Effect of toltrazuril at single dose against Eimeria spp. in lambs kept at pasture in condition favorable to coccidiosis

The aim of this study was to evaluate the efficacy and the cost-benefit ratio of the treatment with a single-dose of toltrazuril 5% to control Eimeria spp. infection in lambs kept at pasture in condition favorable to coccidiosis. This experiment was designed after a lamb of the target-flock died due to acute diarrhea caused by clinical coccidiosis. Thirty-two lambs of both genders and age approximately 6-7 months were randomized between two groups, balanced by oocysts per gram of feces (OPG) count and live weight. The group TOL was treated with toltrazuril 5% in a single dose and group CON was the untreated (control). Individual feces were collected weekly from day 0 until day 84 after the onset of the treatment. Lambs were weighed at days 0, 84, and 126; and the costs of the treatment were calculated. Efficacy of the treatment using toltrazuril 5% was higher than 95 % until day 21. Treated lambs become re-infected on day 28. E. ahsata was the most frequent species found in the lambs feces. There was no significant diff;erence in weight gain between the groups. The total cost of the treatment was U$2.32 per animal, and the economic loss caused by death of lamb was U$38.4. Thus, although the treatment with a single-dose of toltrazuril has been effective against Eimeria spp. infection, it was not considered economically feasible in lambs with subclinical coccidiosis. However, the treatment with toltrazuril can become a cost-effective option to prevent clinical coccidiosis and deaths of lambs caused by Eimeria spp. infection at pasture system.