title: Therapeutic and protective efficacy of doramectin injectable against gastrointestinal nematodes in cattle in New Zealand: a comparison with moxidectin and ivermectin pour-on formulations.
abstract: Two similar studies were conducted in New Zealand to compare the therapeutic and persistent activity of doramectin injectable, moxidectin pour-on, ivermectin pour-on and oxfendazole oral drench when administered to nematode-infected cattle which were then grazed on common pastures. On day 0 (treatment day), 40 cattle were weighed, faecal sampled and allocated on the basis of day--3 faecal egg counts (FEC) to four treatment groups. Cattle were then treated with either doramectin by subcutaneous (s.c.) injection, moxidectin and ivermectin by topical application, or oxfendazole orally using label-recommended dosages. Oxfendazole treatment served primarily as a control to monitor reinfection without persistent activity. Faecal samples for nematode egg counts and coprocultures for larval differentiation were collected six times between day 0 and day 56 and all cattle were reweighed on day 56. Doramectin reduced pretreatment FEC by 99.1% in the first study and by 100% in the second study when assessed at 14 days posttreatment. Corresponding reductions for moxidectin were 80.8% and 85.2%, for ivermectin 86.0% and 80% and oxfendazole 78.3% and 100%, respectively. Posttreatment rise in FEC indicated that reinfection of moxidectin-treated animals occurred at the same time as oxfendazole controls in both trials. Posttreatment rise in FEC with ivermectin pour-on was similar to moxidectin and oxfendazole in one study, but in the other study ivermectin pour-on delayed the rise by 14-21 days. The rise in FEC for doramectin was delayed for 14-21 days in one study and at least 21 days in the other. The better parasite control provided by doramectin resulted in greater weight gains for cattle over the 56-day period as compared to moxidectin pour-on, ivermectin pour-on and oxfendazole in both trials. Gains of doramectin treated cattle were significantly (p < 0.05) greater than those of ivermectin and moxidectin groups in one trial and the oxfendazole group only in the other.
authors.affiliation: Pfizer, Sydney, Australia.
authors.forename: F G
authors.initials: FG
authors.lastname: Hooke
authors.forename: P
authors.initials: P
authors.lastname: Clement
authors.forename: D
authors.initials: D
authors.lastname: Dell'Osa
authors.forename: R M
authors.initials: RM
authors.lastname: Porter
authors.forename: D
authors.initials: D
authors.lastname: MacColl
authors.forename: R S
authors.initials: RS
authors.lastname: Rew
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000871:Anthelmintics / Q000008:administration & dosage / Q000627:therapeutic use*; D000900:Anti-Bacterial Agents; D002417:Cattle; D002418:Cattle Diseases; D005243:Feces / Q000469:parasitology; D005260:Female; D005767:Gastrointestinal Diseases / Q000469:parasitology / Q000517:prevention & control / Q000662:veterinary*; D007279:Injections, Subcutaneous; D007559:Ivermectin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D018942:Macrolides / Q000008:administration & dosage / Q000627:therapeutic use; D008297:Male; D009349:Nematode Infections / Q000517:prevention & control / Q000662:veterinary*; D009520:New Zealand; D010270:Parasite Egg Count; D012008:Recurrence; D015430:Weight Gain
chemical_list: D000871:Anthelmintics; D000900:Anti-Bacterial Agents; D018942:Macrolides; D007559:Ivermectin; C084101:doramectin; C027837:moxidectin