We have all seen the large containers on yards containing a murky black liquid ready for soaking hay overnight, and we have all seen owners spraying filled hay-nets with the hose pipe for 30 seconds. So in the management of laminitis, polysaccharide storage myopathy, hyperkalemic periodic paralysis and chronic obstructive pulmonary disease, which is the correct method?
Recent research has shown that hay should be soaked in clean fresh water for one hour, half this time if the water is warm. Owners may assume that the longer they leave the hay to soak, then it increases the chance the water will remove every last shred of damaging substance the hay may contain. However they are also vastly reducing the amount of nutrients and minerals that their horse needs to stay fit and healthy.
Further to this if you are soaking hay to remove sugars and starches as part of your horse’s condition management, laminitis for example then they still need carbohydrates in their diet. Aim to reduce the levels of sugar and starch, rather than removing them completely.
All horses, even diseased ones, require carbohydrates in their diet. The very low nonstructural carbohydrates (NSC) content in hay soaked for greater than 1 hour, combined with increased fiber amounts (fiber components are not water soluble, thus they become more concentrated in soaked hay), brings into question the palatability and availability of nutrients in hay soaked for longer periods of time (Martinson K et al 2017).
Chewing on hay that has been soaking for a number of hours must be the equivalent of humans chewing on wet cardboard, both in taste and nutrient content. The other thing that occurs is that soaking wet hay-nets get hung up to drain and left, even all day or night. This is somewhat baffling considering the hay may have been soaked in order to remove harmful dust, yet is then left as the perfect environment for the production of mould, the spores of which can produce similar symptoms to the condition the owner is trying to manage.
Consider what the water contains once the hay is removed. Everything that has been leached out by the water is now a biological, chemical, dusty and dirty soup. Replace this water (responsibly) with clean water as opposed to re-using the same water to soak another hay-net in.
Give more thought to what you are feeding your horse. While going to great lengths to care for them you may unintentionally be damaging their health by feeding unpalatable, nutrient poor, mouldy hay.
Martinson K, Hathaway M, Jung H, Sheaffer C (2017) Hay soaking: all washed up or a good management option? University of Minnesota [ONLINE] Available at:
(Accessed 25th September 2017)