Published November, 2014

A recent survey conducted by researchers at the University of Kentucky (UK) found a high percentage of Thoroughbred farm managers used rotational deworming without monitoring drug effectiveness.

Martin Nielsen, DVM, PhD, Dipl. EVPC, ACVM, assistant professor at the UK Gluck Equine Research Center, and Jill Stowe, PhD, director of UK Ag Equine Programs and associate professor in agricultural economics, teamed up for the study.

They sent a survey to registered Thoroughbred farm managers in Kentucky to investigate their current approaches for parasite control, awareness of drug-resistant parasites, and possible willingness to change their current approaches. The study's goal was to understand how experienced farm managers approached parasite control.

The survey showed nearly 70% practiced rotational deworming without monitoring drug efficacy, even though 80% of those surveyed indicated they take veterinarian advice into consideration for constructing their deworming strategies. The survey also found respondents dewormed horses five to seven times per year, depending on the horses' ages.

“Chances of finding an equine operation without drug-resistant parasites have become very slim in recent years,” Nielsen said. “But the study suggests that although managers may be motivated to develop more sustainable deworming strategies, very few have actually done so.”

Farm managers rarely monitor parasite egg shedding and evaluate treatment efficacy, and treatment intensities are substantially higher than recommended. The study results indicate a need for better dissemination of parasite control recommendations to farm managers and veterinarians.

“As scientists and experts we clearly have not communicated our recommendations effectively to the end users,” Nielsen said.

Respondents appeared willing to invest time and/or money in revised or new parasite control programs only if they could be assured success of avoiding resistance and parasitic diseases. Farms closer to the Lexington area were also more likely to consider paying a premium for surveillance-based parasite control strategies. Respondents who have started using fecal egg counts in their deworming strategies were also more likely to pay a premium.

“This study shows that in addition to effectiveness of treatment strategies, farm managers also factor efficiency and time costs into their decision-making,” Stowe said. “They are willing to adopt more expensive and time-intensive strategies only if those strategies are guaranteed to work exceptionally well.”

Nielsen added it is important for farm managers to be aware they might be using drugs that no longer work due to drug resistance.

The paper titled “Attitudes towards implementation of surveillance-based parasite control on Kentucky Thoroughbred farms – current strategies, awareness, and willingness-to-pay” was published in Equine Veterinary Journal.

For more information on parasite control guidelines, see the American Association for Equine Practitioners (AAEP) publication. Nielsen chaired the task force for the publication.

Jenny Evans, MFA, is the interim executive director of the UK Gluck Equine Research Foundation and marketing and promotion specialist senior at the UK Gluck Equine Research Center.