Anyone who has made an effort to read the label on a bag of horse feed knows that recognizing and understanding the ingredients is not easy. We know that three basic feed components — protein, fat, and fiber — are necessary in a horse's diet, as well as various vitamins and minerals, but what ingredients contain which nutrients?
Let's start with the basics.
Oats are the first ingredient people think about when it comes to horse feed. Oats are a source of protein and starch, and they are high in fiber. One caveat about oats is that they also are high in phosphorus, but low in calcium. Because the horse's diet should have a greater ratio of calcium to phosphorus—about two to one—a feed that is primarily oats needs to have a calcium source added to it. This can be ground limestone or calcium carbonate.
Corn is a high source of energy in the form of starch, but even when cracked or ground, it is only about 45 percent digestible, which can cause problems.
“The risk of corn ending up in the hindgut is higher,” nutritionist Dr. Juliet Getty said. “If that happens, then the bacteria will ferment it and we could have cecal acidosis or a toxemia situation, which is one cause of laminitis.”
Corn has other drawbacks. It is high in omega-6, which is an inflammatory, and mishandling of corn can cause moldy corn poisoning. Getty suggests substituting an equal amount of oats or barley for corn, and she advises horsemen not to use corn oil in their feed as a fat source.
Distillers dried grains (DDS) are a byproduct of a corn-and-yeast fermentation, often added to feed to increase the protein and vitamin B content.
Soy products are a staple in horse feed as a source of protein. Soy oil is a source of fat. Getty is especially opposed to using soy products in horse feed for two reasons: they are highly inflammatory, having four times the ratio of omega-6 to omega-3, an anti-inflammatory; and 99 percent of soy is genetically modified so it can withstand spraying with the herbicide glyphosate (Round-Up), which kills beneficial bacteria in the gut and reduces the absorption of certain minerals. Getty recently has begun testing for glyphosate in some chronically sick horses, and she has found high levels of the herbicide. When she changed the diet to eliminate glyphosate sources, most of the horses recovered.
Rice bran is a high-fat supplement for horses. Be sure the label identifies it as “stabilized rice bran.” Raw rice bran goes rancid within 48 hours and can be a vehicle for botulism, E. coli, and other harmful pathogens.
Wheat middlings are the byproduct left over after processing wheat into white flour. During processing, wheat middlings must be subjected to high temperature and pressure to keep them from causing impaction colic. For this reason, they are a common ingredient in pelleted feed. Wheat middlings are a source of protein and fiber.
“Alfalfa pellets or alfalfa meal is a good source of protein,” Getty said. “Ground flax is a good source of protein, and it's high in omega 3 as well.”
Beet pulp is a source of calcium and water-soluble fiber. When it is soaked before feeding it, beet pulp creates a gel that is soothing to the digestive system. But it also is high in iron, which can be problematic for a horse that is overweight or has insulin resistance. Getty recommends rinsing the beet pulp before soaking it to remove as much iron as possible.
“All horses need iron,” Getty said, “but there is so much iron in forages that adding more iron to the diet can really mess up the amount of copper and zinc the horse absorbs.”
Molasses is sugar, and sugar causes inflammation. Its primary purpose in horse feed is to stick everything together and to make some feeds more palatable. Getty discourages horsemen from feeding molasses unless it is absolutely necessary.
Ethylenediamine dihydriodide is a source of iodine, which regulates the thyroid gland and fights fungal infections such as white line disease of the hoof and certain skin diseases.
Butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) are chemical preservatives to keep fats in horse feed from becoming rancid for up to a year. Tocopheral, a form of vitamin E, is used as a natural preservative. Propionic acid, sodium benzoate and potassium sorbate are other natural preservatives.
Getty said the healthiest way to feed a horse is to go back to nature.
“If you want to do the best thing for your horse, investigate the use of more natural feedstuff,” she said. “More and more companies are developing more natural lines that have fewer ingredients, fewer preservatives, non-GMO products, staying away from corn and soy. That would be the best for your horse.”
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