EFFICACY OF A TOPICAL FORMULATION OF IVERMECTIN AGAINST NATURALLY ACQUIRED GASTROINTESTINAL NEMATODES IN WEANER CATTLE

The efftcacy of a topical formulation of ivermectin against naturally acquired gastro-intestinal nematodes in weaner cattle was evaluated. At slaughter, 14–15 days after treatment, burdens of Ostertagia spp, Trichostrongylus axei and Oesophagostomum radiatum were significantly lowler in the treated calves than in the untreated controls (p<0.01). Efficacies (based on geometric mean worm burdens of treated and control groups) were 99.6%, 95.1% and 100% respectively. The sizes of the Cooperia spp and Trichuris ovis burdens in the treated group did not differ significantly at the 5% level of confidence from those in the control group. © 1990 Taylor & Francis Group, LLC.