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Soaking hay helps to reduce the water-soluble carbohydrate (WSC) or ‘sugar’ content and of course less sugar means fewer calories so it can be a useful tactic to deploy if you want your horse or pony to lose weight! However, WSC losses are highly variable which means soaking can’t guarantee suitability for laminitics.

Hay soaking tips

  • Always use fresh water.
  • As a guide, soak for 1-3 hours in warm weather and 6-12 hours in cold weather.
  • Increase the amount of hay you soak by approximately 20% to compensate for the loss of dry matter.
  • Make sure your haynet is fully submerged in water.
  • In hot weather, ideally soak your hay out of direct sunlight.

Dry matter losses explained

All forage contains some water (which doesn’t count towards the horse’s forage intake) – the portion that’s left is described as ‘dry matter’. Due to the loss of nutrients (and therefore dry matter) into the water, each slice of hay will contain more water and less ‘hay’ post soaking. For example, a net of hay weighing 7.5kg kilos may contain around 6.5kg of dry matter or ‘actual hay’ before you soak it, and only 5kg after you soak. As a practical guide, increase the amount of hay you soak by 20% to compensate – this will help you to ensure you don’t restrict your horse’s forage intake too severely.

Soaking vs steaming

Steaming your hay is by far the superior option if you’re concerned about respiratory health but it has little effect on WSC levels. Although not a practical solution for many owners, soaking followed by steaming (in a commercial steamer) helps to achieve the best of both worlds if you are trying to reduce the level of ‘sugar’ in your hay and improve hygienic quality. Did you know straw can be steamed before feeding to improve the hygienic quality?

What if my horse is prone to laminitis?

If your horse is prone to laminitis, ideally have your forage analysed (by the wet chemistry method) and use soaking as a back-up. Forage for laminitics should contain less than 10-12% non-structural carbohydrate (NSC: WSC + starch) on a dry matter basis. However, as UK forage consistently contains very little starch (around 2% or less), testing for WSC rather than NSC is often sufficient.

For more specific advice, you can contact the SPILLERS™ Care-line on 01908 226626 or visit

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