Problem statement: There are several anthelmintic classes based on chemical structure that are in use, but, during the last 20 years, it has been increasingly noted that the target parasites have become resistant, the incidence varying with geographical location and mode of use. Approach: In this study, 60 apparently healthy cow under the same management conditions of the experiment, feces (EPG) were examined. Cows devided to 2 groups (30 = control, 30 = treated with closantel 5%) then treated cows received 10 mg kg-1 B.W closantel 5% oraly and After treatment the cow, faecal samples from each of 2 groups were examined in days 1-7-21-28 after treatment by wet-mount and willis-methods and MC-master slid used for egg counte. Results: Therefore Closantel 5% drugs if used oraly by dosage 1 mL 10 kg-1 B.W in cow against Fasciola hepatica and Haemonchus spp. Bunostomum phlebotomum been quite effective (average percentage of drug effect = 97%) and used for control and prevention of parasitic infections in cow is recommended. Conclusion: Therefore Closantel 5% is a effective drug against cattle gastrointestinal helminthes in Iran.
