Deworming Effect of Doramictin and Ivermectin in Small dose on Cattle Grub in Yak

The deworming effect was studied by using deramectin injection and ivermectin pour-on solution in a small dose in yak calves which were naturally infected by cattle grub.The results of autopsy in the period of 28～34 days after administration and palpation of the back of yak in March and May of next year showed that the deworming clean rate and the deworming rate in the yaks of doramectin group in a dose of 5μg/kg were 85.0% and 92.1%,93.6% and 93.7%,respectively,and in adose of 10μg/kg and 20μg/kg were all 100.0%.The deworming clean rate and the deworming rate in the yaks of ivermectin group in a dose of 12.5μg/kg were 85.0% and 91.2%,93.3% and 93.2%,respectively,and in a dose of 25μg/kg and 50μg/kg were all 100.0%.The infectious rate of first-instar grub in the yaks of control group was 85.0% and the average infectious intensity was 29.7.The average infectious rate of subcutaneous warbles and the number of skin hole of parasites were 84.1% and the total number of warbles and parasite holes was 205.This experiment results proved that both doramectin and ivermectin in a small dose were effective,safe and economic for deworming the first-instar grub.The op timum dose of doramectin was 10μg/kg and of ivermectin was 25μg/kg.