Use of moxidectin treatment in the investigation of abomasal nematodiasis in wild reindeer (Rangifer tarandus platyrhynchus).

An experiment was conducted to evaluate moxidectin as a tool for understanding the impact of parasitism on wild Svalbard reindeer (Rangifer tarandus platyrhynchus). Adult females were injected subcutaneously with moxidectin at a dose rate of 0-4 mg/kg bodyweight, and groups of animals were culled within its expected period of efficacy (around 14 days) or around 12 or 24 weeks after treatment. Moxidectin was effective in eliminating the reindeers' abomasal worm burdens, and although they became reinfected, worm burdens were significantly lower in the treated animals compared to the untreated controls for up to 24 weeks after treatment. Nematode eggs did not reappear in faeces until five weeks after treatment, a similar period to that claimed by the manufacturer for sheep and cattle. Animals culled 12 and 24 weeks after treatment had been reinfected and harboured a wide range of abomasal worm burdens which contributed to the understanding of the seasonal variation in the relationship between faecal egg count and worm burden.