Efficacy of ivermectin administered via sustained-release bolus against gastrointestinal nematodes in cattle.

TitleEfficacy of ivermectin administered via sustained-release bolus against gastrointestinal nematodes in cattle.
Publication TypeJournal Article
Year of Publication1991
AuthorsZimmerman GL, Mulrooney DM, Wallace DH
JournalAmerican journal of veterinary research
Volume52
Issue1
Pagination62-3
Date Published1991 Jan
ISSN0002-9645
KeywordsAnimals, Cattle, Cattle Diseases, Delayed-Action Preparations, Ivermectin, Larva, Nematoda, Nematode Infections, Ostertagia, Trichostrongylus
Abstract

Twelve calves (mean weight, 175.5 kg) were used to confirm efficacy of ivermectin delivered from a prototype sustained-release bolus against naturally acquired gastrointestinal nematodes including early fourth-stage (inhibited) larvae of Ostertagia ostertagi. The calves were allocated by restricted randomization on weight to 1 of 2 groups: controls, to which a placebo bolus was given orally, and treated calves, to which a sustained-release bolus designed to deliver 8 mg of ivermectin/day at a steady rate was given orally. After treatment, the 2 groups were housed in separate pens with concrete flooring. Twenty-eight days after treatment, all calves were euthanatized and necropsied. The ivermectin-treated calves had no larval or adult Ostertagia spp and significantly (P less than 0.01) fewer adult Trichostrongylus axei and adult Cooperia (C oncophora, C punctata and C surnabada) than control calves. Efficacy of ivermectin was greater than 99% for Cooperia spp, and 100% for other parasites. Drug-related adverse reactions were not observed.

Alternate JournalAm. J. Vet. Res.