Efficacy of ivermectin against the abomasal nematode mecistocirrus digitatus in naturally infected zebu calves.

Anthelmintic efficacy of ivermectin against Mecistocirrus digitatus was evaluated in 10 naturally infected zebu calves. Group 1 (n = 5) was not treated, and group 2 (n = 5) was treated SC with 200 micrograms of ivermectin/kg of body weight. Calves were euthanatized 14 or 15 days after treatment. There was 100% overall reduction of M digitatus in treated calves, which was significant (P = 0.0079) compared with reduction in controls. Cooperia punctata, Haemonchus similis, and Trichostrongylus axei were found in controls. Efficacy against these parasites in treated calves was 100%.