Equine

ANS 490A: Summary of Current Guidelines for Management of Internal Parasites in Horses

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Abstract

Parasite control has traditionally involved regular rotation of dewormers to treat large strongyles (bloodworms), which were the main equine internal parasite of concern in the past. The treatment was effective, and today, large strongyles are a rare occurrence in horses. Many horses no longer require frequent treatment for parasite control. Today, the most significant parasite infection in adult horses has changed from large strongyles to small strongyles. The roundworm, or ascarid, continues to be the primary concern in foals and yearlings. New recommendations are available for improved management of parasites in horses. These recommendations aim to treat and maintain parasitic infection at a threshold where it does not cause physical illness to the animal. With the past practice of regular rotation, parasites began to develop resistance to all the available types of dewormers. Today, there is evidence which indicates that dewormers are losing effectiveness in treating internal parasite infections. The aim of current recommendations is to reduce the spread of resistance, avoid physical illness in horses,  and to limit parasite egg shedding in horse populations. Implementing a parasite management plan requires a general understanding of parasites, dewormers, and resistance. This paper aims to explain these terms for horse owners so they can build an effective management plan in treating parasites in horses while mitigating resistance to dewormers.

How to Cite:

Carlo, A., Ferwerda, N. S. & Howard, J., (2024) “ANS 490A: Summary of Current Guidelines for Management of Internal Parasites in Horses”, Iowa State University Animal Industry Report 21(1). doi: https://doi.org/10.31274/air.18336