title: Evaluation of the persistence of the effect of ivermectin and abamectin against gastrointestinal and pulmonary nematodes in cattle.
abstract: The persistence of the effect of ivermectin and abamectin against gastrointestinal nematodes and lungworm in cattle was evaluated in two trials, each involving 28 animals. Groups of seven cattle either remained untreated, or were treated topically with ivermectin at 500 micrograms/kg bodyweight or subcutaneously with either ivermectin or abamectin at 200 micrograms/kg bodyweight. Starting on the day of treatment the cattle were given daily trickle infections with various infective nematode larvae for two weeks (Haemonchus species, Trichostrongylus axei and Cooperia species), three weeks (Ostertagia ostertagi and Oesophagostomum radiatum) and four weeks (Dictyocaulus viviparus). The cattle were killed 49 to 51 days after treatment and their worm burdens measured. An efficacy of > 99 per cent was recorded in all the groups demonstrating that the products controlled Haemonchus species, T axei, C oncophora, C punctata and C surnabada for at least two weeks, O ostertagi and O radiatum for at least three weeks and D viviparus for at least four weeks.
authors.affiliation: Merck Research Laboratories, Rohrdorf, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Barth
authors.forename: G F
authors.initials: GF
authors.lastname: Ericsson
authors.forename: B N
authors.initials: BN
authors.lastname: Kunkle
authors.forename: S
authors.initials: S
authors.lastname: Rehbein
authors.forename: W G
authors.initials: WG
authors.lastname: Ryan
authors.forename: D H
authors.initials: DH
authors.lastname: Wallace
mesh_terms: D000287:Administration, Topical; D000818:Animals; D000871:Anthelmintics / Q000627:therapeutic use*; D000969:Antinematodal Agents / Q000627:therapeutic use*; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy* / Q000469:parasitology; D005767:Gastrointestinal Diseases / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary*; D007275:Injections, Intravenous; D007559:Ivermectin / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D008171:Lung Diseases / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary*; D009349:Nematode Infections / Q000188:drug therapy / Q000662:veterinary*
chemical_list: D000871:Anthelmintics; D000969:Antinematodal Agents; C048324:abamectin; D007559:Ivermectin