Feeds and Supplements

The key to a good feed program is to start with the proper type of forage for the individual, then (if needed) pick the right concentrate or supplement.

Most horse owners try to provide the best diets for their horses, yet there's often a difference between what they think the animals need and what they actually need, and there are also some misunderstandings about how those needs can be met. With many good commercial feeds available and countless supplements on the shelves, it can be hard to know what's best for the horse.

Basic Feeds

Amy Gill, PhD, an equine nutritionist based in Lexington, Ky., says the foundation of a good diet is forage. Start with hay or pasture, then add grain concentrates and supplements only as needed. Most horses get by on little or no supplemental feed if they have good-quality forage. "All you need to provide is salt and fresh water," Gill says. "If forage is not ideal, add a supplement containing protein, vitamins, and minerals. It's a different story, however, if horses are stabled and don't have access to pasture; you've limited them to what you provide."

Pick the type of hay that best fits your horse. "Don't buy (a high-quality) alfalfa- orchardgrass mix for a fat, retired, insulin-resistant horse," says Gill. That type of hay is better suited for a young, growing horse or lactating mare. Find a lower-quality, lower-calorie hay for the fat, retired horse. He'll do better with hay that's safe to feed in larger amounts so he can occupy more time eating and be happier."

Protein supplements might be needed if hay is low in quality--if it stood too long in the field before being cut or if hot and dry conditions matured the crop too quickly. Grain or a commercial feed can be added if the horse needs more calories and nutrients than what he gets from the hay. For a hard-working horse, supplementing fat is useful if the horse needs more energy in the diet without the risk for laminitis or colic inherent in a high-grain ration.

Stephen Duren, PhD, an equine nutritionist and founder of Performance Horse Nutrition in Weiser, Idaho, says flax is popular as a fat supplement, and if it's whole flax (without the protein taken out), this acts as a protein supplement as well. He says some people get nervous about feeding too much protein, but this is generally not an issue. "Here in the West, where some regions grow alfalfa and relatively little grass hay, some horses eat nothing but alfalfa and do fine," explains Duren.


There are many different products for different types of horses, such as grain mixes for lactating mares or growing horses that need extra calories, as well as vitamins, minerals, and protein. These are less concentrated than some feeds because they are fed in higher volumes. Stephen Duren, PhD, an equine nutritionist and founder of Performance Horse Nutrition in Weiser, Idaho, says he also makes a mix he calls a "Jenny Craig" type of grain, which should be fed in very small amounts; it's very concentrated, to augment the vitamin and mineral portion of the diet. "It comes in pellet form, however, so you have the feeling you're feeding something, but it's not as high in calories."

Various feed mixes give horse owners options so they can fortify a diet without feeding more grain than a horse needs, from a caloric standpoint. Many companies and nutritionists realize that every horse doesn't need a large volume of grain, even when certain ingredients are needed to balance and fortify the diet.

"Figure out what's in your forage, determine what's missing, and then put together the proper caloric options in the feed mix for resolving those deficiencies," advises Duren.

--Heather Smith Thomas

A high-protein diet is not harmful unless a horse is working hard in the heat; then he might have trouble dissipating the extra heat generated in protein digestion. But for the average horse, extra protein is not a problem; he just breaks it down and excretes it. A high-protein diet is necessary, however, for a young, growing horse or lactating mare.

When using a national brand feed product formulated by equine nutritionists, and when feeding at the minimum recommended level, additional supplements are usually not needed. These complete feed mixes are formulated for the target animal's needs (young, growing horse, broodmare, hard-working horse, or older horse). "When fed as directed, the horse will get the proper amount of calcium, phosphorus, copper, zinc, etc.," says Duren.

Some people add vitamin or mineral supplements, hoof supplements, coat conditioners, joint supplements, or some other product. Most of these can be beneficial under certain conditions, as long as they are not overdone. Certain situations warrant using supplements or higher amounts of vitamins and minerals, but some of these (such as iron, iodine, selenium, and vitamins A, D, and E) leave little room for error regarding overdose. It's easy for a horse to get too much of a certain vitamin or mineral, for instance, if you are feeding several different supplements that all contain it. Overdoses of some (such as water-soluble B vitamins) are harmless because the body can excrete the excess, but others are not as easily removed and overdose is cumulative. Thus, it's important to know what the horse actually needs, and it's crucial to read labels and know what you are feeding.


"A hoof supplement usually contains biotin, zinc, and methionine, which are considered the three magic ingredients," says Duren. "Biotin is water-soluble. If you feed too much, it may cost you more money, but won't hurt the horse. Toxicity threshold for zinc is fairly high, so the amount of zinc in a hoof supplement probably won't hurt the horse. Methionine is an amino acid and, if not utilized, will just be run through the body's metabolism. Hoof supplements aren't always necessary, but are generally not dangerous. They are fed in small amounts and not meant to be the total dietary source."

Coat conditioners are generally fat supplements. The most popular ones contain more omega-3 fatty acids and less omega-6, striving for higher percentage of healthy fats.

"Oil in general helps the skin, and omega-3 fatty acids help with feet and hair coat, whereas the omega-6 type oils (soy, corn oil, and rice bran oils) merely add calories," says Gill. "Stick with flaxseed oil and products with a marine source of DHA (docosahexaenoic acid, found in algae, fish, and marine animal oils). These are healthiest and do the most good in the body regarding immune response, healthy membranes, fighting inflammation, etc."

Omega-3 fatty acids are found in green pasture plants, but not in a feed mix. "If a feed product lists this as an ingredient, it won't be good quality because these fatty acids must be protected from oxidation. They don't keep very well in a feed mix; they are highly volatile and have to be fresh," says Gill.

Duren reminds horse owners that fats might be great for the horse's coat, but they are also high in calories. "You may not only have a sleek horse, but also a fat horse," he says.

If your horse is an easy keeper, a fat supplement will not be beneficial. The extra calories are not an issue, however, if the horse is working. It's more a problem if he's not getting enough exercise to burn off the extra calories.


H ay grown in different geographic areas can have vastly different nutrient levels, especially in terms of minerals (and sometimes protein).

"In our area we are generally deficient in selenium," says Stephen Duren, PhD, an equine nutritionist and founder of Performance Horse Nutrition in Weiser, Idaho. "But in other aspects our forages are often better quality due to climate and better growing conditions (hay can often be put up at its optimum stage of maturity for a good protein level, and it is not as likely to be rained on). Horsemen don't have to feed as much grain as is common in equine diets in the East. In New England states, for instance, the average horse eats a lot more grain (and it probably is not necessary). If we aren't feeding textbook- recommended amounts of grain, we may need to select a more concentrated feed mix, with higher vitamin and mineral content, or supplement the horse if necessary. When I formulate feeds, I have to custom design them for the region. I look at forage analysis tests of forages in that area and design the grain mix to complement those."

--Heather Smith Thomas

Joint supplements are often given since these products are not found in regular grain diets. "Silicon, glucosamine, chondroitin, MSM, etc. can be part of a bone and joint program," says Gill.

Many horses in athletic careers are given joint supplements in an effort to keep them sound and prevent soreness/ stiffness.

"Ingredients and amounts in these supplements don't interfere with the rest of the diet," explains Duren, "so they are pretty safe, even though they are largely unregulated, and we're still not sure about efficacy and dose rates. Some have anti-inflammatory effects and can be helpful for older horses or working horses with a lot of stress on joints. But many people have the mis­conception that these products prevent injury--that they'll somehow make the horse tougher. In actuality, they can only help heal an injury.

"If an athletic horse has injury issues or a horse in training will be stressed and possibly suffer joint injury, I'd not hesitate to use joint supplements," continues Duren. "But they're a waste of money for a weanling or yearling. These supplements are most useful in horses that are old enough to have wear-and-tear on joints and doing daily work. There are studies being done on young horses with OCD to see if these ingredients will help healing, but this is a separate issue; you've already got damage and are trying to heal it."

Gill comments, "Regarding vitamins and minerals, if you're feeding a balanced diet--the right kind of hay for the horse and a supplement or concentrate designed for that horse--extra vitamins and minerals are not needed."

Hard-working athletes at peak performance might benefit from a well-rounded vitamin/mineral mix. They don't need it all the time, but in periods of hard work the horse might be helped by more B vitamins, vitamin E, and selenium.

Even though the horse's digestive tract makes B vitamins--with the help of intestinal microbes--in times of stress the horse might not have enough. Vitamin E and selenium are also useful because they are powerful antioxidants.

"There are also medical conditions in which a horse requires higher amounts of certain nutrients," says Gill. "Vitamin E and selenium are helpful with neurological problems. Magnesium and chromium may help the insulin-resistant horse. Biotin, zinc, and methionine are helpful for horses with weak hoof horn."

But unless a horse has a specific need, the horse owner should not feel compelled to add a supplement.

Take-Home Message

The key to a good feed program is to start with the proper type of forage for the individual, then pick the right concentrate or supplement (if needed) to balance the forage. "For an older horse or any horse with a problem, tweak the diet to help prevent or fix or manage the problem," says Gill. In those instances, work with an equine nutritionist to guide you in the right direction.

Shooting in the dark and indiscriminately adding supplements can sometimes be harmful. For instance, a horse with liver problems should never be fed high amounts of oil or protein since these must be processed in the liver, says Gill. Professional help in formulating the most helpful, healthy diet for a problem horse is the best way to go.

About the Author

Heather Smith Thomas

Heather Smith Thomas ranches with her husband near Salmon, Idaho, raising cattle and a few horses. She has a B.A. in English and history from University of Puget Sound (1966). She has raised and trained horses for 50 years, and has been writing freelance articles and books nearly that long, publishing 20 books and more than 9,000 articles for horse and livestock publications. Some of her books include Understanding Equine Hoof Care, The Horse Conformation Handbook, Care and Management of Horses, Storey's Guide to Raising Horses and Storey's Guide to Training Horses. Besides having her own blog, www.heathersmiththomas.blogspot.com, she writes a biweekly blog at http://insidestorey.blogspot.com that comes out on Tuesdays.

Stay on top of the most recent Horse Health news with FREE weekly newsletters from TheHorse.com. Learn More