title: Anthelmintic efficacy of avermectin B1a and dihydroavermectin B1a against ovine gastrointestinal nematodes in 1977.
abstract: In a critical study, 40 female mixed-breed lambs with experimental infections of Cooperia spp, Trichostrongylus colubriformis, Ostertagia circumcincta, T axei, and Haemonchus contortus were allocated to 8 groups in 1977. Groups 1 and 5 served as controls. Groups 2 to 4 were treated orally with avermectin B1a at dosage levels of 25, 50, and 100 micrograms/kg of body weight, respectively. Groups 6 to 8 were given oral dihydroavermectin B1a at dosage levels of 50, 100, and 200 micrograms/kg, respectively. The lambs were euthanatized and necropsied 6 days after treatment. The compounds were greater than 99% effective at all dosage levels.
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000008:administration & dosage* / Q000627:therapeutic use; D004341:Drug Evaluation / Q000662:veterinary; D005260:Female; D005767:Gastrointestinal Diseases / Q000188:drug therapy / Q000662:veterinary; D006188:Haemonchiasis / Q000662:veterinary; D007411:Intestinal Diseases, Parasitic / Q000188:drug therapy / Q000662:veterinary*; D007559:Ivermectin / Q000031:analogs & derivatives; D007783:Lactones / Q000008:administration & dosage* / Q000627:therapeutic use; D010029:Ostertagiasis / Q000662:veterinary; D012756:Sheep; D012757:Sheep Diseases / Q000188:drug therapy*; D014252:Trichostrongyloidiasis / Q000188:drug therapy / Q000662:veterinary*; D014253:Trichostrongylosis / Q000662:veterinary
chemical_list: D000871:Anthelmintics; D007783:Lactones; C022120:avermectin B(1)a; D007559:Ivermectin