If you have a horse that is overweight or has equine metabolic syndrome, you may have heard that your horse needs to be on a low-carb diet. However, Dr. Clair Thunes from Sacramento indicates in the Horse magazine that there are different types of carbohydrates and it is important for horse owners to know the difference. All horses need carbohydrates but there are two basic types: starch or sugars, such as glucose; and complex carbohydrates, such as cellulose, hemicellulos, pectins, and lignin. The complex carbohydrates are digested in the hindgut by bacteria and do not result in increased levels of insulin, whichare the cause of laminitis and founder.
However, all forages contain some simple sugars and complex sugars so you have to make sure you are feeding forages that are low in starch and sugars that are also called non-structural carbohydrates. The problem with green lush pasture grass in the spring is that it is high in non-structural carbohydrates. We use to feel most cases of founder were related to feeding large amounts of grain or accidental ingestion of grain, and although this does occur, it is fairly rare. By far the most common cause of laminitis and founder is when horses that are susceptible to founder graze on lush spring pasture. So if you have a horse that is overweight or has equine metabolic syndrome, they cannot graze on lush spring pasture. Now this does not mean they cannot be turned out, but must be in a basic dry lot and fed low-starch hay and low-starch grain. It is not a good idea to stall these horses so fencing off an area that has no or very minimal grass is ideal. Some horses can use a grazing muzzle to decrease consumption of pasture grass, depending on the situation.