Asked July 20, 2020, 4:39 PM EDT
Can I feed a horse grass hay that has foundered
Barry County Michigan
Forage is a horse's primary source of energy. If a horse has experienced pasture associated laminitis, then they need a hay that is low in starch and sugar content. Cool season grasses like our Michigan brome, orchard and Timothy, typically have higher sugar content than warm season grasses. When selecting hay for a foundered horse, you will want to look for a more mature grass or grass/alfalfa mix with low sugar/starch content. When selecting hay for a laminitic horse, consider testing your hay for sugar and starch. Equi-Analytical is a good lab to consider: https://equi-analytical.com
When feeding a horse with metabolic syndrome or Cushing's Disease, you want to select a hay with an ESC + Starch value < 11 on a dry matter basis. ESC stands for ethanol-soluble carbohydrates and is one measurement used in forage analysis to determine the amount of sugar present. Soaking hay is a common practice for people concerned with sugar and starch levels in their hay. Soaking hay for 60 minutes will decrease sugar levels by 20 - 30%.
Many veterinarians and their clients are more familiar with Non-Structural Carbohydrates (NSC), a calculated value that accounts for more of the sugar fructan in the hay. It is thought that some horses with pasture associated laminitis have a high sensitivity to the sugar fructan. NSC is calculated by adding Water Soluble Carbohydrates (WSC) + Starch. Owners feeding horses prone to laminitis are typically looking for NSC values < 12 - 13% on a dry matter basis.
There is still some different opinions over what are tolerable sugar and starch values in hay fed to horses that are prone to laminitis. Research is ongoing to get a better handle on how to feed these horses, but we do know that hay should be the mainstay of their diet. A hay analysis is very helpful in selecting and feeding hay to a foundered horse. I have included a few articles that may help shed a little more light into sugars in hay fed to horses as well as what the typical horse person is looking for in a hay analysis.