SOAKING HAY and STEAMING HAY

Soaking Hay and Steaming Hay…What’s the Difference?
There is a large population of horse owners who soak their horses hay for multiple reasons, but
most often to reduce dust or to decrease NSC (non-structural carbohydrates) in the hay. The
most obvious downside to soaking is that it is messy, time consuming, reduces the nutrient
content, and the hay often becomes less palatable to the horse. The BIG question is, how long
do you soak your hay? If you ask 20 people how long they soak their hay and in what
temperature of water, you are likely to get 20 different answers. So, it is clearly a problem that
there is no standard or continuity on how to “condition” the hay for the desired result.
One of the most important things to keep in mind is that hay is a dynamic feedstuff. There is no
“guaranteed analysis” on each bale like there is on a bag of concentrate. Therefore, if you want
to know what percent of WSC the hay has, it MUST be tested. There is no easy way around that.
Now, at this time, conventional wisdom extrapolates that metabolic horses such as those with
insulin resistance and Cushing’s have a desired NSC (WSC + starch) of 12-10% or less. So, the
recommended strategy to feed those horses is to get a hay type that is already “low” in NSC so
that steaming or soaking can reduce the NSC to the target percent (12-10%).
Recent research performed by Kentucky Equine Research (KER) has shown that steaming hay can
decrease the NSC up to 7%. With that said, if the percent of NSCs of your hay was known
(assuming it was tested), steaming could potentially be a viable option to decreasing NSC for
the metabolic horse. This is with the assumption that the NSC of the hay is low and that a 7%
decrease could put the forage into the range of 12-10% NSC. Of course, further research and
data will be needed to confirm this option.
The major take home points about steaming vs. soaking are the following:
Soaking
Steaming
1. Decreases NSC
(depending on time and water temp,
decrease can be from 20-30%)
Decreases NSC
(Further research needed but
decrease can likely be from 7-10%)
2. Decreases nutrient content
Maintains nutrient content
3. Difficult to do, no standard protocol
Easy to do, standard protocol
4. Low palatability for horses
Highly palatable for horses
It is important to remember that a complete and balanced diet along with exercise is the only
way to manage horses regardless of their metabolic state. People often get stuck on singular
numbers and ideas and it is necessary to maintain the “whole horse” perspective to give them
the best nutrition in able to thrive in whatever they do.
Stephanie Davis, DVM

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