a field survey on resistance to albendazole in gasterointestinal nematodes of sheep in khozestan province of iran

in this survey, resistance to albendazole was investigated in 15 sheep flocks from different regions of khozestan province. on each flock, two groups of 15 sheep including control groups (untreated) and albendazole group (treated with 5 mg/kg of albendazole) were selected and the investigation was carried out using faecal egg count reduction test(f.e.c.r.t) for 10 days after treatment.posttreatment faecal culture and necropsy of 4 sheep from control group and 6 sheep from albendazole group were done to identify species of resistant nematodes. results of f.e.c.r.t showed that 27% of the flocks were resistant,53% were suspected to resistancy and the rest were susceptable to albendazole. faecal culture of necropsied animals showed that resistantce to albendazole was developed in ostertagia circumcincta and marshalagia marshali.