EFFICACY OF PYRANTEL PAMOATE AGAINST SMALL STRONGYLE POPULATIONS

This study evaluated efficacy of pyrantel pamoate in horses with small strongyle (cyathostome) populations previously treated with each of t hree benzimidazole anthelmintics (fenbendazole, oxibendazole, and feba ntel). Thirty-six horses were randomly assigned to three treatment gro ups of 12 each. A rotational sequence was used where treatment with ea ch of the benzimidazole anthelmintics was followed 3 weeks later with pyrantel pamoate treatment. Fecal egg per gram (EPG) assays indicated that overall efficacy against cyathostomes was 44.3% for febantel, 61. 2% for fenbendazole, and 98.3% for oxibendazole. Pyrantel pamoate had 94.3% overall efficacy against cyathostome populations surviving treat ment with these benzimidazoles.