title: Efficacy of abamectin against nematodes in cattle.
abstract: Eight controlled trials were conducted, using 96 cattle of European breeds, to evaluate the efficacy of abamectin against natural and artificially acquired infections of adult and fourth-stage larvae of all the economically important gastrointestinal nematodes and lungworms in Germany and the United Kingdom. Half the animals were treated on one occasion with abamectin at a dose of 200 micrograms/kg bodyweight given subcutaneously while the other half remained untreated. Worms were counted 14 or 21 days after treatment or 28 days after the last infection. The treatment was highly effective (> 99 to 100 per cent) (P < 0.05) at removing immature (L4) stages and adult worms of the following species: Ostertagia ostertagi (inhibited larvae included), Trichostrongylus axei, Haemonchus contortus, Bunostomum phlebotomum, Cooperia species Oesophagostomum radiatum and Dictyocaulus viviparus. Naturally acquired adult C surnabada and Trichuris discolor infections were also significantly (P < 0.05) reduced. For Nematodirus helvetianus the efficacy varied from 89.8 to > 99 per cent (P > 0.1 to < 0.01). Abamectin gave full protection against the gastrointestinal nematodes O ostertagi, H contortus, Cooperia species and O radiatum for at least seven days and against the lungworm D viviparus for at least 14 days after treatment.
authors.affiliation: Merck, Sharp & Dohme Research Laboratories, Highfield Farm Goose Green, Hertford, Hertfordshire.
authors.forename: E M
authors.initials: EM
authors.lastname: Heinze-Mutz
authors.forename: S R
authors.initials: SR
authors.lastname: Pitt
authors.forename: K
authors.initials: K
authors.lastname: Bairden
authors.forename: D G
authors.initials: DG
authors.lastname: Baggott
authors.forename: J
authors.initials: J
authors.lastname: Armour
authors.forename: D
authors.initials: D
authors.lastname: Barth
authors.forename: L G
authors.initials: LG
authors.lastname: Cramer
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000627:therapeutic use*; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy* / Q000517:prevention & control; D004022:Dictyocaulus Infections / Q000188:drug therapy / Q000517:prevention & control; D005260:Female; D007411:Intestinal Diseases, Parasitic / Q000188:drug therapy / Q000517:prevention & control / Q000662:veterinary*; D007559:Ivermectin / Q000031:analogs & derivatives* / Q000627:therapeutic use; D008297:Male; D009349:Nematode Infections / Q000188:drug therapy / Q000517:prevention & control / Q000662:veterinary*
chemical_list: D000871:Anthelmintics; C048324:abamectin; D007559:Ivermectin