Critical tests of suspension, paste, and pellet formulations of cambendazole in the horse

Three formulations of cambendazole were evaluated for anthelmintic activity by critical testing method in 21 horses. Cambendazole suspension was administered via stomach tube at the dose rate of 10 mg/kg to 3 horses and at the dose rate of 20 mg/kg to 3 horses. Cambendazole paste was given intraorally to 8 horses, and the pellet formulation was fed to 7 horses at the dose rate of 20 mg/kg. Anthelmintic activity of cambendazole was similar for all dose rates and formulations. Gasterophilus intestinalis, Gasterophilus nasalis, Draschia megastoma, Anoplocephala perfoliata, and Anoplocephala magna appeared to be refractory. The 3 formulations removed (1) 100% of Parascaris equorum and mature Oxyuris equi, (2) 82 to 100% of Strongylus vulgaris, (3) 80 to 100% of Strongylus edentatus, (4) 85 to 99% of small strongyles, and (5) 79 to 100% of immature Oxyuris equi. Probstmayria vivipara was present in only 1 horse and removal was 99%. There was some evidence of activity on Habronema muscae. Toxicosis was not observed.