A survey to evaluate anthelmintic resistance of gastrointestinal stongyles in Iowa cow/calf operations

Abstract

Parasite resistance, a widespread problem in small ruminants, is starting to appear with increased frequency in beef cattle populations. Reports of parasite resistance in cattle have surfaced in Australia, New Zealand, northern Europe, South America, and the United States. The objectives of this study were to determine whether parasite resistance to commonly used anthelmintics is present in Iowa cow/calf operations, attempt to identify factors that contribute to development of parasite resistance, and utilize qualitative PCR testing to determine which genera of parasites are associated with resistance.