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 detected in the milk for 21.0+/-2.9 days after subcutaneous treatment, and the total fraction of the dose recovered from the milk was estimated to be 2.9+/-0.88 per cent. Moxidectin, after either oral or subcutaneous administration, 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 subcutaneous administration indicated that moxidectin delivered by the milk persists three times longer than doramectin; furthermore, the total fraction of the dose of moxidectin recovered from the milk was 7.7 times higher than that of doramectin.