Detection of anthelmintic resistance in naturally occurring gastrointestinal nematodes in unorganized sheep farms

Anthelmintic resistance against commonly used anthelmintics (ivermectin, levamisole, morantel and fenbendazole) was studied in naturally occurring gastrointestinal (GI) nematodes in adult sheep of unorganized sheep farms of district Ludhiana (Punjab). After qualitative and quantitative screening of faeces of 100 sheep, fifty sheep having eggs per gram of faeces (EPG) >500 were randomly selected and divided into five equal groups. Ivermectin @ 200 μg/kg body weight and levamisole @ 7.5 mg/kg body weight, injected subcutaneously, in two different groups, were 99.08 and 98.17 per cent effective, respectively. Whereas, fenbendazole @ 7.5 mg/kg body weight and morantel citrate @ 6.0 mg/kg body weight, orally was 66.28 and 95.41 per cent effective and the fifth group was kept as untreated control with natural exposure to gastrointestinal nematodes. Hence, it was concluded that the naturally occurring GI nematodes of sheep were susceptible for ivermectin and levamisole, suspected for resistance against morantel citrate and were resistant to fenbendazole.