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Using diagnostics in supporting sustainable worm control in horses

02 November 2023
12 mins read
Volume 7 · Issue 6
Figure 1. Key components of sustainable equine helminth control programmes. *Note: this practice is not suitable or effective to reduce F. hepatica.
Figure 1. Key components of sustainable equine helminth control programmes. *Note: this practice is not suitable or effective to reduce F. hepatica.

Abstract

Anthelmintic resistance in horses is an ongoing problem. Changes in methods of worming – from group worming to testing individual horses and worming appropriately – are important to help prevent any further resistance developing. There are various methods to test for worm burdens in horses, including faecal egg counts, blood tests and saliva tests. This article discusses these methods in relation to specific species of gastrointestinal parasites, in addition to how pasture management can be used to help maintain low levels of resistance.

Gastrointestinal helminths present a serious threat to equine health and welfare. Horses can be infected by a range of worms, most commonly the cyathostomins (small strongyles, small redworm). Other helminths of importance include the tapeworm (Anoplocephala perfoliata), the pinworm (Oxyuris equi), and, in foals and yearlings, Parascaris spp. The large strongyle (Strongylus vulgaris), a parasite that can cause severe colic, is rarely found in herds subjected to years of broad spectrum anthelmintics, but has been observed to ‘re-emerge’ in situations where use of these medicines has been reduced (Tydén et al, 2019). This parasite should still be considered in control programmes where there is low or negligible treatment frequency. Where horses are grazed with, or are on pastures recently grazed by, sheep or cattle, the liver fluke (Fasciola hepatica), should be taken into consideration, especially when there has been no opportunity to test or treat the ruminants.

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