Slowing the spread of anthelmintic resistant nematodes of sheep and goats in the United Kingdom

Department of Parasitology, Central Veterinary Laboratory, New Haw, Weybridge, Surrey.

Anthelmintic resistant nematodes pose an increasing threat to animal welfare and lamb production on lowland sheep farms in the United Kingdom. Based on published information on anthelmintic resistance in nematodes and insecticide resistance in arthropods, seven recommendations are made for reducing the development and spread of anthelmintic resistant nematodes. The two most important are probably to prevent the introduction of resistant worms through the purchase of stock and to reduce the reliance on frequent anthelmintic treatments by using epidemiological principles of nematode control.