COMPARATIVE EFFICACY OF 3 GROUPS OF ANTHELMINTICS AGAINST SHEEP NEMATODES RESISTANT TO BENZIMIDAZOLES

Resistance to several anthelmintic types (benzimidazoles, avermectines, nitrophenylguanides) of three nematode strains isolated from sheep flocks was estimated by an in vivo test. The resistance of the three species (Teladorsagia circumcincta, Haemonchus contortus, Trichostrongylus colubriformis) to benzimidazole compounds confirmed the in vitro tests done previously. Differences were nevertheless observed according to the molecule and to the species. With regard to other anthelmintic types, netobimin was fully effective (100 p. cent) and the efficacy of ivermectine was 99.98 p. cent. In addition, the results showed that the relevance of coproscopical tests depends on the date of sampling.