Investigation On Resistance To Routine Anthelmintics In Gastrointestinal Nematodes From Grazing Sheep

In recent years,the resistance to routine anthelmintics in gastrointestinal nematodes from grazing sheep has been increasing and brings great harmness to the animal husbandry,which has attracted the attention of researchers in the world.In order to know the drug resistance of gastrointestinal nematode in grazing sheep,several tests were carried out and the results were as follows:Firstly,the high performance liquid chromatography and the ultraviolet spectroscopy was used to evaluate the effective component of the anthelmintics and their quality.The result showed that the qualification rate of the 21 kinds of routine anthelmintics from markets was only 23.8%.Among them,only 13 preparations of Ivermectin could meet the regulations and their qualification rate was 23.1%;For Albendazole,20%was qualified,and only 20%of the five Closantel sodium drugs could meet the requirment.In a word,the anthelmintics of routine had a low pass rate and the quality problem was serious.Secondly,three kinds of the drugs(Ivermectin,Albendazole and Closantel sodiumin),whose quality could meet the state regulations were selected and the fecal worm egg reduction experiment was used to investigate the three drugs' resistance of gastrointestinal nematodes in grazing sheep in Hulunbeier,Helin and Salaqi areas.The result indicated that the gastrointestinal nematodes in grazing sheep had developed the resistance to Ivermectin and Albendazole to some extence,but they were sensitive to Closantel sodium in these three regions.Finally,further investigation of the resistance to Ivermectin and Albendazole was carried out by larval development inhibition experiment and egg hatching assay in Haemonchus confortus of some sheep around Hohhot.The study showed that the resistance to Ivermectin and Albendazole was also existed.