What are super fibers, and what are the benefits of feeding them?
Forages such as hay and pasture are well-known sources of fiber. Other feedstuffs are considered “super fibers” because they have energy levels much higher than typical forages. In fact, their energy values are only slightly less than those found in cereal grains such as oats and barley.
In the United States, the two most commonly fed super fibers are beet pulp and soy hulls. Dried beet pulp is often used as an ingredient in textured feeds, or it is added by the handful to a premixed concentrate to boost the fiber content of a ration. The seed coats of soybean seeds are called hulls and are very much like the thin, skin-like structure that surrounds peas. These feeds are more digestible than traditional fiber sources. For instance, hay is 40-60% digestible, depending on its quality, and beet pulp and soy hulls are 80% and 75% digestible, respectively.
Horsemen feed super fibers for a variety of reasons. Some horses will not or cannot eat large enough quantities of hay to fulfill fiber requirements. Dental problems, for example, may keep aged horses from consuming sufficient hay or pasture. When adequate forage consumption is an issue, caretakers should offer fiber in other forms. Horses on diets composed largely of concentrates (grains) may be unwilling to eat large amounts of hay. In these instances, fiber can be introduced into concentrates as beet pulp or soy hulls. Due to their high energy content, super fibers are also ideal for horses that have difficulty maintaining weight.
Some performance horses also benefit from super fibers, especially those asked to perform at moderate speeds for long distances such as endurance horses. In addition to being a steady energy source for horses, super fibers help maintain intestinal health. Consumption of fiber can increase water intake, creating a holding tank of water and electrolytes in the hindgut. This reservoir may prevent dehydration and electrolyte depletion during an exercise bout. Endurance horses, for instance, have only limited time to eat during a ride. An appetizing, fiber-rich meal, such as a slurry made of beet pulp, wheat bran, and grain, can supply the horse with sufficient energy and water to remain competitive.
Horses that do not tolerate diets high in starch may also benefit from super fibers. Horses afflicted with recurrent exertional rhabdomyolysis (RER) or polysaccharide storage myopathy (PSSM) often find relief when fed diets low in starch. When super fibers are fed to these horses, much of the energy necessary to support exercise is derived from fiber and not starch.