Hay is last summer’s grass. It is a new supplement and could also be called the original supplement. The purpose of hay is to add calories to the diet when winter is hard on the horses. Adding hay in winter to sustain life is the purpose of its creation. Adding hay when there is no pasture (drought, lack of pasture) is an inadequate substitute for fresh and healthy pasture. Here is why.

Most hay is created as a crop and is usually one grass or a mix of a few types of grass and legumes that were available only when the farmer could get into the field and harvest it. Therefore, while hay is a good source of carbohydrates in the form of starch, fats in the form of cellulose, and minerals, it is only a “good” source of protein (lacks all amino acids). Because of this, it is easy to overfeed hay because the horse will never feel satiated. The results cause increased body fat and protein loss (muscle loss, etc.). Please see the nutrition course to understand this process fully.

Another problem with feeding hay is that most horse owners feed it every day of the year, not allowing for the reduction of glucose intake needed to restore the health of the cell through hormesis. As a result, over time, the cell becomes exhausted from using glucose, which is a poor-quality fuel, and the cell becomes dysfunctional and dies.

Feeding hay has a place in the keeping of horses today. Unfortunately, the high land cost prevents adequate grazing land on most farms, thus requiring the supplementation with hay. Horses need to eat cellulose to survive, but supplementing the diet with all amino acids is necessary if hay (and pasture with only one type of grass) is the primary food source.

Feeding hay must be limited to horses that are “easy keepers” or are showing signs of Equine Metabolic Syndrome (EMS). There are three ways to do this. The most common way is physically limiting access to pasture and hay through limited turnout, a grazing muzzle or a hay net that retards the rate of consumption. Another way to restrict hay intake is to feed sufficient protein to activate satiation through the “Protein Leverage Hypothesis,” which states that a food-aggressive horse may not be hungry but is instead looking to meet their daily amino acid intake – something that will never happen if all they eat is hay. Finally, soaking the hay for an hour before feeding it will reduce the amount of sugar.

Eating hay through the “Nibble Net.”

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  1. Hi Dr. Tucker,
    Our mare Sassy has heaves and a local vet says a lot of horses in this area have allergic reactions to bahia grass and hay. Her pasture is a mix of grasses, but her hay has been bahia for several years. I found a local supplier that sells coastal and alicia (alecia) bermuda. However, there is a great deal of information online regarding bermuda hay being the vet’s best friend, suggesting bermuda causes a lot of horse to colic. I appreciate any insight you can share with me.
    Many thanks,
    Carol Pecot
    Amite, LA

    1. Heaves is a very complex subject. The first thing to do is to test her severity of heaves by performing a broncho-alveolar lavage (BAL) for a grade of 1 or 2 (treatable) or 3 or 4 (not treatable). If treatable then find the right medication that works for her and adjust the dosage to the minimum amount needed.

      Why did I start with the diagnostics? Because identifying the cause of the heaves is just about impossible but even if you did, if the allergic process has advanced into stage 3 or 4 then removing the cause or treating the disease is unrewarding.

      Heaves may be caused by the Bahia grass or it may be the molds on the grass or the lectins in the grass and all can be seasonal. Investigating this is frustrating because improving things usually requires the removal of several things in her diet even though it appears that only 1 thing caused an allergic event (worsening of the heaves).

      Finally, there are many people who won’t feed Bermuda hay and others won’t feed Coastal hay because of impactions caused by them. There are other horse owners who feed only these hays without problems. My thoughts are that the hay is digested by the bacteria in the colon and if those bacteria are not healthy due to the horse being fed grain and / or sugar then the horse is likely to have colic from these types of undigested hay due to their higher fiber content and less leaf content. This is only my belief because I believe there is no reasonable research done on this – only anecdotal observations.