Comparative Trials

Pasture Coccidiosis

A blinded, positive and negative controlled clinical field study was done to evaluate the efficacy of Baycox® 5% (toltrazuril) and diclazuril in the treatment of clinical signs of coccidiosis in calves kept on pasture. For this study, three German farms with a history of recurrent outbreaks of coccidiosis in animals on pasture were selected. None of the selected animals received any anticoccidial treatment four weeks before turnout. On the day of release to pasture, 60 animals (4 to 10months of age) of either sex were randomized and allocated to three study groups. One group of animals was treated with Baycox® 5%(toltrazuril 15 mg/kg), the second group with diclazuril 1 mg/kg and the third group served as negative control. Samples of faeces from each animal in the trial were collected on the day before treatment and every two to three days until the end of the study. The samples were examined for Eimeria alabamensis and Eimeria bovis using a modified McMaster method. The clinical signs of diarrhoea were evaluated over a period of 21 days. Only two calves treated with Baycox® showed clinical signs of diarrhoea one day after treatment (day 6 or 11 after treatment), whilst diarrhoea was observed in calves treated with diclazuril and in untreated calves at same frequency and for a similar length of time. The average number of oocysts of Eimeria alabamensis found in calves treated with Baycox® 5% was at a low level (maximum 84) throughout the study. The average number of oocysts of Eimeria alabamensis determined in calves treated with diclazuril or left untreated peaked 9 days post- application (approximately 10,000 oocysts per gram faeces). Only few Eimeria bovis were observed in all groups. During the 21 days of the trial the groups treated with Baycox® 5% gained more weight than the other groups (Epe et al., 2006).