The efficacy of fenbendazole (methyl-5-(phenythio)-2-benzimidazole-carbamate) in cattle parasitized by the lungworm Dictyocaulus viviparus and in other cattle parasitized by Haemonchus, Ostertagia, Trichostrongylus, Cooperia, and Oesophagostomum was investigated in 3 controlled critical experiments. A single treatment with 5.0 mg/kg of body weight administered in the feed or in a 10% suspension exceeded 99% efficacy against these helminths. Dosages of 1, 0.5, 0.35, and 0.25 mg/kg of body weight administered for 5 days to individual calves in their feed were 99% efficacious against all helminths, except Haemonchus. The 1.0 mg/kg dose removed 99.5% of the Haemonchus, and the other 3 dosages had efficacies of 91.0, 93.7, and 95.6%, respectively. The small daily dosages were not evaluated against Dictyocaulus.

Animal Feed↗

PubMed1976

Controlled evaluation of fenbendazole as a bovine anthelmintic.

Calves experimentally infected with Haemonchus, Ostertagia, and Cooperia, and to lesser degrees with Trichostrongylus, Oesophagostomum, Nematodirus, and Bunostomum were used in a controlled experiment to record the anthelmintic efficacy of a benzimidazole compound methyl 5-(phenylthio)-2-benzimidazolecarbamate at dosage levels of 3.5, 5, and 7.5 mg/kg bodyweight. With the 3 dosages, reductions of Haemonchus were 96.7, 99.2, and 99.8%; of Ostertagia, 97.2, 97.2, and 99.5%; and of Cooperia, 99.9, 99.9, and 99.9%. Pronounced reductions were also recorded for Trichostrongylus, Nematodirus, Oesophagostomum, Trichuris, and Capillaria, but these populations were too numerically small or too unevenly distributed within the control groups to be given much emphasis. The experimental parasitic populations which developed in the 10 control calves amounted to 91, 763 worms (total).

Animals↗

PubMed1976

Efficacy of oxibendazole against adult and larval nematodes of cattle.

Calves which were artificially infected with Haemonchus, Ostertagia, Trichostrongylus, Cooperia, and Oesophagostomum but which were also carrying natural infections of Nematodirus and Trichuris were treated with 15.0 mg of oxibendazole (methyl-5-n-propoxy-2-benzimidazole-carbamate)/kg of body weight at 3 days, 7 days, and 42 days after exposure to the infective trichostrongylid and strongylid larvae. Efficacies against adult populations of these genera treated on day 42, except Trichostrongylus, exceeded 98%. The chemical was highly effective against immature nematodes of the genera, except Oesophagostomum (0%). Data were not obtained on Trichostrongylus. The oxibendazole premix was palatable, and toxicosis due to the chemical was not seen in these calves.

Animals↗