Have you ever arrived at the barn and found a fellow barn mate submerging their hay in a container of water? It may seem a little strange, but there is an entire area of equine research that has focused on the benefits of soaking hay for some horses.

Horses with Equine Metabolic Syndrome and PSSM Type 1 require a low non-structural carbohydrate (NSC) diet. Non-structural carbohydrates are the combination of starch and sugar. The types of sugars measured in forages are water soluble carbohydrates (WSC). For many horses, forage is the primary source of NSC in their diet.

Soaking hay in water leaches some of the NSC from the hay, possibly making it safer for the horse that is sensitive to NSC in their diet. While soaking hay will decrease NSC, it does not guarantee it will decrease it to a low enough concentration for all horses, depending on how high the NSC of the hay is before soaking. For that reason, it is beneficial to have hay tested before soaking and after soaking.

Soaking hay is also a method to decrease mold spores in hay, which may benefit horses with Equine Asthma. Care should be taken with this approach, as adding moisture can encourage more mold growth and cause further health complications. Hay that is soaked for the purpose of decreasing mold spores should be consumed in a short period of time after soaking, especially in hot weather.

How Long to Soak Hay to Remove Sugars?

Hay should be soaked in cool water between 15 and 60 minutes and then fed right away to prevent the growth of mold. Soaking for up to an hour can reduce sugars up to 30 to 40%. Soaking hay for longer than 60 minutes may remove more sugars, but after 60 minutes, the undesirable loss of other nutrients begins to occur. Mineral losses begin after 60 minutes, but most important, the fiber components of the hay also begin to leach out of it.  

How to Properly Soak Hay

To properly soak hay, it should be submerged in fresh, cool water. A trash can or large bin can be used for this purpose. Many people find it easiest to place hay into a hay net and then submerge it in water. Rinsing the residual water from the hay after soaking will help remove any additional sugars and the water should be disposed of after each session of hay soaking.

Should You Soak Your Hay?

Soaking hay can be very helpful to reduce NSC content; however, testing hay beforehand is recommended. If the hay is already lower in NSC (<10%), soaking is unnecessary. On the contrary, not all hay that is soaked will become low enough in NSC to be appropriate for horses with NSC sensitivities.

The varying structural composition of hay impacts how much sugar will be removed by soaking, therefore, it is difficult to give a firm cut off for the number at which hay is too high in NSC to be safe, even if soaked. As a rough rule of thumb, hay that tests greater than 14% NSC (WSC + starch) should be tested post-soaking to ensure that NSC is decreased adequately.

Soaking hay also has the downsides of being labor intensive and requires the hay to be consumed quickly to prevent mold growth. A guaranteed low NSC, commercial bagged forage is an alternative option for horses that need a low NSC diet.

If you have questions about your horse, contact us for a free, personalized feeding plan!
 

Nicole Rambo, Ph.D.