Resistance to ivermectin in a field strain ofOstertugiaspp. in goats

Abstract
The occurrence of a field strain of Ostertugia spp. showing a resistance to ivermectin in Angora goats is reported. In a controlled anthelmintic trial using naturallv-infected goats. ivermectin at a dose rate of 0.2 mg/ kg demonstrated an efficacy of 87% against this strain. (New Zealand Veterinary Journal 38,72–74, 1990)