Farm Animal Welfare

Farmed Sheep Internal Parasite Resistance and Welfare

Anthelmintic resistance in sheep nematodes is a major emerging welfare challenge requiring strategic management.

Key Facts

Resistance to all three major anthelmintic classes is now widespread in UK sheep nematodes
Haemonchus contortus causes rapid anaemia and death and has widespread multi-drug resistance
Targeted selective treatment using FAMACHA eye scoring treats only animals requiring medication
Refugia-based management maintains susceptible parasite populations to dilute resistance genes
Genetic selection for worm resistance in sheep breeds offers a long-term solution

Welfare Considerations

Parasitic gastroenteritis causes chronic suffering - weight loss, anaemia, protein loss and death in severe infections. Anthelmintic resistance threatens the ability to treat sick animals effectively. Strategic approaches including refugia management and targeted treatment protect both animal welfare and treatment efficacy for future generations.

What You Can Do

Work with your veterinarian to implement strategic parasite management on sheep farms
Support breeding programmes selecting for natural worm resistance in sheep
Advocate for anthelmintic stewardship guidelines as standard in sheep health plans
Support research into novel parasite control strategies for resistant populations