Reducing Excitability in Horses Through Diet Changes

Can what you feed be making your horse a little crazy? The short answer is yes, it might be. Diets high in simple carbohydrates, like the sugars and starches found in some concentrates (those high in grain and molasses), can cause a horse to have hormone fluctuations that lead to anxiousness and excitability. While providing some simple carbs in the diet is important, when large amounts at a time are fed, the sugar rush eventually results in a crash and this fluctuation can make your horse a little nuts. When too many sugars/starches are fed in a single feeding, your horse’s digestive system can be overwhelmed. Simple carbs that can’t be digested and absorbed in the stomach and small intestine escape into the hindgut and cause imbalances that can lead to indigestion and even colic or laminitis.

Not every horse reacts in the same manner to a high-sugar diet, but if you have a horse that seems to be excitable and “high,” a diet change might help to calm him or her down. In some cases horses that have indigestion caused by a diet high in simple carbs will be anxious and irritable because they don’t feel well. A diet change can help remedy that problem as well.

Using fat and super fibers as an alternative energy source is the right direction to move toward. Fats are often described as “cool” feeds because they reduce excitability. Fats, such stabilized rice bran are digested at a much slower rate and don’t cause the hormone spikes associated with excitability. Fats contain more energy pound for pound than simple carbs so you can feed smaller meals and deliver just as many calories, if not more. As an added benefit, fats will not cause the hindgut overload that large sugar/starch meals can cause, reducing anxiousness, irritability and the risk of colic or laminitis.

As with all equine diets, fiber (hay, pasture, hay cubes or pellets) should be a major component. Fiber is digested in the hindgut and provides a consistent energy source. Fiber is critical to a balanced digestive tract and therefore the health and wellbeing of the horse. Super fibers such as molasses-free beet pulp provide an excellent source of extra energy for horses that tend to be “high.”

When trying to control sugar levels in the diet, manage pasture so that turnout occurs during times when sugar levels are at their lowest and feed hays with low nonstructural carbohydrates (NSC) values.

While simple diet changes will not alter your horse’s base personality, it might help temper it and reduce excess anxiety and excitability.



  • KA

    Hello. I’m reaching out for answers in regards to a new horse I have. 16 HH 15 yrs old quarter horse gelding. He was fed feed sweet, However he was a tad under weight when I got him a month ago. He was sold as s beginner safe horse. Things were going well… he actually had to much whoa so my trainer recommended amping up his grain intake and putting him on a higher fiber, fat sweet feed. He has definitely put weight on. BUT, he’s turned into a bucking bronc full of speed when lunging, riding in the round pen!! My trainer believes he’s a not a beginner safe horse at all! I’m questioning whether the increased amounts of higher levels of sweet feed he currently on is contributing to the change I’m seeing in him??? Any thoughts on this would be sooo appreciated!! Thank you

    • Karen

      Hello KA,
      There are several factors that can impact a horse’s behavior. Energy level is one of them. If a horse is thin and in negative energy balance, they are using all the calories they consume to fuel their basic functions and try to maintain a healthy body weight. The horse simply does not have any extra energy to expend acting silly. It isn’t unusual to see a thin horse labeled as “quiet” and then, lo and behold, when the horse gains weight and moves into a positive energy balance, they suddenly they have too much extra energy and they exhibit undesirable behaviors.

      It is certainly possible that the type of feed is contributing to your horse’s “hot temperament.” As discussed in the article, feeds that are higher in simple carbohydrates (starch and sugar) cause hormone spikes that increase excitability. A high-fat and high-fiber feed is more appropriate for a horse that becomes excitable, but you can provide too many calories even with a high-fat feed. When fed too much energy some horses get fat while others get hot!

      Not all feeds are created equal. You will need to look at the feed tag to determine what kind of ingredients are in your sweet feed.
      When you look at the guaranteed analysis, a high-fat feed will contain 6% or more fat and a high-fiber feed will contain above 12% fiber.

      For an adult horse, the protein level should be between 10% and 12%. (It is a myth that high protein makes a horse hot; it does not. Often the higher protein feeds also contained more energy, so the protein was blamed when it was really the higher energy levels that were the cause.)

      Look for an NSC (nonstructural carbohydrate) value of below 20%. The lower the better if you have a horse that is sensitive to sugars. You may need to call the feed manufacturer to get this number.

      When looking at the ingredient list on the label, a feed that is predominantly grains will be higher in simple carbs. A feed that is made with ingredients like dehydrated alfalfa meal, wheat middlings, shredded beet pulp, or soybean hulls will be higher in fiber. Rice bran, soybean oil, and flax are all sources of fat and are found at higher levels in high-fat feeds.

      Remember, the higher the percent fat, the more energy the feed provides; the higher the percent fiber, the less energy. It is often a balancing act.

      Another issue to consideration is turnout. Was the horse turned out 24/7 in his last home and now he is only turned out a few hours per day? Horses can burn off a lot of energy when they are turned out. Some horses become much hotter when they are cooped up in a stall or small pen for most of the day.
      Finally, it is always good to rule out any physical reasons for a change in behavior. Does the saddle fit correctly? Does the horse need his teeth floated? Is he muscle-sore for some reason? Is there an underlying neurological issue? Have your veterinarian give your horse a thorough physical exam to rule out any problems.

      Once you rule everything else out, it comes down to temperament. Some horses are just hotter than others. When they are healthy and fit, they just have more get up and go.

  • […] (sugars and starches found in whole grains and molasses) is important, this can lead to “hot” or excitable behavior. When necessary, these energy sources can be limited until they are needed to fuel top-level […]

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