Farm Animal Welfare

Sheep Internal Parasite Resistance and Welfare

Nematode parasite resistance to anthelmintics is a growing welfare challenge in sheep farming globally.

Key Facts

Anthelmintic resistance in sheep roundworms is widespread in many sheep-farming countries
Resistant worms cause production losses and welfare harm through anaemia and weight loss
Refugia-based treatment strategies preserve anthelmintic efficacy by leaving some untreated animals
Genetic selection for parasite resistance in breeding rams improves flock resilience
FECRT testing identifies resistance patterns enabling more strategic treatment decisions

Welfare Considerations

Nematode parasite burden causes significant welfare harm in affected sheep through anaemia, weight loss, and in severe cases death. The erosion of anthelmintic effectiveness through resistance leaves farmers with fewer tools to address this welfare challenge. Refugia-based management and genetic selection are welfare-positive long-term solutions that also preserve treatment efficacy for cases where intervention remains necessary.

What You Can Do

Support refugia-based parasite management as a welfare and resistance preservation strategy
Advocate for genetic selection for parasite resistance in sheep breeding programmes
Learn about integrated parasite management approaches that protect both sheep welfare and anthelmintic efficacy