The Scoop on Supplemental Feeding

An overview of supplement types and what they do for your horse
By Clint McKnight, DVM, photo courtesy Pilchuck Veterinary Hospital

Feeding the modern day equine isn’t as simple as providing hay, grain, and water. Today, horses are used in a variety of different disciplines, and depending on your horse's workload, nutritional requirements can vary greatly. Most horses require supplemental feeding to provide essential vitamins, minerals, and additional calories that forage alone may lack. Feed producers have addressed this issue by offering many different products for horse owners to choose from. With all of the products available, it can be difficult to determine which one is right for your horse.

Categorizing feed products into defined groups based on what they provide your horse and then determining the specific needs of your horse can help you decide. I generally break supplemental feed products down into grains (concentrates), beet pulp, fat supplements, and complete feeds (pelleted).

Grains
Grains are a common part of the equine diet, and the most frequently used include corn, oats, and barley. Although they do vary in composition from one type to the next, grains generally are high in energy (starch and sugar), low in fiber, calcium, vitamin D, and vitamin A (except yellow corn), and variable in protein content (8-12%). The type of processing used in grain preparation plays an important role in how well the horse can extract and utilize the nutritional contents. Whole grains are poorly broken down by the horse, and thus provide very little nutritional value. In order for the horse to most efficiently utilize grains, they should be rolled to break the outer hull, allowing access to the nutritional components within.

Beet Pulp
Beet pulp is generally classified as a forage because it contains about 18% fiber, yet it provides more calories than most hays (forages) pound for pound. This will provide your horse with a good source of energy as well as non-absorbable fiber. Beet pulp is the by-product from the manufacturing of table sugar. Because current extraction processes are very efficient, beet pulp contains little to no sucrose (table sugar) and provides most of its energy from soluble and insoluble fiber. This energy is released relatively slowly during hindgut fermentation and does not lead to rapid spikes in blood glucose, which can occur with concentrates. Beet pulp can be found in compressed pellets or shredded forms. Typical recommendations are to soak beet pulp prior to feeding, with pellets requiring longer soak time than the shredded form. Soaking is essential to prevent choking caused by the rapid expansion of the dehydrated beet pulp once it is exposed to fluid within the esophagus.

Fat Supplements
Fat supplements are products that can provide a higher caloric density in a smaller volume. This can be especially helpful for horses in high performance disciplines or “difficult keepers,” when providing enough calories to maintain weight with hay and grain alone is not accomplishable. Fat can also be added to the diet to keep calories up but allow for the removal of carbohydrate calories. This is particularly important when treating diseases like polysaccharide storage myopathy (PSSM), in which high carbohydrate and starch levels can exacerbate the disease.

Common products high in fat include high fat wheat bran, rice bran, and vegetable oils. Bran products contain very low levels of calcium and high levels of phosphorus (which binds to calcium and can create a calcium deficiency) and should be fed in conjunction with other feed products such as beet pulp or a complete feed. Some manufacturers have developed pelleted feeds that are >20% fat but balance the calcium, phosphorus, and other vitamins and minerals needed by the horse.

Complete Feeds
Finally, there are pelleted feed formulations referred to as complete feeds. The feed manufacturer has done the hard work for you by starting with a hay base, then balancing protein, carbohydrates, fats, vitamins and minerals for a horse’s particular needs in a palatable, easily digestible pellet. Most companies will have specific feed products designed for the stage of development, age, or workload of your horse. Other complete feeds help address medical conditions. This is important because there are distinct variations in protein, trace mineral and vitamin concentrations between various grass hays and legumes.

Which Type is Right?
Although good quality forage (hay) should provide the base of good nutrition, supplemental feeding is often required to provide the additional nutritional components needed for growth, development, and to maintain your horse's health and performance. Knowing what various products provide can help determine which is most appropriate for your situation.

Grains can be of great benefit to athletic horses, as glycogen replacement and storage is dependant on dietary glucose. Increasing the fat component of a diet can provide needed calories when trying to increase weight, reduce carbohydrates, or provide additional energy. Beet pulp is a good choice to incorporate with other feed supplements, providing increased fiber and calories without added starches or sugars. Complete feeds generally are the most effective choice when a balanced diet is needed, particularly in growing, athletic, and older horses. Low non-structural carbohydrate (NSC) complete feeds are also of great value in the treatment of equine Cushing’s disease, metabolic disease, and in storage myopathy cases.

There are always questions surrounding equine nutrition that should be addressed on an individual basis, so I recommend discussing your horse’s diet with your veterinarian. He or she can help determine if any adjustments need to be made.

About the Author
Dr. McKnight graduated from Ross University School of Veterinary Medicine in January 2004. He completed a medical and surgical internship at Pilchuck Veterinary Hospital, where he now works as an equine ambulatory practitioner.