Efficacy of fenbendazole against naturally acquired Raillietina cesticillus infections of chickens.

Birds were obtained from a commercial broiler operation where birds were naturally infected with Raillietina cesticillus at an incidence of 40%. Fenbendazole was added to the diet for six consecutive days at 30, 60, 120 or 180 mg/kg or at 60 or 120 mg/kg for 3 days. Birds were necropsied over a 3-day period beginning 4 days after fenbendazole withdrawal. Anthelmintic efficacies for the 6-day regimens of fenbendazole at the dietary rates of 30, 60, 120 and 180 mg/kg were 76, 73, 77 and 95%, respectively. In regard to the 3-day regimens of fenbendazole, efficacies were 48 and 51% for the 60 and 120 mg/kg diets, respectively. Fenbendazole did not affect the palatability of the diet nor induced any adverse effects.