Research note: use of fenbendazole for the treatment of turkeys with experimentally induced nematode infections.

Turkeys were raised under parasite-free conditions until 25 days of age at which time the birds were administered infective ova of Capillaria obsignata, Heterakis gallinarum, and Ascaridia dissimilis. At 28 days postinfection, four groups of birds were placed on rations medicated with fenbendazole at 15,30,45, or 60 ppm. These rations were given ad libitum for 6 consecutive days. At 31 days postinfection, five additional groups of birds were placed on rations medicated with fenbendazole at 15,30,45,60 or 120 ppm. These latter rations were given ad libitum for 3 consecutive days. One group of turkeys served as an unmedicated, infected control. Treatment group size ranged from 17 to 19 birds. All birds were necropsied 5 days after the medicated rations were withdrawn and nematode recovery was performed. Control birds harbored an average of 3.29 A. dissimilis, 12.06 H. gallinarum, and 65.94 C. obsignata. All but one of the fenbendazole-medicated groups showed 100% removal of A. dissimilis. The exception was that group that received fenbendazole at 15 ppm for 6 days, and that showed a 98.5% efficacy. The removal rate for H. gallinarum ranged from 78.6% (15 ppm for 3 days) to 100% (120 ppm for 3 days and 45 ppm for 6 days). The C. obsignata infections proved dose-limiting, with a removal rate ranging from 30.8% (15 ppm for 3 days) to 97.8% (45 ppm for 6 days).