Efficacy of abamectin against gastrointestinal tract nematodes and lungworms of cattle was determined in 4 experiments. The first 2 experiments were controlled trials in which efficacy was determined at necropsy in calves with either experimentally induced (n = 14) or naturally acquired (n = 16) infections. Half the calves in each experiment were treated with abamectin (200 micrograms/kg of body weight, sc), and half were left untreated as controls. Efficacy was > 99% against adult stages of Dictyocaulus viviparus, Haemonchus placei, Ostertagia ostertagi, Trichostrongylus axei, Cooperia punctata, Trichuris discolor, and C oncophora, and was 92.4% against Nematodirus helvetianus. The second 2 experiments were clinical trials in which efficacy was determined by fecal egg count reduction in naturally infected yearling heifers (n = 75) or 2-year-old heifers (n = 75). Within replicates of 5, 4 heifers were assigned at random to treatment with 200 Kg of abamectin/kg and 1 was left untreated as a control. Abamectin was 100% effective in eliminating strongylate nematode eggs from the feces of these heifers. In all experiments, adverse reactions were limited to small, clinically unimportant injection site swellings in 29% of abamectin-treated calves. Abamectin was judged to be safe and effective in these trials.

gastrointestinal nematodes in calves (exper.) causing severe anemia, effect on preparation of carrier erythrocyte ghosts and erythrocyte survival

gastrointestinal nematodes, calves (exper.), efficacy of ivermectin given subcutaneously or given orally as drench or paste

nematodes, calves, albendazole evaluated

Ostertagia ostertagi, beef cattle, acquisition of inhibited larvae during winter and spring, efficacy of ivermectin against inhibited early 4th-stage larvae of O. ostertagi and other nematodes of abomasum and intestinal tract: Louisiana

nematodes of ruminants, large scale technique for recovery of worms migrating from gastro-intestinal ingesta gelled in agar, significantly more male than female worms failed to migrate, L4 stages generally migrated more efficiently than did adult worms, some genera migrated more efficiently than others, applications for use in quantitative worm recovery such as in anthelmintic testing

Bunostomum phlebotomum experimental infection of beef calves superimposed upon naturally occurring gastrointestinal nematode infections, fenbendazole anthelmintic efficacy tested

gastrointestinal helminths in calves, field conditions, febantel, no activity against Moniezia benedeni, no signs of intoxication