A comparison of topical, subcutaneous and oral administrations of ivermectin to reindeer.

The topical administration of ivermectin to adult reindeer hinds was evaluated by comparing its antiparasitic efficacy at a dose of 500 micrograms/kg bodyweight with that of oral administration at a dose of 200 micrograms/kg and subcutaneous administration at dosages of 20 and 200 micrograms/kg. The comparison included faecal examinations for nematode eggs and larvae and the counting of warbles and throat bots (Oedemagena tarandi and Cephenomyia trompe larvae). Weight changes and calf birth weights were recorded. All the treatments were 100 per cent effective against warbles and all except the low subcutaneous dose (20 micrograms/kg) against throat bots. The anti-nematodal efficacy of the topically applied ivermectin, the orally administered drug and the low subcutaneous dose was inferior to that of the subcutaneous dose of 200 micrograms/kg. There were no differences in weight changes between the groups.