Efficacy of injectable abamectin against gastrointestinal tract nematodes and lungworms of cattle.
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 micrograms 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.
Kaplan
R M
RM
Department of Infectious Diseases, University of Florida, Gainesville 32611.
Courtney
C H
CH
Kunkle
W E
WE
Zeng
Q Y
QY
Jernigan
A D
AD
Eagleson
J S
JS
D000818:Animals; D000871:Anthelmintics / Q000627:therapeutic use*; D002417:Cattle; D002418:Cattle Diseases; D005260:Female; D005767:Gastrointestinal Diseases / Q000188:drug therapy / Q000662:veterinary*; D007559:Ivermectin / Q000031:analogs & derivatives* / Q000627:therapeutic use; D008174:Lung Diseases, Parasitic / Q000188:drug therapy / Q000662:veterinary*; D009348:Nematoda / Q000302:isolation & purification; D009349:Nematode Infections / Q000188:drug therapy / Q000662:veterinary*; D010270:Parasite Egg Count
D000871:Anthelmintics; C048324:abamectin; D007559:Ivermectin