Duration of the persistent activity of moxidectin against Haemonchus contortus in sheep.
Weaned lambs were infected with Haemonchus contortus 35, 28, 21, 14 and 7 days after treatment with moxidectin at 0.2 mg/kg and 35 and 14 days after treatment with ivermectin at the same dose rate. Worm counts 14 days after infection showed that moxidectin prevented the establishment of over 99% of infective larvae for 28 days and reduced the establishment rate at 35 days by 96%, relative to ivermectin. There was no difference in the protective efficacy of ivermectin at 14 or 35 days. The persistence of moxidectin is likely to provide advantages in nematode control, particularly when used as a strategic early summer treatment or as a pre-lambing treatment to ewes. Implications of the persistent activity of moxidectin for the development of resistance during the decay phase are discussed.
Abbott
K A
KA
Department of Animal Health, University of Sydney, Camden, New South Wales.
Cobb
R M
RM
Glass
M H
MH
D000818:Animals; D000871:Anthelmintics / Q000627:therapeutic use*; D000900:Anti-Bacterial Agents; D000977:Antiparasitic Agents / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D005260:Female; D006188:Haemonchiasis / Q000188:drug therapy / Q000662:veterinary*; D007559:Ivermectin / Q000627:therapeutic use; D018942:Macrolides / Q000627:therapeutic use; D008297:Male; D012756:Sheep; D012757:Sheep Diseases / Q000188:drug therapy*; D013997:Time Factors
D000871:Anthelmintics; D000900:Anti-Bacterial Agents; D000977:Antiparasitic Agents; D018942:Macrolides; D007559:Ivermectin; C027837:moxidectin