Farm Animals

Sheep Internal Parasite Resistance Breeding

Breeding sheep with genetic resistance to gastrointestinal parasites reduces welfare impacts of worm burden while decreasing reliance on anthelmintics.

Key Facts

Gastrointestinal parasites cause the single greatest welfare and productivity loss in sheep
Haemonchus contortus (barber pole worm) kills thousands of sheep annually through anaemia
FAMACHA scoring of eye membrane colour identifies parasitised individuals for targeted treatment
Breeding values for worm resistance allow genetic selection based on faecal egg counts
Parasite refugia management preserves anthelmintic efficacy for welfare-critical cases

Welfare Considerations

Worm burden causes progressive welfare deterioration through anaemia, protein loss, and eventual death. Genetic approaches that build animal resilience reduce both individual suffering and population-level anthelmintic dependency with long-term welfare benefits.

What You Can Do

Ask your sheep breed society about estimated breeding values for parasite resistance
Learn to use FAMACHA scoring for targeted anthelmintic treatment
Implement refugia-based dosing to preserve drug efficacy
Support research into alternative parasite control including vaccines