Livestock

Internal Parasite Management in Sheep: Welfare and Resistance

Gastrointestinal parasites are the most significant health and welfare challenge in UK sheep farming, and resistance to anthelmintic drugs is making conventional treatment increasingly ineffective.

Key Facts

Haemonchus contortus and Teladorsagia circumcincta are the primary pathogenic species
Drug resistance to all three anthelmintic classes is widespread in UK flocks
Targeted selective treatment based on FAMACHA scoring and FEC reduces resistance selection
Refugia-based approaches preserve susceptible parasite populations to dilute resistance
SCOPS programme provides evidence-based guidance for sustainable parasite control

Welfare Considerations

Sheep infected with parasites suffer from anaemia, protein loss, weight loss, and reduced immune function. Severe Haemonchus infection can cause rapid death. As drug resistance increases, effective treatment options narrow, meaning welfare suffering from parasitism will increase without improved management. Surveillance and rational treatment are essential.

What You Can Do

Implement SCOPS-recommended parasite control programme for your flock
Use targeted selective treatment based on FAMACHA or FECRT rather than blanket dosing
Test anthelmintic efficacy through drench checks at least every 3 years
Reduce refugia destruction by treating only animals that need it
Consult your vet or SCOPS-trained nutritionist on sustainable parasite management