Creating the Right Mix: Understanding Nutrients in a Horse's Diet

One of the most important aspects of keeping your horse healthy is feeding a balanced appropriate diet. But similar to the options you might find in a grocery store for your family the options of what to feed your horse can seem overwhelming. Understanding what nutrients are found in specific types of forages and grains can help you decide the best diet for your horse.
The six nutrient classes
A nutrient is something that is consumed in the diet and is essential to the animals body. You will find a variety of nutrients in every feed and forage given to a horse but the specific amount and types of nutrients will vary. There are six key classes of nutrients carbohydrates fats proteins vitamins minerals and water Figure 1. Lets review each class of nutrients and explain why they are important for the healthy horse and where in the diet you will find them.

Carbohydrates
Carbohydrates are one of the two main sources of energy for the body. Carbohydrates also provide fiber to the diet. There are many different carbohydrates and they can be categorized in several ways Figure 2. One way is to consider their chemical structure and whether they are used to create structure for a plant or not. For example hemicellulose and cellulose are complex large carbohydrates used to maintain the structure of a plant. These carbohydrates are known as structural carbohydrates and give plant stems their rigidity. When we think about fiber in the horses diet hemicellulouse and cellulose are a big part of that fiber component. Structural carbohydrates are digested by microbes in the horses hindgut. When we analyze feed for carbohydrates cellulose and hemicellulose are measured in acid detergent fiber ADF and neutral detergent fiber NDF.
On the other hand glucose and fructose are very small carbohydrates and are examples

of simple sugars. This molecule is not used for plant structure but as an energy source both for the plant and the horse that eats it. There are also more complex sugars such as disaccharides two simple sugars bonded together oligosaccharides 310 simple sugars fructans a long chain of fructose sugars and starch a long chain of glucose sugars. All of these molecules provide energy and are considered nonstructural carbohydrates NSC. These carbohydrates are found in all plants but are particularly high in grains such as corn oats barley etc. They are digested in the horses foregut the small intestine specifically. When analyzing feed these nonstructural carbohydrates can be measured as part of several different fractions including ethanol soluble carbohydrates ESC water soluble carbohydrates WSC or simply as NSC.
Carbohydrates are key components of plants and so it is really impossible for a horse to have a lowcarb diet since their whole diet is made of plants. From pasture grass to hay to oats and pelleted feed carbohydrates are everywhere in a horses diet. It is possible to create a diet for a horse that is low in NSC. This is needed for horses that have metabolic issues such as chronic laminitis or metabolic syndrome. But for a healthy horse with no diagnosed metabolic issues NSC is an important source of energy in the diet.
Fats
Fats are the other key source of energy for the horse. In fact fats provide approximately three times as much energy as carbohydrates dowhich can be a good thing or a bad thing depending on the horse. For a horse that is working hard or needs to gain a little weight fat in the diet can be very helpful. For a horse that is overweight fat might not be needed. Beyond providing energy to the horse fat