Equine Nutrition 101: Guide to Horse Nutrients and Feeds

Knowing what to feed your horse is no simple task. For creatures that like such a simple diet, equine nutrition can seem complex and confusing.

But don’t worry, we’ve created this handy guide to equine nutrition that breaks down the six essential things that your horse needs in his diet and the two basic options you have when it comes to feeding a horse.

The Six Basic Nutrients Horses Need

Water

As with most living things, water is the single most important thing your horse consumes.

A horse will generally drink about 2 quarts of water for every pound of hay they consume. At 15-20 lbs. of hay per day for a 1,000 lb. horse, that’s 30-40 quarts of water every day. 

Horses in hard work, living in high-temperature areas, or mares who are pregnant or nursing will drink more - sometimes up to 3 times the usual amount. 

Horses often drink less water in the winter when it’s cold (a concern for horse owners in cold-weather environments - read our Guide to Winter Horse Care for tips on increasing water consumption during the winter).

Generally, a horse cannot go more than 3 days without water. But even an evening without a water bucket can cause a lot of health problems. 

Horses who are not getting enough water will eat less, appear dull and lethargic, and exhibit signs of dehydration like dry mucous membranes (nostrils and mouth), dry manure that is hard to pass, and increased capillary refill time. Dehydrated horses are also prone to colic. 

Carbohydrates

Carbohydrates are the main source of energy for your horse. There are two types of carbohydrates: structural (or non-soluble) carbohydrates and non-structural (or soluble) carbohydrates. 

Structural or non-soluble carbohydrates are fiber. In the case of the equine diet, this is grass or hay - the essential foundation of any balanced equine diet. Structural carbohydrates don’t just provide energy - because they’re digested in the horse’s hindgut (which encompasses the large intestine, cecum, large colon, and small colon) they provide the necessary bulk to keep the digestive system moving. 

Nonstructural or soluble carbohydrates are sugars or can be broken down into sugars. These are absorbed quickly in the stomach and small intestine and are either used immediately for energy or stored as fat. Foods like barley, oats, and corn (which has the highest amount) or sweet feed coated in molasses are all high in nonstructural carbohydrates. 

This type of carbohydrate can provide a burst of energy (this is where the term “feeling his oats” to describe someone with high energy comes from), but are dangerous in high amounts - they can cause colic, laminitis (an excruciatingly painful foot condition which can result in euthanasia), or obesity. 

Protein

Most of us know that protein helps build and maintain muscle, but it does a lot more than muscle up your mount. It’s essential for strong hoof growth, maintaining healthy skin, eyes, organ tissue, building bone mass in young horses, and keeping his coat looking shiny and healthy. 

Most healthy adult horses in normal work only need about 1.4 lbs of protein per day (based on an average weight of 1,100 lbs), which is easily provided by decent quality hay or forage.  

Alfalfa hay is a common source of protein and can contain as much as 25-30% protein. Most adult horses in light to moderate work only need about 8-10% protein though, so save the high-alfalfa hay for when he’s in very heavy work, or for a pregnant or nursing mare. 

Fats

Fats may get a bad reputation, but they’re another essential item your horse needs to be healthy (albeit in moderation). Fats are necessary to help the horse’s body absorb important fat-soluble vitamins like A, D, E, and K. 

Fats are also the best energy source available to a horse and can give a hard keeper (a horse who has a hard time gaining and maintaining a healthy weight) or a performance horse in heavy work an edge by packing a ton of calories in an easily digestible form. 

Fats are either added to a pre-mixed concentrate feed, or can be added in the form of an oil (often soybean oil, corn oil, or flax oil) to the top of the horse’s feed. 

Vitamins

Vitamins, in cooperation with minerals, perform a ton of roles in your horse’s body - everything from keeping the immune system functioning to growing bones and tissue and helping his body heal from illness or injury. 

The good news is that most of your horse’s vitamin needs can be met with fresh green forage or quality hay. Most pre-mixed feeds also contain an ample supply of the vitamins your horse needs, so unless a horse is under severe stress (like long-distance trailering, elite competition, or breeding), vitamin supplementation is generally not necessary. 

Horses who are confined to a stall night and day may benefit from a Vitamin D supplement since that’s generated by the sun. Horses on low-quality forage that’s been stored for a long time and is losing nutritional value may need a Vitamin E supplement. (But that doesn’t mean it’s a good idea to stall a horse day and night or feed poor quality hay). 

Horses under a ton of stress could benefit from a Vitamin C and B complex supplement to keep their immune system healthy while they’re under stress. 

It’s always best to consult your veterinarian or equine nutritionist before buying supplements to make sure your horse really needs a supplement, and exactly how much he needs. Supplements are expensive, so money spent consulting your vet now could save you hundreds on unnecessary supplements down the road.  

Minerals 

Your horse needs two types of minerals to keep his bones, brain, heart, and muscles working properly: macrominerals and trace minerals. 

Macrominerals like calcium, phosphorus, sodium, potassium, chloride, magnesium, and sulfur are needed daily, and in larger amounts. 

Macrominerals are found naturally in hay and grass, but the exact content varies so you’d be wise to get a nutritional analysis done before experimenting with supplementation. 

For example, alfalfa hay can have a particularly, sometimes dangerously, high ratio of calcium to phosphorus. Grass grown in acidic or clay-heavy soils may be low in magnesium, and low magnesium levels can cause everything from nervousness to muscle tremors in horses. 

Trace minerals like iron, manganese, copper, iodine, zinc, cobalt, fluoride, and selenium, are needed in smaller amounts. Again, these are typically naturally occurring in quality grass and hay.

Roughage like Lucerne, clover, and grass hay is typically high in trace minerals, and trace minerals can also be supplemented using a ration balancer, specially formulated salt lick, or loose supplement. 

Types of feed for horses 

Ok, so now you know exactly what your horse needs - the next question is how to get it into him. Horse feed is divided into two very broad categories - roughage (think hay and grass) and concentrates (like pelleted feeds and grain).

Roughage 

Roughage includes grass and hay, and less common hay products like hay cubes, sprouted fodder (the sprouts of grass or cereal grains like oats or barley, usually hydroponically grown in a thick mat), or silage (fermented hay fodder). 

Roughage is the foundation of a horse’s diet. The best, safest, and most natural diet for a horse is one that focuses on roughage, and only supplements with concentrates when necessary. In many cases, roughage is all a horse needs to live a healthy, happy life. 

Generally speaking, a horse needs to consume 2% of his body weight in roughage every day. This can come in the form of grass or hay. 

Types of Roughage 

Grass

Horses are designed to eat grass, so ideally grass will form the bulk of their diet.

To provide fresh grazing to support horses, you’ll need about 2-4 acres per horse. To prevent overgrazing (when a field is being eaten away faster than it can regrow), grazing should be managed so that part of the field is being rested while the other part is grazed. 

Hay

There are several different types of hay, and the exact species and mix of hay available to you may depend on your area of the country. But generally speaking, there are 2 main types of hay - grass hay and alfalfa

Alfalfa Hay

Thick, green, and very leafy, alfalfa is a high protein, high calorie, high calcium hay. It’s most commonly fed to horses in heavy work or breeding. Good alfalfa hay is deep green and leafy - most of the nutrients are in the leaves, not the stock. 

Grass Hay

This is the probably most common type of hay you’ll encounter. Fine, green, and sweet-smelling, it’s often a blend of orchardgrass, timothy, bermudagrass, and other native grasses.

Grass hay may also be mixed with alfalfa when grown to provide a little more calcium and calories, but if you have a horse that’s prone to laminitis or founder, you’ll want to opt for a pure grass hay, with little to no alfalfa.

Hay Cubes

For horses with dental issues like missing teeth or difficulty chewing, hay cubes—thoroughly soaked in water first to prevent colic and choking—are a great roughage supplement. 

Concentrates

Concentrates are any food in your horse’s diet that isn’t roughage, and generally the least natural thing he’ll eat. While safe to feed, be aware that concentrates are not foods that horses were designed to eat, and the likelihood of colic is greatly increased in stalled horses that are fed concentrates. 

That said, many horses have nutritional needs that can’t be satisfied by roughage alone, so concentrates are needed to round out his diet. 

Types of Concentrates

There’s a dizzying array of concentrates available, from an old-fashioned bag of oats to specially formulated mixed feeds for every type of horse in every type of work. 

Generally, horse owners can choose between a ration balancer to round out needs not met by roughage alone; a mixed feed like pellets, pre-mixed grain ration, or a mix of both, or traditional whole grains. Let’s take a look at each. 

Ration Balancer

A ration balancer is a form of concentrate, but not all concentrates are ration balancers. A ration balancer is a nutritionally-balanced pellet designed to balance out the horse’s roughage ration by providing vitamins and nutrients that may not be provided by hay. 

For horses who have nutritional needs that cannot be met by hay alone, a ration balancer incorporated into a hay diet is generally preferable and much safer to feed than a high grain diet. 

Grains

While many associate grains like oats or corn with horses, they’re not as commonly fed as they once were. Most stables, boarding facilities, and horse owners use pre-mixed feeds, which come nutritionally-balanced for horses with various needs. 

Unless you really know what you’re doing, meeting all of your horse’s nutritional needs by mixing grains and supplements at home from scratch is actually pretty unlikely. You, and your horse, are in most cases better off with a pre-mixed feed. 

Oats

Oats contain about 13% fiber, making them the safest grain to feed and a better choice for horses who are prone to colic or founder. 

Corn

Corn is an incredibly high-energy feed and should only be fed sparingly and when absolutely necessary to satisfy a horse with high energy needs, like racehorses. Choose corn that has been cracked or steamed and rolled - unprocessed corn is not easily digested. 

Soybean Meal

Made of pulverized soybeans, soybean meal is a high protein (44-48%) grain added to many concentrated mixes. 

Beet Pulp

While not technically a grain, this cast-off of the sugar manufacturing process is a great source of fiber to increase the digestibility of grain rations and is a good source of energy. 

Mixed or Complete Feed

Most horses who are eating concentrates are on a mixed feed of some kind. Mixed feeds, as the name implies, are special blends of grains, ration-balancing vitamins and nutrients, and also pelleted or extruded feeds. 

Mixed feeds may also contain ingredients like molasses (to sweeten the feed and make it “stickier”, and less dusty), or hay chaff to add fiber and increase digestibility. 

Mixed or complete feeds are the most popular type of feed, for good reason. They’re easy - formulated for specific needs, like growing horses, maintenance, high performance, broodmare, or seniors, you don’t need to buy additional supplements or additives to get your horse the nutrition he needs. 

Mixed foods are designed to be fed as a complete feed, meaning it provides all of the nutritional requirements of the type of horse it was designed for. Keep this in mind when buying hay - if he’s already getting a lot of energy or protein from his grain ration, you’ll probably want to opt for a later cut grass hay to avoid overdoing it. 

“So, what should I feed my horse?”

Like most things with horses, the correct answer is “it depends”. 

Most horses in light work can do fine on grass if there’s enough grazing available, with quality hay to round out the times when grass is sparse. Horses who are in training, asked to compete, or otherwise in a situation where roughage alone isn’t enough are candidates for concentrates.

No matter what you feed, remember to always keep fresh, clean water available, focus on fiber, and make sure he’s getting enough carbs, proteins, fats, vitamins, and minerals to keep his body in tip-top shape.

Share your story: What do you feed your horse, and why? Let us know in the comments below!