Horse Feeds: Understanding By-product Ingredients

A number of nutritionally valuable ingredients are actually by-products of other feed- and food-manufacturing processes. By-products are eyed suspiciously by some horsemen but, in reality, they are often high-quality source of essential protein, fiber, and energy for horses.

Soy and alfalfa are the major sources of protein (and essential amino acids) in horse feed, but they’re not the only ones. Certain by-products are valuable and economical protein sources that help to boost the protein content without drastically escalating the price of a product. These include:

  • Distillers dried grains (DDG) are both a protein and an energy source, and originate from grains such as corn, wheat, and barley. DDG are a by-product of distillery and ethanol production. Once a grain has been distilled (fermented by yeast) and the alcohol has been removed, the leftover product is dried and can be added to feeds as a low-carbohydrate source of protein. On average, DDG contain about 29% crude protein and 10% fat.

  • Wheat middlings are fine particles of wheat bran, germ, flour, shorts, and fines left over after flour production. Wheat middlings contain about 16-17% crude protein and provide a source of energy. They are frequently used for manufacturing pellets because the natural binding properties of wheat prevent crumbling. Wheat middlings contribute protein and energy to a concentrate while keeping pellets from falling apart.

Fiber is the base of every horse’s diet. While the majority of fiber should be coming from hay, hay products, or pasture, other sources of digestible fiber provide a source of nutrients for the microbial population in the hindgut. These fermentable fibers help beneficial microbes thrive which, in turn, helps ward off pathogenic bacteria, such as salmonella. Beet pulp, soy hulls, and oat hulls are examples of fibrous feed ingredients that are also by-products.

  • Beet pulp is an excellent source of digestible fiber that is the low-sugar, dried, cleaned residue from sugar beets.

  • Hulls, such as those from soy or oats, are also highly digestible fibers that support the microbial population of the hindgut.

Often swirling within the horse community is the notion that any kind of “hull” is just an inexpensive filler, but these ingredients have legitimate benefit to the horse’s digestive process. The microbes in the hindgut ferment these fibers to produce B-vitamins and volatile fatty acids, or VFAs, that the horse’s body uses for energy. The energy produced from VFAs can ultimately be utilized by the muscles during performance, potentially helping to stave off fatigue.

Have a question about a feed ingredient? Become an educated consumer! One way to do so is to contact a Kentucky Equine Research nutrition advisor.