Horse Feed Formulation: What Is a Premix?

Well-formulated horse feeds typically contain several ingredients: cereal grains, soybean meal, and molasses. Others might contain alternative energy sources such as high-fiber beet pulp or soybean hulls, or high-fat vegetable oil or stabilized rice bran. All of these feedstuffs contribute marginally to the vitamin and mineral profiles of textured or pelleted feed, but for many classes of horses, further nutrition is required for optimal health. Enter a premix.

As the name suggests, a premix is a blend of nutrients, primarily vitamins and minerals, which are not found in sufficient quantity in typical feed ingredients. A premix is added to commercial feeds to balance the vitamins and mineral profile.

Individuals charged with formulating feeds determine the sources of these nutrients. “Just as oats and corn can be of varying quality, so can the vitamins and minerals in premixes,” said Mike Lennox, formulation specialist at Kentucky Equine Research (KER). “The highest quality premixes contain ingredients that have the greatest bioavailability to horses, and therefore do the most to support vital body processes.”

Formulation experts know, for instance, there are several ways to fortify a premix with zinc, a micromineral that is important for many body processes, including carbohydrate and lipid metabolism. While it would be acceptable for feed manufacturers to use zinc oxide to nudge up zinc levels, equine nutritionists recognize the availability of other, more potent, sources. By way of example, zinc sulfate is a superior source of zinc, as evidenced by multiple research studies that have shown it is absorbed more completely by horses than zinc oxide.

Many minerals found in top-tier premixes—such as copper, zinc, iron, and manganese—undergo a chemical process that conjoins them with amino acids and peptides. “This process, called chelation, results in chelates, organic mineral forms that are more digestible than nonchelated minerals,” explained Lennox. Chelates are able to withstand a wide range of environmental conditions within the gastrointestinal tract, which maximizes their absorption.

The real beauty of a premix, according to Lennox, lies in the ability of feed manufacturers to evenly combine nutrients in large batches of feed. Certain vitamins and minerals, in particular, are included in such minuscule measures that it is advantageous to blend them with ingredients added in larger quantities, so they do not clump and concentrate in one part of a mixture.

Many feed companies will follow a two-step mixing process to ensure micronutrients are blended thoroughly in the finished product. First, vitamins and minerals are mixed fully with other finely ground ingredients and then made into pellets. Second, the pellets are added and combined with the feed for uniform distribution throughout a batch. With an eye on fine-tuned feed manufacturing, mills can be confident that every bite of feed will have the appropriate nutrition.

Why would horse owners concern themselves with the quality of a premix?

“Premix packs a punch,” said Kathleen Crandell, Ph.D., longtime nutritionist for Kentucky Equine Research. “The concept of delivering high-quality nutrients in a premix revolutionized feed formulation, allowing nutritionists to create diets more exactingly, which only elevates the well-being of horses, especially those with specific nutrient requirements such as high-performance horses and breeding animals.”

Have questions about your horse’s nutrition program? Ask a KER nutrition advisor for a ration evaluation today.