Breeding sheep for genetic resistance to internal parasites offers a sustainable, welfare-positive approach to reducing parasite burden without anthelmintic reliance.
Sheep with heavy parasite burdens experience anaemia, ill thrift, and in severe cases death. Anthelmintic resistance is a growing crisis threatening control options. Breeding programmes that select for parasite resistance provide sustainable welfare improvements that do not rely on drugs and reduce the welfare harm of repeated anthelmintic treatments.