All horses need fiber in their diet and some of it must be the form of long hay. Horses challenged by metabolic syndrome should be offered hays that are low in non-structural carbohydrates or NSC. This class of carbohydrates includes starch, water-soluble sugar, and fructan.
Normal horses can tolerate NSC levels of 20% or higher. It is recommended that horses with metabolic syndrome consume hay with NSC levels of around 10% to 12%.
In order to know the true NSC value of your hay you will have to test it, but understanding the factors that affect NSC levels will help you pick a hay that is more likely to meet your horse’s needs. Several factors affect the NSC levels found in a cutting of hay. Multiple cuttings from the same field of grass can yield hay with different levels of NSC. The type of plant, maturity when harvested, time of cutting, time spent curing in the field, and environmental conditions during harvest all contribute to the amount of NSC found in the plant. When choosing hay for a starch/sugar sensitive horse, you have to consider all these factors.
Typical NSC levels in different types of hay*
Grass hays: average of 12% (range 7%-18%)
Legume hays (alfalfa and clover): average of 15%
Oat hay: average of 22%
2. Spread the hay — make horses walk to multiple small piles in the field to increase exercise.
3. Soaking hay— this can lower Carbohydrate levels and as a bonus has been shown to decrease allergens in “heave” horse reactions. At times this is not practical in cold weather — you get a “hay sickle” in the bucket — the water freezes into ice. This is a great time to test hay in fall when you are stocking up to feed it in the winter. If it has low ESC/sugar/starch you will not need to soak it. Also, test your horse’s Insulin level after a few days on the new hay. This will let you know if all is OK. Most Laminitis is via fresh grass and not hay. Pasture-associated Laminitis accounts for 54% of Equine Laminitis. (USDA Lameness and Laminitis National Health System 2000)
4. What hay to feed and what levels do I look for if tested?
Timothy Grass Hay – Good choice, easy to get. If tested, want 8-12% protein, low end of normal range of ESC (Simple Sugars) that is 4.7-10.9%, and low end of normal range of starch that is 1.5-4%. Example: If 15% ESC and 6% starch, do not buy it – probable Laminitis trigger. If it is 5.7% ESC and 1.8% starch is OK to buy and no need to soak.
Alfalfa Hay – Can mix with Timothy up to a 50:50 ratio. It has a slightly lower ESC, starch, and sugar than Timothy Hay. The Equi-Analytical web site has a printout showing its safety. If someone tells you Alfalfa is a problem in Insulin Resistant horses, they do not have the facts. ESC is 4.2-8.2% Starch is 0.8-3.2%. I usually will not go above a 50:50 ratio because higher amounts of Alfalfa seems to cause more gas and runny manure.
Orchard Grass Hay – Very similar to Timothy Grass Hay. A good choice.
Teff Grass – Tests we have run show it to be safe on sugar and starch, so, again, it is a good choice, When you test, you want similar values as Timothy. Can have mixes of Teff with Orchard or Timothy.
Bermuda or “Coastal” Hay – These have double the starch of Orchard or Timothy, so you would need to soak these overnight and during the day prior to feed. 6% starch average, range 3.1-9.0. Since most Bermuda Hay is fed in the south, freezing “hay sickles” will not factor in. Timothy, Orchard, Timothy/Alfalfa, Orchard/Alfalfa are better choices.
Avoid Totally: Wheat hay, Oat hay, Barley hay – all very bad. Huge starch.