Parasite resistance trends and practical implementation of fecal egg counts

Abstract

Anthelmintic resistance in the United States has recently gained the attention of the veterinary and livestock communities. The rapid rise in resistance to 2 new drug classes shortly after approval outside the United States calls for new strategies and recommendations for maintaining an effective anthelmintic program even as new drugs become available. The development of resistance is product-dependent, with observable differences between classes. Methods used to test anthelmintic efficacy allow the veterinary practitioner to make informed treatment decisions; however, the results should be interpreted carefully due to the limitations for the fecal egg count procedure.