Milk kinetics of moxidectin and doramectin in goats

The milk kinetics of doramectin after a single subcutaneous administration and moxidectin following a single subcutaneous or oral drench were studied in goats (n = 15) at a dosage of 0.2 mg kg(-1). Doramectin could be detecte d in the milk for 21.0 +/- 2.9 days after subcutaneous treatment, and the t otal fraction of the dose recovered from the milk was estimated to be 2.9 /- 0.88 per cent. Moxidectin. after either oral or subcutaneous administrat ion, could be detected in the milk up to day 40 and the total fractions of the dose recovered from the milk were estimated to be 5.7 +/- 1.04 per cent and 22.53 +/- 1.09 per cent, respectively. The mean residence time after s ubcutaneous administration indicated that moxidectin delivered by the milk persists three times longer than doramectin; furthermore, the total fractio n of the dose of moxidectin recovered from the milk was 7.7 times higher th an that of doramectin. (C) 2001 Harcourt Publishers Ltd.