BENZIMIDAZOLE RESISTANCE OF EQUINE STRONGYLES - CRITICAL TESTS OF 6 COMPOUNDS AGAINST POPULATION-B

  • 1 January 1979
    • journal article
    • research article
    • Vol. 40  (4) , 590-594
Abstract
Critical tests were conducted on eight horses naturally infected with several species of large and small strongyles from population B. Tested were 6 benzimidazoles, including thiabendazole (2 lots) (44 mg/kg of body weight); mebendazole (8.8 mg/kg); cambendazole (2 formulations) (20 mg/kg); fenbendazole (10 mg/kg); oxibendazole (10 mg/kg); and oxfendazole (10 mg/kg). All compounds were administered by stomach tube except 1 of the 2 cambendazole formulations which was an intraoral paste. Removal of large strongyles (when present), Strongylus vulgaris and S. edentatus, was 100% by each drug. In general, 5 species of small strongyles (Cyathostomum catinatum, C. coronatum, Cylicocyclus nassatus, Cylicostephanus goldi and Cyl. longibursatus) exhibited varying degrees of resistance (percent removal) to all of the drugs except oxibendazole. A total of 19 other species of small strongyles from 7 genera, including the 3 described earlier were about 100% removed by the 6 benzimidazoles. Poor removal of immature (4th-stage larvae) forms was also characteristic of the 6 drugs.