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.