| Abstract: | Ivermectin was evaluated for anthelmintic activity in calves naturally infected with gastrointestinal helminths. Five of 10 calves were treated subcutaneously with ivermectin at 200 micrograms per kg body weight. One-hundred percent efficacy was indicated against adult and immature Haemonchus, Trichostrongylus, Bunostomum phlebotomum and Oesophagostomum radiatum. Adult Cooperia were also completely eliminated, and a 95.5% reduction was obtained for the immature forms; an 88.7% reduction was obtained for Trichuris spp. |
