Soaking Hay to Reduce Sugars


We often hear of the practice of hay soaking for horses with heaves (to reduce dust particles), but did you know that hay soaking is often beneficial for horses diagnosed with metabolic conditions?  When you soak hay, the water actually leeches out some of the sugar content making it safer for some horses.


horse hay


If your horse has been diagnosed with or is at risk for one of the following conditions, you’ll need to pay attention to the sugar/starch levels in his hay and soaking may be called for:

(Note: soaking hay also reduces potassium levels considerably, which is important for horses with HYPP.)

Pasture grazing often needs to be reduced or sometimes eliminated for horses with metabolic conditions, so they will need to get their forage needs met from hay.  Getting your hay tested is always best–that way you aren’t guessing about the sugar and starch (or mineral) levels.  I’ve been getting mine tested for about 5 years now through a company called Equi-Analytical.  It’s actually pretty painless.  (See these posts on taking a hay sample and taking a pasture sample.)

I have two mares that are insulin resistant, so I always check my sugar and starch levels in my hay.  They’re usually okay, but one year, I did have to soak my hay.  Hay that tests at or below 10% NSC (Non-structural carbohydrates)–which is found by adding WSC (water-soluble carbs) + starch– is safest for these horses.  If it’s higher than 10%, soaking it can reduce these levels.

I wrote an article for The Horse a couple of years ago, entitled: Soaking Hay: How Much Sugar is Actually Removed?  It was based on a study performed in the U.K. and here are two significant finds from the study:

  1. Soaking hay for 20 minutes resulted in the lowest WSC reduction (5%), while soaking hay for 16 hours resulted in the highest WSC reduction (27%).
  2. The effects of soaking on crude protein varied some, but were not significant.

So the longer you soak your hay, the more the WSC levels will be reduced–and you don’t need to worry too much about the loss of protein from soaking.

Soaking Procedures

Here is what I did to soak my hay a few years ago:

  1. Use a large tub filled with water.
  2. Put hay in a hay net and completely submerge in water.
  3. Soak for desired amount of time (I soaked for about an hour or two.)
  4. Remove hay and feed immediately (as it can mold.)
  5. Dispose of ‘liquor’ in a grassy areas where horses do not graze (remember, it’s full of sugar) and do not always dispose of it in the same location–it’s basically an environmental pollutant.

If you want to know the exact NSC levels of your soaked hay, you can always get it tested after soaking it.

Here are a few resources if you’d like to read more on soaking hay:

Hay Soaking: All Washed Up or a Good Management Option?

With Horse Hay, Wetter Can Be Better

Hay Soaking

Also, you might want to check out this post on low NSC feeds.




Hi! My name is Casie Bazay. I'm a mom, a freelance writer, and a certified equine acupressure practitioner.

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6 Responses

  1. Robynne Catheron says:

    This is really helpful, thanks! I read somewhere that if you soak hay in hot water, it only has to soak for about 15 minutes. Do you know if that’s true? Maybe I read that on, I can’t remember 🙁

    • then5925 says:

      Hi Robynne,

      Yes, I’ve heard that soaking hay in hot water will reduce sugars faster. On Dr. Kellon’s Equine Cushings/ Insulin Resistance yahoo group, they recommend soaking for 1 hour in cold water or 30 minutes in hot water. Getting hot water outside wasn’t feasible for me though, so I just used cold. is a great resource too!

      • Robynne Catheron says:

        That’s what it was, thanks! Also, did you know about steaming hay to eliminate dust and mold? Horse and Man dot com has a DIY steamer with great instructions for making a whole-bale steamer out of s Rubbermaid tote and a little portable bathroom steam cleaner. I can’t remember the title, but it shouldn’t be too hard to find. She has an awesome daily blog, btw 🙂

  2. Susan Deakin says:

    This is all well and good but what do we do when we have several horses that need soaked hay and it’s below 0 degrees outside????!!!

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    • then5925 says:

      Hi Susan–that would be tricky. Maybe you could soak the hay in a garage or somewhere where it’s warmer. Or you could make/ purchase a steamer. I’m not sure how they would hold up in cold weather, but that’s another option. I get my hay tested and I’ve only had to soak one batch so far.

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