Treatment of multiple resistant field strain of Ostertagia spp. in Cashmere and Angora goats.

A multiple resistant field strain of gastro-intestinal nematodes was detected in Cashmere and Angora goats imported from New Zealand. Different treatments with three types of broad spectrum anthelmintics (albendazole, levamisole/tetramisole and ivermectin) at various dose rates are described. Satisfactory effect in Angora goats was not achieved until all three anthelmintics were administered simultaneously at twice the normal sheep dose. Post mortem worm counts and identification revealed that the resistant population consisted of 89% Ostertagia circumcincta, 6% Ostertagia ostertagi and 5% Ostertagia trifurcata. However, egg hatch assay carried out seven months later detected the presence of resistant nematodes again.