Energy, Glycemic Index and Horses
By Eleanor Blazer
      The palms of your hands are sweating.

       There are butterflies fluttering in your stomach.

       Your knees are weak.  Are you in love?

       Yes and no!  You are preparing to ride the lunatic you love.

       And you are asking yourself, "Why does he act this way?"

       Does his training match your skills?  Is he a nervous "hot" bred horse - such as an Arabian or Thoroughbred?  Does he receive adequate exercise?

      The actual reason may be the quantity and source of dietary energy being provided in his daily diet.

      Diet, more often than not, is a major contributor to the behavior of hyper-active horses.

      But trying to fix the problems with diet alone will not work - unless you create such a deficiency in nutrients he becomes sick and weak.

      Energy is needed by the body for maintenance, reproduction, lactation, growth and physical performance.  The quality and quantity of the energy source will affect the horse's behavior.

      Horses are herbivores - they eat plants.  Plants use a process called photosynthesis to manufacture sugar.  The sugars from the plants are also known as carbohydrates. 

      There are three types of carbohydrates: simple, complex, and fiber.  The chemical profile of the carbohydrate determines how and where the horse will utilize the sugars within his body.

       Simple and complex carbohydrates, also called soluble carbohydrates, break down in the small intestine to glucose and glycogen, which are the main sources of energy for anaerobic work.  Examples of soluble carbohydrate are corn, oats, barley, and wheat. 

        Fiber is an insoluble carbohydrate.  It is digested in the large intestine or cecum. The beneficial bacterium within the cecum breaks down the molecules.  Volatile fatty acids are produced and absorbed into the bloodstream to be used as energy.  The remaining non-digestible material continues on its journey through the large intestine and is expelled by the horse.  Sources of insoluble carbohydrates are pasture and hay.

     Meeting the horse's energy requirements by using forage is the safest method.  But some horses require more nutrition than can be provided by using just hay or pasture.  Health problems may also necessitate feeding soluble carbohydrates.

      Trying to keep a horse level headed while providing enough energy and nutrients can be a challenge.  This is where knowing the glycemic index of a grain or product is helpful. 

     The glycemic index is used to compare the simple sugar content of feed sources.  Feeds with a high glycemic rating break down in the small intestine quickly.  The blood glucose levels rise and can make some horses react in a "hot" manner.

     California State University concluded a study of 16 popular feeds used in horse diets.  Oats were given the glycemic rating of 100 and the other feeds were scored according to where they fell in comparison to the oats.  A group of horses were fed the 16 feeds at different times and blood glucose levels were checked.  The results follow:

                                       Corn:   117                              Carrots:   51
                                       Oats and molasses:  105          Wheat bran:   37
                                       Barley:   101                            Timothy hay:   32
                                       Oats:   100                               Alfalfa cubes:   30
                                       Oats and oil:   86                     Alfalfa hay:   26
                                       Alfalfa and molasses:   85        Bermudagrass:   23
                                       Wheat:   71                              Rice bran:   22
                                       Vetch blend hay:   53              Beet pulp:    1

       Using this study, you can scientifically determine what feeds can spike the blood glucose levels of a horse.  When molasses is added to oats the glycemic index increases.  Notice the grain with the highest level is corn.  This observation can lead to the conclusion that popular sweet feeds which contain corn and molasses will raise the blood glucose level of horses. 

      When oil is added to oats the glycemic rating drops!  This supports research that oil (fat) as an energy source is good for performance horses that need to stay calm.  

      Why does a spike in blood glucose levels make some horses hyperactive?  Glucose is the only food the brain can utilize.  Some horses are affected by the highs and lows of the fluctuating glucose levels.

      Energy is only a small part of the balanced equine diet.  Protein, vitamins, and minerals must not be neglected.  When choosing a horse feed be sure to pick one that provides the nutrients which are lacking in the forage.  Then look for a feed that gets most of its energy from fat and fiber.  Choose a product from a reputable company and follow the feeding directions.

        Proper nutrition and management practices can prevent many problems associated with caring for horses.  You can learn how to provide your horse with a better life-style by taking the online course "How to Feed for Maximum Performance" taught by Eleanor Richards Blazer.

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