What Can Horses Eat? The Complete Feeding Guide Every Owner Needs (Vet-Approved)

Why Getting This Wrong Can Cost You Your Horse’s Life

What can horses eat? It’s a question every new owner asks, and I still remember the first colic call I ever fielded as a young barn manager that taught me just how serious the answer really is. A boarder had “treated” her gelding to a full bucket of fresh-cut grass clippings from her lawnmower, thinking she was doing him a favor.

By midnight, he was rolling in his stall and sweating through his blanket. We were lucky. The vet arrived in time, and he pulled through after a rough 48 hours.

That night taught me something every horse owner eventually learns the hard way, or, better, learns from someone else’s mistake: horses have one of the most unforgiving digestive systems in the animal kingdom. What seems like a harmless snack can trigger colic, laminitis, or worse, in a matter of hours.

This guide breaks down exactly what can horses eat, how much, and why their gut biology makes feeding them so different from feeding a dog or a cow. I have spent years around barns, from backyard hobby farms to competition yards, and I am folding that hands-on experience into the science below so you know precisely what can horses eat safely and what to avoid.

Understanding the Horse’s Digestive System First

Before you fill a feed bucket, it helps to understand what you are actually working with. Horses are non-ruminant herbivores, sometimes called “hindgut fermenters.” They have a single, relatively small stomach (holding roughly 2 to 4 gallons in an average adult), unlike a cow’s four-chambered system.

Because of this, horses cannot regurgitate or “chew their cud.” Food moves one direction only, and their stomach is designed for a slow, near-constant trickle of forage, not two or three large meals.

Fiber digestion happens later, in the cecum and large colon, where billions of microbes ferment plant cellulose into usable energy. According to <a href=”https://en.wikipedia.org/wiki/Equine_nutrition” target=”_blank” rel=”noopener”>documented equine physiology research</a>, this hindgut fermentation process is precisely why sudden diet changes are so dangerous. A rapid shift in feed disrupts the microbial population, and that imbalance is one of the leading triggers of colic and laminitis.

Key takeaway: any change to a horse’s diet, whether new hay, a different grain, or a lush spring pasture, should happen gradually over 7 to 14 days.

The Foundation: Forage Should Be 100% of a Horse’s Instinct

If you remember one rule from this entire article, make it this one: forage comes first.

How Much Grass or Hay Does a Horse Actually Need?

Research compiled by the University of Nebraska-Lincoln Extension recommends that a mature horse at maintenance consume between 1.5% and 2.0% of its body weight in forage daily. For a 1,000-pound horse, that works out to 15 to 20 pounds of hay or pasture grass every day, as the “G1781 Feeding Management guide” outlines in detail.

The University of Minnesota Extension backs this up with a similarly practical rule: most idle adult horses should eat about 2% of their body weight in hay to meet nearly all of their nutrient needs from forage alone, without needing added grain.

Here is a simple way to estimate your own horse’s forage needs:

• Weigh your horse (a livestock scale is ideal, but a weight tape or the girth/length formula works in a pinch).
• Multiply body weight by 0.015 to 0.02 to get the pounds of forage needed per day.
• Split that total into at least 3 to 4 feedings, or better yet, use a slow feeder net so the horse can graze near-continuously.

In my own experience managing a small boarding barn, the horses who had 24/7 access to a slow-feed hay net had noticeably fewer ulcer flare-ups and stall-weaving habits than the ones fed just twice a day. An empty stomach for even four hours can start exposing the unprotected upper stomach lining to acid, which is a major contributor to gastric ulcers.

Grass vs. Hay: What’s the Difference?

Concentrates: When Grain Actually Belongs in the Bucket

Grain, or “concentrate feed,” is not automatically necessary. A moderate-activity adult horse getting quality forage often does not need it at all.

Concentrates become useful for:

• Growing foals and yearlings (contributing up to 50% of the ration during the first two to three years, per equine nutrition fact sheets from USU Extension)
• Lactating or late-gestation mares
• Hard-working performance and competition horses
• Senior horses who struggle to chew or absorb enough nutrition from forage alone

Common concentrate ingredients include oats, corn, barley, wheat, soybean meal, and beet pulp, often pelleted with molasses added for palatability. The golden rule with grain is portion control. Because concentrates digest quickly in the small intestine, overfeeding them floods the hindgut with starch, which ferments abnormally and can trigger colic or laminitis. Most feeding guides recommend keeping any single grain meal under roughly 5 pounds (about 2.3 kg) for an average-sized horse, split across two or three feedings rather than one large scoop.

Safe Treats: The Fun Part (Done Right)

Treats build trust and make handling easier, especially with young or nervous horses. From my own trail-riding days, a pocketful of the right treats turned a head-shy gelding into one of the easiest horses I ever loaded into a trailer, simply through consistent, calm positive reinforcement.

Generally safe in moderation:

• Carrots (sliced lengthwise to reduce choke risk)
• Apples (core and seeds removed)
• Bananas (peel included, in small amounts)
• Watermelon (rind and flesh)
• Celery
• Sugar snap peas
• Commercial horse treats or peppermints (in moderation)
• Plain, unsalted hay cubes or beet pulp shreds as a “treat base”

Feed treats with these guardrails:

• No more than 10 to 15% of the daily diet should come from anything outside hay/grain/balanced feed.
• Always cut round fruits and vegetables lengthwise, never into round coins, to prevent choke.
• Introduce any new treat in a small amount first to rule out sensitivity.

Foods and Plants That Are Genuinely Dangerous

This is the section that matters most, and it is worth reading slowly.

Dr. Leslie Easterwood, a clinical assistant professor at the <a href=”https://vetmed.tamu.edu/news/pet-talk/keeping-horses-safe-from-toxic-plants” target=”_blank” rel=”noopener”>Texas A&M College of Veterinary Medicine & Biomedical Sciences</a>, notes that horses generally avoid toxic plants when good forage is available, since most poisonous plants taste bitter or unappealing. The real danger comes when pasture is overgrazed, or when clippings, cuttings, or ornamental trimmings are tossed where a horse can reach them.

Never Feed Your Horse:

• Chocolate or anything containing caffeine or theobromine
• Avocado (leaves, bark, seeds, and skin can cause swelling of the lips, mouth, and throat, and has been linked to colic, according to compiled toxic plant data from University of Georgia Extension)
• Onions, garlic, chives, and shallots
• Bread, pastries, or sugary/starchy human snacks in any real quantity
• Lawn clippings (they ferment rapidly and can cause severe, fast-onset colic, which is exactly what happened in the story that opened this article)
• Moldy or dusty hay/grain of any kind
• Persimmon fruit (skin, pulp, and seeds have been linked to stomach ulcers and even rupture)
• Wilted red maple, black walnut, oak, or wild cherry leaves and bark

Toxic Plants to Remove From Pastures and Fence Lines

According to toxic plant compilations from University of Georgia Extension and the Cornell University Poisonous Plants database, high-risk species include:

• Oleander
• Hemlock
• Bracken fern
• Johnsongrass (especially when stressed or wilted, due to cyanide compound risk)
• Locoweed
• Yew (Taxus species, extremely toxic even in small amounts)
• Foxglove
• Black locust

Practical tip from the field: walk your pasture fence lines every spring and after every storm. Downed tree limbs from black walnut, wild cherry, or red maple are one of the most common, and most preventable, causes of accidental poisoning.

Feeding Formula: How to Calculate Your Horse’s Daily Ration

For readers who want the actual math, here is the biomechanical formula equine nutritionists use, based on body weight:

Total daily intake (lbs) = Body weight (lbs) × 0.015 to 0.025

Then split between forage and concentrate depending on workload:

(Data adapted from University of Nebraska-Lincoln Extension’s G1781 feeding guide.)

If you do not have access to a livestock scale, you can estimate body weight using the heart girth and body length formula:

Weight (lbs) = (Heart Girth in inches)² × Body Length in inches ÷ 330

Measure heart girth around the horse’s circumference just behind the withers, and body length from the point of the shoulder to the point of the buttock.

Breed-Specific Feeding Notes

Not every horse processes feed the same way, and breed matters more than most new owners expect.

• Easy keepers (ponies, Quarter Horses, Morgans, many draft breeds): These breeds evolved to survive on sparse forage and are highly prone to obesity and laminitis on rich pasture. Restricting grazing time with a grazing muzzle, and avoiding alfalfa or high-sugar grain, is often necessary.
• Thoroughbreds and warmbloods in competition work: Higher metabolic demands mean these breeds often need added fat sources (like stabilized oils, which can be fed up to 6 to 12% of total ration energy) rather than simply more starch, per University of Georgia Extension fat-feeding data.
• Arabians: Generally efficient metabolizers; many do well on forage-only diets even in moderate work, and are prone to weight gain if overfed concentrates.
• Senior horses of any breed: Dental wear reduces chewing efficiency. Soaked hay cubes, beet pulp, or a senior feed formulated for easier digestion often become necessary once a horse struggles to maintain weight on hay alone.

Breed and discipline organizations, including the <a href=”https://feif.org/” target=”_blank” rel=”noopener”>International Federation of Icelandic Horse Associations</a> and national breed societies, publish their own management guidance for owners, and it is worth checking your specific breed’s recommendations if you are managing a metabolic condition like Equine Metabolic Syndrome or PPID.

Practical Feeding Tips for Every Owner

• Introduce new feed slowly. Blend 25% new feed with 75% old feed, shifting the ratio gradually over a full week.
• Never feed immediately before or after intense exercise. Most guidance recommends withholding a large grain meal for about 3 to 4 hours before hard work.
• Provide free access to clean water. An adult horse drinks 5 to 15 gallons daily, and dehydration dramatically raises colic risk, especially when hay intake is high.
• Offer a salt block or loose salt year-round, and increase it in hot weather or during heavy sweating.
• Watch body condition, not just the scale. Learn to check ribs, topline, and crest by hand every few weeks.
• Keep a hay analysis on hand if possible. A basic forage test tells you the actual sugar, protein, and mineral content, rather than guessing.

Final Thoughts

Feeding a horse well is not complicated once you understand the underlying biology: forage first, grain only as needed, treats in true moderation, and a sharp eye on anything that could be toxic. The horses I have cared for that thrived the longest were never the ones on the fanciest supplements. They were the ones with consistent turnout, clean forage, and an owner who paid attention to the small details.

When in doubt about a specific plant, supplement, or medical condition, your veterinarian and a qualified equine nutritionist remain your best resource. This article is educational and does not replace individualized veterinary guidance.

Also Read: Equine Healthy Food: The Ultimate Guide to What Your Horse Should (and Should Not) Eat

FAQs

1. What can horses eat besides hay and grass?

Beyond forage, horses can safely eat commercial concentrate feeds, beet pulp, carrots, apples, bananas, and small amounts of other approved treats. Forage should still make up the bulk of the diet, ideally 1.5 to 2% of body weight daily.

2. Can horses eat bread?

Horses can technically eat small amounts of plain bread without immediate harm, but it offers little nutritional value and is high in refined starch. Regularly feeding bread can contribute to digestive upset, so it is best avoided as a habit.

3. What human foods are toxic to horses?

Chocolate, avocado, onions, garlic, and anything high in caffeine or theobromine are toxic to horses. Lawn clippings and moldy feed of any kind are also dangerous and can trigger rapid-onset colic.

4. How much hay should a 1,000 pound horse eat per day?

A 1,000 pound horse at maintenance level typically needs 15 to 20 pounds of hay daily, based on the 1.5 to 2% of body weight guideline used by university extension programs.

5. Can horses eat carrots and apples every day?

Yes, in moderation. Carrots and apples are generally safe daily treats when cut lengthwise to prevent choking, but they should stay within roughly 10 to 15% of the horse’s total daily diet to avoid excess sugar intake.

Sources and Official References

Rutgers Equine Science Center / Equine Nutrition overview: https://en.wikipedia.org/wiki/Equine_nutrition

University of Nebraska-Lincoln Extension, “Basics of Feeding Horses: Feeding Management” (G1781): https://extensionpubs.unl.edu/publication/g1781/2007/html/view

University of Minnesota Extension, “Using Hay in Horse Diets”: https://extension.umn.edu/horse-nutrition/hay-horse-diets

Texas A&M College of Veterinary Medicine & Biomedical Sciences, “Keeping Horses Safe from Toxic Plants”: https://vetmed.tamu.edu/news/pet-talk/keeping-horses-safe-from-toxic-plants

University of Georgia Extension, “Plants Reported to be Toxic When Ingested by Horses”: https://site.extension.uga.edu/bartow/plants-reported-to-be-toxic-when-ingested-by-horses

Disclaimer: This article is intended for general educational and informational purposes only and does not constitute professional veterinary or nutritional advice. Every horse’s dietary needs vary based on age, breed, health status, workload, and medical history. Always consult a licensed veterinarian or a qualified equine nutritionist before making changes to your horse’s diet, introducing new feeds or supplements, or addressing a suspected toxic ingestion. If you believe your horse has eaten something poisonous or is showing signs of colic, laminitis, or distress, contact your veterinarian or an equine emergency clinic immediately.