Farm Animal Welfare

Sheep Internal Parasite Management and Anthelmintic Resistance

Anthelmintic resistance in sheep worms is a growing crisis threatening welfare, with strategic management needed to preserve drug efficacy.

Key Facts

Resistance to all major drug classes is now found on most sheep farms
Haemonchus contortus causes rapid blood loss and can kill sheep within weeks
FAMACHA scoring assesses anaemia to target treatment to most affected animals
Refugia-based management preserves susceptible worm populations to dilute resistance
Genetic selection for parasite resistance offers long-term solutions

Welfare Considerations

Gastrointestinal worm burdens cause progressive suffering including anaemia, poor growth, bottle jaw, and death. As anthelmintic resistance grows, treating worm burdens becomes increasingly difficult, meaning more sheep suffer for longer. Strategic management to preserve drug efficacy is both a welfare and a long-term sustainability necessity.

What You Can Do

Support strategic parasite management training for sheep farmers
Advocate for worm egg count testing before treatment
Learn about FAMACHA and targeted selective treatment approaches