Farm Animals

Farmed Sheep Internal Parasite Genetic Resistance

Breeding sheep with genetic resistance to internal parasites reduces reliance on anthelmintic treatment and improves long-term flock welfare.

Key Facts

Faecal egg count (FEC) at challenge is heritable and used as a selection criterion
Breeds including Texel and Lacaune show higher innate parasite resistance
Estimated breeding values for FEC help identify resistant breeding stock
Resistant sheep require fewer anthelmintic treatments reducing drug resistance development
Nutrition also influences immune resistance to parasites

Welfare Considerations

Sheep with genetic resistance to internal parasites experience lower parasite burdens with fewer treatments, improving both welfare and antimicrobial stewardship. Breeding for resistance is a long-term investment that pays welfare dividends across generations. Combining genetic selection with targeted selective treatment maximises welfare gains.

What You Can Do

Support sheep breeding programmes using parasite resistance selection criteria
Advocate for breed society inclusion of parasite resistance EPDs
Choose lamb from farms using resistance-selected genetics