Caution over parasites and spring turnout

Small strongyles (cyathostomins) in dung.
Small strongyles (cyathostomins) in dung.

Equine parasite experts are urging horse owners to remember that ‘one size doesn’t fit all’ when it comes to planning a worming strategy.

With spring turnout onto new grass just around the corner in the Northern hemisphere, now is a key time to think about the next steps for worming.

Check out Horsetalk’s 23-part parasite series

Wendy Talbot, Pfizer’s veterinary advisor, and the team at Pfizer Animal Health have put together six important tips to help horse owners.

“All horses respond differently to the same circumstances so it’s imperative to assess every horse independently as well as of a part of the group in which it is kept, when you plan your worming tactics,” she says. “We have put together six top tips to help you stay on track this year, to keep your horses healthy and performing at their best.”

  • Treat every horse as an individual within the herd and assess their age, health status and past history carefully. Horses with worms will shed eggs onto the pasture, as a part of the parasite’s natural life cycle. However, some horses will naturally cope better and shed less worm eggs. Conversely, some horses, especially debilitated or young animals, will pass more worm eggs in their faeces. These ‘high shedders’ can infect the pasture in a short space of time and consequently increase the pasture challenge to other horses that share their grazing, so it’s important to identify them and treat them appropriately. The best way to do this is with a simple worm egg count on the dung (Faecal Worm Egg Count).
  • Use fecal worm egg counts (FWEC) properly: Remember a single FWEC is only a rough indication of your horse’s worm burden at a specific point in time and results may vary between consecutive tests. FWECs are very useful for identifying which horses are shedding high numbers of eggs. Regular FWECs throughout the grazing season will in time build a clearer picture of your horse’s worm burdens and shedding patterns – it’s the best way to identify which horses need routine treatments and those which do not need worming every time.
  • Dose accurately: When you have identified that a wormer is needed you should always select the one most appropriate for the parasite you are targeting. You must also make sure you treat your horse accurately according to weight. This will help to maintain the effectiveness of the wormers available.
  • Keep your pasture clean: Clean grazing reduces overall worm burdens and reduces the need for excessive use of wormers. Poo pick regularly during the grazing season – ideally every day. If this isn’t viable, consider smaller paddock sizes so that each field can be alternately grazed, harrowed and rested. Cross-grazing with sheep and cattle is also effective at reducing horse parasite burdens on the pasture as they will ‘hoover up’ the worms without being affected.
  • Take advantage of the persistent effect of some wormers: Some wormers, such as those containing moxidectin, have persistency against cyathostomin larvae. For high risk horses, in some instances using these products at the beginning of the grazing season may well mean that your horse could provide a ‘clean up’ mechanism for the pasture for the first couple of weeks. This may reduce the overall worm burden on the pasture and in your horses, reducing the build up of worms over the grazing season and hence reducing the number of worming doses needed over the later summer months. It’s always important to take advice from your vet or SQP as to whether a wormer is required at this time for your individual horse.
  • Remember to strategically dose for tapeworm in the spring and autumn and for encysted small redworm and bots during the winter (do not rely on FWECs for these parasites).

Pfizer has a new App called Stable Mate which helps horse owners manage their daily equine healthcare regimes, including worming. Text Stable Mate to 80800 to download.


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