Why Go Grain Free: Grain-Free Diets for Horses

By Devan Catalano, Phd / 4 October, 2021

Has your trainer or barn friend transitioned their horses to a grain-free diet? Heard about the idea of it online? Feeding your horse a grain-free diet has become increasingly popular. Let’s talk about it—what does it mean, which horses could benefit from a grain-free diet, and which might not.

First, let’s define what grain is. True grains are the seeds produced from cereal crops including:

• Oats

• Wheat

• Barley

• Corn

• Rye

• Rice

• Spelt

• Teff

• Triticale (a cross between wheat and rye, pronounced “tri-tuh-kay-lee”)

Oats, wheat, barley, and corn are the most commonly used grains in horse feed. Corn is classified as a grain by the USDA when it is harvested fully mature and dry. Since this is how we use corn for horse feed, for all intents and purposes, it’s a grain.

Grains are made up of four main parts: the hull, bran, endosperm, and germ. The germ is what develops into a future plant and contains mostly fats and vitamins. The endosperm is the part of the grain that fuels germ growth and development and consists mainly of carbohydrates (in the form of starch) and protein. Both the bran and hull are rich in fiber, as well as vitamins and minerals.

What does it mean to have a grain-free diet for horses?

While there is no official definition for this, grain free generally means that a product is free of whole grains that contain the starchy endosperm portion of the seed. You may still see parts of the original seed in a grain-free formula, such as hulls. This is allowed because a seed hull is defined as a part of the original grain and thus a by-product. If you are avoiding grains because of an allergy, it is important to carefully read the ingredient list. Hulls and oils are often safe, though, as they do not contain protein, which is the primary cause of a grain allergy. If you are avoiding grains because you are seeking a low starch formula for your horse, don’t fret if you see “oat hulls” or “rice bran” in the formula as these are parts of the grain or seed that are significantly lower in starch, and higher in fiber.

What happens nutritionally in grain-free horse feed?

Think of nutrients as a pie chart. All of the pieces must be accounted for—if carbohydrates are reduced, that space must be replaced with something else. In a product with a low feeding rate, like a ration balancer, that space is typically filled up with more of a high protein ingredient like soybean meal. This works because concentrated protein is a target goal for any ration balancer.

In a product with a higher feeding rate, like a complete feed, we have a second consideration beyond filling up the pie chart—how do we replace the calories provided by carbs? Protein is not an ideal source of energy, and there are limitations to both how much fat horses can digest and how much fat we can incorporate into a pelleted feed. The solution? Fiber! Fiber rich ingredients like alfalfa, beet pulp, and soy hulls provide balanced energy that will fuel horses without causing spikes in blood glucose and insulin the way a starch-heavy meal does. Most grain-free products that are designed to be fed in greater amounts will be high in fiber. This will be reflected in the crude fiber, acid detergent fiber (ADF), and neutral detergent fiber (NDF) values listed on a guaranteed analysis.

What horses benefit from a grain-free diet?

There are a variety of horses that can benefit from going grain free. On one end of the barn, such horses include: easy keepers in general, overweight horses or ponies, and horses with insulin resistance. These are horses that need carefully managed caloric intakes and are bested suited for a ration balancer or vitamin and mineral supplement. On the other end of the barn are horses that still need considerable calories beyond their hay intake. These can include horses with Cushing’s that are underweight or even naturally hot performance horses. Horses with Cushing’s (either with or without insulin resistance as an added challenge) need a low starch diet due to hormone changes. Despite this, many still need more than hay or pasture to maintain their weight. Look for grain-free complete or senior feeds that contain moderate to high fat levels along with high fiber levels. What about performance horses? Although many performance horses need increased starch and glucose in their diet to complete the tasks asked of them, there are also many who are naturally more energetic without the boost of starch from cereal grains. If you have a hard-working horse that has plenty of “gas in the tank,” consider a high fat, lower NSC grain, like Woody’s Complete, that offers a cooler source of energy and calories.

Other horses that may benefit from a grain-free diet include horses with compromised digestive tracts. This includes ulcer-prone horses and rescue horses. Both of these groups benefit from a lower starch diet that will be easier on the digestive tract. Note—if you rescue a horse that is extremely underweight, please work with a PhD equine nutritionist or your veterinarian to develop a re-feeding plan.

What horses still need those carbohydrates?

Most working horses need glucose to perform athletic endeavors. This is particularly true for horses working at an anaerobic exercise level, for example, horses doing speed events or high-level jumping. Look for feeds that contain some cereal grains—products like our pelleted and textured performance feeds provide your horse with balanced energy from starch, fiber, and fat.

“My horse isn’t an Olympian, but I’ve been feeding them a high NSC feed with no issues. Is that a problem?” If it ain’t broke, don’t fix it. If the ration your horse eats works for him and works for you, keep on trucking.