What to Feed a Horse: Forage, Hay, Grain, and Ration Basics

Author: Elliott Garber, DVM

A horse should eat mostly forage, roughly 1.5 to 2.5 percent of its body weight in dry matter every day, with hay or pasture making up at least half the ration and always the base of it. Feed by weight, not by the scoop or coffee can, offer forage before any grain, keep clean water and loose salt available at all times, and adjust amounts based on the horse’s body condition rather than a fixed recipe. Most horses on good hay need only a ration balancer for vitamins and minerals, not bags of grain.

The forage-first principle

The horse is a hindgut fermenter built to graze almost continuously. In the wild it spends most of its waking hours eating small amounts of low-energy forage, and its digestive tract assumes a near-constant trickle of fiber. That biology is the single most important thing to understand about feeding a horse: forage is not the filler around the “real” feed, it is the real feed.

For an average healthy adult horse, plan the diet around eating roughly 1.5 to 2.5 percent of body weight in dry matter each day, with the Merck Veterinary Manual citing about 2 to 2.5 percent as a typical starting point and at least half of that coming from forage. For a 1,000 pound horse that works out to somewhere around 15 to 25 pounds of hay (dry matter) per day. Horses on all-hay diets will often voluntarily eat closer to 2.5 to 3 percent of their body weight, and the theoretical maximum intake is only about 3 to 3.5 percent. On the other end, forage should rarely drop below about 1 percent of body weight, a level reserved for horses in heavy work on high-concentrate diets, and the Merck manual notes that even restricted horses generally should not be fed less than about 1.25 percent of body weight in dry matter per day.

Getting the forage right, whether pasture, grass hay, or a legume like alfalfa, solves most of what a horse needs. Our horse hay guide goes deeper on hay types, quality, and storage, and the horse species page collects the rest of the care guides in one place.

Feed by weight, not by the scoop

One coffee can of pelleted feed and one coffee can of whole oats can differ substantially in weight, and two scoops of the same feed can vary depending on how packed they are. Feeding “a scoop” or “a can” is one of the most common ways horses get accidentally overfed or underfed. Both the Merck manual and university extension programs are explicit that concentrates should be measured by weight, not volume.

The practical fix is simple. Buy a cheap hanging or kitchen scale, weigh what your usual scoop actually holds of the feed you use, and write it on the scoop or bin lid. Do the same for hay: weigh a few typical flakes, because flake weight varies wildly between bales and cuttings. Once you know these numbers you can feed to a real target in pounds instead of guessing, and track intake over time when you adjust for a horse that is gaining or losing condition.

Why forage goes in before grain

The order you feed matters, not just the amounts. Putting hay in front of a horse before any grain slows the rate the stomach empties, blunts the spike in blood sugar and insulin after the meal, and slows how fast starch reaches the hindgut. When a large starch load arrives in the cecum and colon faster than it can be handled, it ferments rapidly, drops the pH, and shifts the microbial population in ways linked to colic and laminitis.

There is also the stomach itself. A horse’s stomach secretes acid continuously whether or not there is food in it, and forage, along with the chewing and saliva it triggers, buffers that acid. A horse standing for hours with an empty stomach has acid splashing against an unprotected upper stomach lining. That is a major reason equine gastric ulcer syndrome is so common, especially in performance horses and any horse fed a few large grain meals with long empty gaps between them.

So the working rules are: forage before concentrates, forage available for as much of the day as practical (a slow feeder or small-hole hay net helps stretch a hay ration without wasting it), and never let the horse stand empty for long stretches if you can avoid it.

The digestive risks of grain and infrequent meals

Grain is not poison, but it is easy to feed in a way that overwhelms the horse’s digestive system. Two things drive the risk: too much starch per meal, and too much of the total diet coming from concentrates.

Per meal, the Merck manual advises not offering more than about 0.5 percent of body weight in grain-based concentrate at a single feeding, which is about 5.5 pounds for a 500 kg (roughly 1,100 pound) horse. Larger starch loads outrun the small intestine’s ability to digest starch, so the excess spills into the hindgut and ferments. Across the whole diet, feeding more than about 50 percent of the ration as high-starch, high-sugar concentrate raises the risk of laminitis, colic, and gastric ulcers. If a horse genuinely needs a lot of concentrate to hold weight, the answer is usually to split it into more, smaller meals and to add calories from fat and highly digestible fiber (like beet pulp) rather than piling on more starch in one bucket.

Infrequent large meals are their own hazard. The horse evolved to trickle-feed, and dumping the day’s calories into one or two big grain meals produces exactly the blood-sugar swings, hindgut acidification, and empty-stomach acid exposure described above. Colic is a genuine emergency: if your horse is pawing, rolling, looking at its flank, off feed, or has few or no gut sounds, call your veterinarian right away rather than treating at home. Our horse colic guide covers the warning signs in detail, but nothing on a website replaces a vet’s hands-on exam and their judgment on medication.

When a ration balancer or complete feed beats plain grain

Here is the part that saves many owners money and worry: a horse on good-quality forage that is holding its weight fine usually does not need grain at all. What it needs is the vitamins, minerals, and quality protein that hay alone can fall short on. That is exactly what a ration balancer is for.

A ration balancer is a concentrated pellet fed in small amounts (often a pound or two a day, always follow the label rate for your horse’s weight). Because the feeding rate is so low, it delivers vitamins, minerals, and amino acids with negligible starch, sugar, and calories. For the easy keeper, the horse on plenty of pasture, or any horse that gets fat on air, a balancer fills the nutritional gaps without the digestive risk of a scoop of sweet feed. Grain-based concentrates should only be added on top of forage when a horse actually needs the extra calories, for example a hard keeper, a broodmare in late gestation or lactation, or a horse in heavy work.

A complete feed is a different tool. It is formulated to be fed as the entire diet, with the fiber built in, and it exists mainly for horses that can no longer chew or process long-stem hay well. That most often means senior horses with poor teeth, but also horses recovering from certain illnesses. Complete feeds are fed at much higher rates than a balancer (again, by weight, per the label and your vet’s guidance) and are usually split across several meals a day so the horse still gets a steady supply of fiber. Rutgers’ Equine Science Center has good detail on adapting the older horse’s ration, including soaking feed into a mash for horses that struggle to chew. If dental trouble is the reason you are reaching for a complete feed, get the teeth checked too; our horse dental guide explains why regular floating matters.

The short version: match the feed to the gap. Forage covers most needs, a balancer covers the micronutrient gap without calories, grain covers a real calorie deficit, and a complete feed steps in when the horse cannot eat hay properly. Your veterinarian or an equine nutritionist can help you pick, and any diet change should be made gradually over a week or two.

Fresh water and salt

Water is the nutrient horses need most and the one most easily overlooked. A mature horse needs roughly 8 to 12 gallons of clean water a day for maintenance, a figure that climbs steeply with heat, humidity, exercise, lactation, and how much dry hay the horse is eating, according to Oklahoma State University Extension. A rough field rule is at least one gallon per 100 pounds of body weight. Water should be clean and available at all times; a horse that stops drinking, especially in cold weather when trough water gets icy, is at real risk of impaction colic. In winter, taking the chill off the water encourages horses to keep drinking.

Salt is the one mineral horses will actively seek out, and most forage-based diets are short on sodium. Offer loose salt free choice, which horses use more reliably than a hard block, and expect a maintenance horse to need on the order of 1 to 2 tablespoons (roughly an ounce) a day, more when they sweat heavily in work or heat. Salt intake and water intake rise and fall together, so keeping salt available also supports good drinking. A plain white salt source covers sodium and chloride; a broader vitamin and mineral balance is better handled by a ration balancer or a forage-matched mineral supplement than by relying on a block to do everything.

Adjust by body condition, not a fixed recipe

No feeding chart knows your individual horse. The honest way to feed is to set a starting ration by body weight, then watch the horse and adjust. The standard tool is the Henneke body condition score, a 1 to 9 scale based on how much fat covers the neck, withers, ribs, loin, tailhead, and behind the shoulder. Most horses do well at a 5 (moderate), where you can feel the ribs easily but not see them. Learn to run your hands over those areas every couple of weeks, because your eye adjusts slowly and a horse that is quietly gaining or losing is easy to miss day to day. Our horse body condition guide walks through scoring, and the horse weight guide covers estimating weight with a weight tape when you do not have a livestock scale.

If a horse is gaining unwanted weight, cut concentrates first, then look hard at pasture access, since an easy keeper on rich grass may need a grazing muzzle or dry lot time; carrying too much fat raises laminitis risk. If a horse is losing weight, rule out teeth, parasites, and pain before simply adding grain, then add calories in the safest form: more or better forage, then fat and digestible fiber, then modest grain if still needed. Because these adjustments play out over weeks, writing them down is what separates guessing from managing.

That record-keeping is where a profile on Creatures helps. You can add your horse and then log its weight, body condition score, current ration, and any diet changes as records over time, so shifts in condition show up as a trend instead of a vague feeling. Keeping the feeding history alongside health and medical records also means the full picture is in one place when you talk to your vet, and you can set reminders for things like seasonal ration changes or the next dental check.

Frequently asked questions

How much hay should a horse eat per day?

Plan for roughly 1.5 to 2.5 percent of the horse’s body weight in dry matter per day, most or all of it as forage. For a 1,000 pound horse that is about 15 to 25 pounds of hay a day. Weigh your hay rather than counting flakes, since flake weight varies a lot between bales, and adjust up or down based on the horse’s body condition.

Does every horse need grain?

No. A horse on good forage that is holding a healthy weight usually needs only a ration balancer to cover vitamins and minerals, not grain. Grain-based concentrates are for horses with a real calorie gap, such as hard keepers, late-pregnant or lactating mares, or horses in heavy work.

Why is feeding order important?

Feeding forage before grain slows how fast the stomach empties, softens the post-meal blood sugar spike, and reduces the risk of starch overloading the hindgut. It also keeps buffering forage and saliva in the stomach, which helps protect against gastric ulcers.

How do I change a horse’s feed safely?

Make any change gradually over one to two weeks, replacing a small portion of the old feed with the new one each day. Sudden diet changes disrupt the hindgut microbes and are a well-known trigger for colic. When in doubt about the right diet for a specific horse, ask your veterinarian or an equine nutritionist.

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