic treatment at appropriate times, pasture management to reduce snail habitat, and rotation of anthelmintic classes to delay resistance.

What You Can Do

Advocate for faecal egg count and ELISA monitoring to guide strategic fluke treatment
Support responsible fluke treatment programmes that preserve anthelmintic efficacy
Encourage drainage of high-risk wet pasture areas
Back SCOPS (Sustainable Control of Parasites in Sheep) guidance adoption
Choose lamb from farms with documented parasite management protocols