Epidemiological Investigation And Study On Sheep Helminthiasis And The Anthelmintic Effects In Wushen

Wushen area is a traditional county for animal husbandry,and also is the main sheep production base of Inner Mongolia Autonomous region.However,the helminthiasis,mostly gastrointestinal nematode disease of sheep in this area prevailed commonly,which seriously affects the production performance of sheep and hinder the healthy development of local sheep industry.Moreover,the local farmers do not know enough about the harm of helminthiasis,the process of prevention and treatment of worm disease is lack of scientific and pertinence,the phenomenon of blind drug administration is very common,and the prophylaxis and treatment of helminthiasis is obviously lagging behind.To investigate the main helminth infections in sheep in Wushen area and to study the effect of commonly used antihelmintic drugs,the following studies were performed from March in 2017 to March in 2018.The epidemiological investigations of sheep helminthiasis were carried out four different periods based on the different pasture types and grazing patterns of natural grazing sheep in Wuhen county by using qualitative and quantitative fecal egg examination method and dissecting method.In order to know the resistance of dominant nematode species to commonly used antinematodal drugs in this area and to screen out the best effective drugs,a typical sheep herd was selected in each experimental area to carry out the deworming test and tracking investigation.The results showed that the average total helminth infection rate of sheep in the four investigated areas was 84.4%,66.6%,51% and 31.9%,respectively.The helminth infection was most severe at the time of the first investigation,especially the infection of the gastrointestinal nematodes was the most common with 84.3%.11 species of parasitic helminth were identified based on morphological identification of fecal eggs and morphology of adult helminth.They are belonging to 2 phyla,4 classes,4 orders,7 families and 11 genera,and including 7 species of nematode,2 species of cestode and 2 species of trematode.Specific categories include Hemonchus contortus,Nematodirus sp,Chabertia sp,Ostertagia circumcincta,Trichocephala ovis,Trichostrongylus sp,Oesophagostomum spp,Helictrometa giardia,Moniezia sp,Paramphistomes and Fasciola hepatica.Dominantly infected species were Hemonchus contortus and Nematodirus sp,the infection rates in the first survey were 84.3% and 65.6%,respectively.Moreover,these dominant species have high resistance to Avermectins and Albendazole,which are widely used currently,the fecal egg reduction rate is less than 10%,and the negative rate is 0.The dominantly infected species are strong resistance to Levamisole,the egg reduction rate was about 60% and the egg negative rate was about 30%.However,Disophenol Injection and Nitroxynil injection,which rarely used in this area,possess strong antihelmintic effect on gastrointestinal nematodes,especially on the hemonchus contortus parasitic in abomasum.Therefore,first of all,the epidemic situation of sheep helminthiasis in Wushen county was very common and serious,especially the infection of hemonchus contortus and Nematodirus sp.Secondly,the dominantly infected nematodes of sheep in Wushen area and their drug resistance were revealed.Thirdly,drugs with powerful antihelmintic effects on the dominant species prevailing in Wushen area were screened out by the anthelmintic examinations and follow-up investigation,and the reasonable antihelmintic scheme which is suitable for the local area was developed successfully.