It is not only a broad spectrum and the most efficacious pesticide of  Avermectin kind, but also one of the lowest distribution coefficient of this kind in milk. Trials show that the product with the concentration of 0.1mg/kg or 0.05mg/kg can efficaciously prevent seven kinds of nematodes parasitic on large intestine, small intestine and stomach of cattle and sheep, the efficacy is shown as at least 97%. When it is used to cow in milk, concentration ratio in milk to in plasma is not more than 0.2. It has the advantage over other drugs against nematodes parasitic on cow during milking.