Planning a diagnostic-led worm control programme
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By Dr Corrine Austin (Austin Davis Biologics) and Prof Jacqui Matthews (Roslin Technologies)
Planning a diagnostic-led worm control programme
All horses are exposed to worms while grazing, but how we control these parasites is essential to horse health and performance. Most horse owners are aware of testing to determine whether their horse needs deworming. The tests comprise faecal worm egg counts (FEC) for redworm/roundworm detection and saliva testing to detect tapeworm infections (standard FEC methods are unreliable for tapeworm). Until now, encysted small redworm larvae have remained undetectable as FEC only determines the presence of egg laying adult worms. This has meant that routine winter moxidectin treatment has become recommended practice to target potentially life-threatening burdens of small redworm encysted larvae. Excitingly, a new small redworm blood test is being commercialised* which detects all stages of the small redworm life cycle, including the all-important encysted larval phase. Together, these tests offer a complete worm control programme for common horse worms using diagnostic information. This is known as ‘diagnostic-led worm control’ (see Figure 1 for common worms in horses). Essentially, testing is used to tell you whether your horse needs deworming or not.
Common horse worms
Why should you use testing to determine whether you should use dewormers or not?
Gone are the days of routinely administering dewormers to every horse and hoping for the best. That strategy is outdated as it has caused widespread drug resistance in worms (i.e., worms are able to survive the killing effects of dewormers and remain in place after treatment, which can lead to disease and in worst cases, death). To reduce the risk of further resistance occurring, we need to ensure that dewormers are only used when they are genuinely needed—when testing detects that horses have a worm burden requiring treatment. Regular testing also helps identify horses likely to be more susceptible to infection and thus at risk of disease in the future.
How to plan your horse’s worm control programme ….