The efficacy of fenbendazole at a dosage rate of 5 mg/kg against Dictyocaulus viviparus.

Fenbendazole, dosed to artificially infested cattle at 5 mg/kg live mass, was more than 60% effective in more than 60% of the treated animals against 1-7 day-old Dictyocaulus viviparus larvae reducing the worm load by 87%. It was more than 80% effective in more than 80% of the treated animals against 8-21 day-old worms and 21-34 day-old worms and reduced the worm burdens by 99% in both cases.