The Pros and Cons of Feeding Horses Oats

Oats for horses are the oldest cereal grain in the British equestrian feed shed, and one of the most misunderstood. They have been part of horse diets for centuries because they are widely available, relatively affordable and easier on the equine digestive tract than maize or barley. But oats are also energy-dense, calcium-poor and entirely wrong for some horses. This guide weighs the pros and cons, compares oats with other cereals, breaks down the four common processing forms, and gives realistic UK feeding rates so you can decide whether oats belong in your horse’s bucket.

Oats for Horses: The Quick Answer

Oats are an excellent “quick-release” energy source for horses in moderate to hard work — eventers, hunters, racehorses and competition show jumpers. They are not appropriate for laminitic, EMS, Cushing’s, easy-keeper or retired horses. The British feed industry generally recommends oats only for horses earning their keep through real, daily exercise. Whatever the workload, oats sit on top of a forage-first diet — they are a supplement to grass and hay, never a replacement for them.

Nutritional Profile: What Is Actually in Oats?

Per kilogram of dry matter, whole UK feed-grade oats typically provide:

• Digestible energy: 11–12 MJ DE/kg
• Crude protein: 11–13%
• Starch: 40–50% (the main energy source)
• Crude fibre: 10–12% — the highest of any cereal grain
• Oil: 4–5%
• Calcium: 0.07% (very low)
• Phosphorus: 0.34% (high) — an inverted Ca:P ratio of roughly 1:5

That inverted calcium-to-phosphorus ratio is the single most important nutritional fact about oats. Horses need a Ca:P ratio of at least 1.5:1. Feeding oats without correcting this — usually with alfalfa (lucerne) chop, sugar beet or a balancer — pulls calcium from bone over time and is one of the classic causes of nutritional secondary hyperparathyroidism (“big head” in growing stock). For the full picture on balancing a cereal-based ration, read our guide to horse feeding and nutrition.

Oats vs Barley, Maize and Other Cereals

The reason oats earned their place in the feed room comes down to where their starch is digested. Starch that is broken down in the small intestine is used safely as glucose. Starch that escapes to the hindgut ferments, drops the gut pH and raises the risk of colic and laminitis. Oats win on that measure:

• Oats — roughly 11–12 MJ DE/kg, 40–50% starch, but 80%+ pre-caecal (small-intestine) starch digestibility. The safest common cereal for the hindgut, and the highest in fibre
• Barley — higher energy at around 13 MJ DE/kg and around 55% starch, but only ~20% is digested pre-caecally when fed whole. Barley must be cooked, micronised or rolled to be fed safely, and even then carries more hindgut risk than oats
• Maize (corn) — the most energy-dense at around 14 MJ DE/kg and 65–70% starch, yet only ~30% pre-caecal digestibility raw. It is the “hottest” cereal kilo-for-kilo and the easiest to over-feed

In plain terms: oats give you fewer calories per scoop than barley or maize, but they are far more forgiving of the human error that causes most feed-related colics. That trade-off — less concentrated energy in exchange for a wider safety margin — is exactly why generations of UK yards reached for oats first. Research bodies such as Kentucky Equine Research recommend adding a small, measured amount of oats as a safe way to lift energy in a horse lacking get-up-and-go.

The Pros of Feeding Horses Oats

• High pre-caecal starch digestibility — oat starch is digested largely in the small intestine, before reaching the hindgut. Compared to maize (around 30% pre-caecal) or barley (around 20%), oats reach 80%+ pre-caecal digestibility. That dramatically reduces the colic and laminitis risk that comes with starch fermenting in the caecum
• Familiar, predictable energy — experienced UK trainers and grooms have generations of feel for how a horse responds to oats. The behaviour change is consistent and the energy is fast-release for jumping or fast work
• Palatability — horses almost universally take to oats. Useful for fussy feeders, post-illness rebuilds and underweight horses who refuse other concentrates
• Chewing and saliva — whole and lightly processed oats require thorough chewing, which produces saliva to buffer stomach acid and supports dental and digestive health
• Husk and fibre — the natural husk slows the rate of consumption and reduces the risk of choke compared to a finer-ground feed
• British, cheap and traceable — UK-grown feed oats from suppliers like Baileys Best British Oats, Allen & Page Rolled Oats or GWF Tiger Oats cost £14–£19 per 20kg sack, well below most balanced mixes

The Cons of Feeding Horses Oats

• Excitable behaviour — the “sparkle” of oats is real. Sharp, sensitive horses or ponies under-worked relative to their feed intake become spooky, on-edge or unsafe. The phrase “feeling his oats” came from somewhere
• Calcium-deficient — must always be balanced with alfalfa, sugar beet or a vitamin/mineral balancer. Oats fed alone are not a complete feed
• High starch and sugar (NSC) — total non-structural carbohydrate of around 50% rules them out for any horse with EMS, PPID/Cushing’s, a history of laminitis, gastric ulcers, polysaccharide storage myopathy (PSSM) or recurrent tying-up (azoturia)
• Poor for easy keepers — native ponies, cobs and warmblood crosses on good grazing rarely need any cereal. Adding oats often produces weight gain rather than performance
• Bulky to store — the same scoop weight delivers fewer nutrients than a compound feed, so feed-room storage and transport costs add up
• Variable quality — cheap feed-grade oats can be dusty (dust contributes to respiratory problems such as equine asthma in stabled horses) and occasionally affected by mould toxins

Whole, Rolled, Bruised or Micronised: Which Form Is Best?

Processing matters because the oat husk is tough and the inner kernel is the digestible part. The four common forms in UK feed shops are:

• Whole oats — the cheapest option. Adult horses with good teeth digest whole oats reasonably well (60–70% small-intestinal digestibility). Senior horses and youngstock with developing molars do significantly worse on whole oats — you will see undigested oats in the manure
• Rolled oats — the husk is partly cracked but intact, exposing the kernel. Digestibility lifts to 70–80%. Best general-purpose form. Allen & Page Rolled Oats and Equi-Box Rolled Oats are widely sold in 20kg sacks
• Bruised or crimped oats — lightly crushed by rollers; similar performance to rolled but stays fresher in storage
• Micronised or steam-flaked oats — cooked under infrared heat or steam, gelatinising the starch and pushing pre-caecal digestibility above 90%. Most expensive but the lowest hindgut-fermentation risk — the form Forageplus, Highclere Castle Horse Feeds and Baileys all favour for performance horses

Once oats are bruised or rolled, oxidation begins. Use within 4–6 weeks of milling and store in a cool, dry, vermin-proof bin. If the smell turns “off” or rancid, discard the lot.

Horse Oats vs Human Porridge Oats

One of the most common questions on UK livery yards is whether the porridge oats from the supermarket are the same thing as feed-grade oats. Biologically, plain rolled porridge oats are the same grain, and a handful will not harm a healthy horse. The differences are practical rather than nutritional:

• Cost — supermarket porridge oats work out at several times the price per kilogram of feed-grade oats bought in a 20kg sack from an equestrian merchant. For anything beyond a token handful it is uneconomical
• Form — human porridge oats are rolled and dehusked, so they lack the fibre-rich husk that slows eating and supports gut health. They are absorbed faster, which can make them slightly “hotter” gram-for-gram
• Additives — never feed flavoured, sweetened, “golden syrup” or instant porridge varieties. The added sugar is unnecessary at best and a laminitis risk at worst. Stick to plain rolled oats only

The verdict: plain porridge oats are a safe occasional treat or a way to tempt a fussy or recovering horse, but feed-grade rolled or bruised oats are the sensible choice for any regular feeding.

How Much Oats Should You Feed?

The two universal rules for cereal feeding apply to oats:

• Never exceed 2g of starch per kg of bodyweight per meal (about 0.5kg of oats for a 500kg horse)
• Feed at least 1.5–2% of bodyweight per day in forage first — cereal sits on top of forage, not in place of it

Realistic daily ranges for a 500kg horse, split across two or three feeds:

• Light hack/dressage (1 hr easy, 5 days/wk): 0–0.5kg oats/day
• Riding-club/show jumping (1 hr daily, schooling + competing): 0.5–1.5kg oats/day
• Eventer/hunting (2 hrs/day mixed work): 1.5–2.5kg oats/day
• Racing/3-day eventing in season: 2.5–4kg oats/day, split into three feeds

Always pair oats with alfalfa (lucerne) chop or a calcium-rich balancer to correct the Ca:P ratio. A typical UK ration: 0.5kg rolled oats + 0.3kg alfalfa chop + a slice of soaked sugar beet + a handful of vitamin/mineral balancer. Ponies need proportionally far less — see our guide to feeding a pony before adding any cereal to a native’s bucket.

How to Prepare and Soak Oats

Most horses are fed oats dry, mixed straight into a chaff-based feed. Preparation is mainly about safety and palatability rather than digestion:

• Dry feeding — perfectly fine for rolled, bruised or micronised oats fed to a horse with sound teeth. Mix into a damp chaff so the oats cannot be bolted or sifted out and left
• Soaking — soaking oats in clean water for 15–30 minutes softens them for senior horses, poor doers and any horse prone to choke or with worn molars. It also reduces dust. Do not leave oats soaking for hours in warm weather, as they ferment and sour quickly
• Never boil or cook raw oats at home — there is no benefit over commercial micronising and a real scald risk. If you want gelatinised starch, buy micronised oats
• Damping down — even a splash of water over a dry feed cuts dust and slows a greedy eater, lowering choke risk

Feeding Oats for Weight Gain and Condition

Oats can help a genuinely underweight, hard-working horse hold condition, but they are not the first tool to reach for. Because the energy is fast-release, piling oats into a thin horse often adds fizz before it adds weight. A safer route to condition is more forage, oil and high-fibre “slow” calories, with oats added only if the horse is also in real work. If your horse is struggling to gain weight, work through the underlying causes first — our nutrition guide on feeding horses for weight gain covers the forage-led approach in detail. Always rule out dental problems, a worm burden, gastric ulcers or pain before assuming the horse simply needs more cereal.

Feeding Oats in Winter

There is a persistent myth that horses need extra oats to “keep warm” in winter. In reality, the heat a horse generates from digestion comes overwhelmingly from fermenting fibre in the hindgut — not from cereal starch. Feeding more forage, ideally good haylage or hay, is the correct way to help a horse stay warm through a cold snap. Oats may have a place in winter for a horse in hard work whose energy demand genuinely rises, but a stabled, under-worked horse on extra oats and a smart rug is a recipe for a sharp, over-fresh ride. Match the rug to the conditions and the workload to the feed, not the other way round.

Which Horses Should NOT Be Fed Oats?

Oats are inappropriate for:

• Any horse with a history of laminitis, EMS or PPID (Cushing’s)
• Horses prone to gastric ulcers or with confirmed EGUS — cereal starch worsens squamous ulceration
• Horses with PSSM type 1 or 2, recurrent azoturia or other myopathies — switch to a high-fat, low-starch feed
• Native ponies on grass — usually need only forage and a balancer
• Retired or very lightly worked horses — the calorie load is wrong for the workload
• Underweight horses where the cause is dental, parasitic or pain-related — treat the cause first

If any of these apply, ask your vet or a qualified equine nutritionist (e.g. an SQP qualified through BETA) for a tailored ration. The British Equestrian Trade Association (BETA) NOPS scheme guarantees competition feeds are free from prohibited substances, and resources such as Spillers and Horse & Hound’s feeding features are useful further reading for performance diets.

UK Horse Oats & Feed Brands Compared

Quick reference for what UK riders actually find on the merchant’s shelf:

• Baileys Best British Oats — lightly bruised, UK-grown, £14–£15/20kg. Targeted at moderate-to-hard work
• Allen & Page Rolled Oats — rolled, traditional £15/20kg sack. Well-established workhorse
• GWF Tiger Oats — 13 MJ/kg with added vitamin/mineral pellet, £18–£19/20kg. Closer to a complete feed
• Forageplus Micronised Oats — flaked and micronised, £13.49/sack, performance-orientated
• Dodson & Horrell Oat Balancer — a low-feed-rate balancer specifically formulated to correct the calcium and trace minerals when oats are the main grain

How to Introduce Oats Safely

The hindgut microbiome takes seven to ten days to adjust to any feed change. Introduce oats gradually:

1. Start with 100–200g/day for two days
2. Increase by 200g every two days until target rate is reached
3. Split into multiple meals if total daily oats exceed 1kg — never feed more than ~0.5kg per meal
4. Introduce alfalfa or balancer at the same time, not later
5. Watch for loose droppings, behaviour change or any sign of laminitis (bounding digital pulse, shifting weight) — back off immediately if seen

Pair this guide with our companion articles on horse feeding 101, how to make hay and the horse rug temperature guide for a full feeding-and-management picture.

Frequently Asked Questions

Are oats good for horses?

Oats are an excellent feed for horses in moderate-to-hard work because their starch is digested mostly in the small intestine, reducing colic and laminitis risk. They are not appropriate for laminitic, EMS, PSSM, ulcer-prone or easy-keeper horses, and they must always be balanced with calcium from alfalfa or a balancer.

How much oats should I give my horse a day?

For a 500kg horse: 0–0.5kg/day for light hack work, 0.5–1.5kg/day for riding club and showjumping, 1.5–2.5kg/day for eventing or hunting, and 2.5–4kg/day for racing. Never feed more than 0.5kg per meal (2g starch per kg bodyweight) and split larger amounts across two or three feeds.

Can horses eat oats from the grocery store?

Yes, plain rolled porridge oats from a supermarket are biologically the same grain as feed-grade rolled oats and will not harm a healthy horse. The cost per kilogram is far higher than buying feed-grade oats from an equestrian merchant, so it is rarely practical beyond a handful. Avoid flavoured, sweetened or instant porridge oats — the added sugar is unnecessary and can be a laminitis risk.

Are whole oats or rolled oats better for horses?

Rolled, bruised or micronised oats are better than whole oats for most horses because the husk is partially broken, raising digestibility from 60–70% to 80–90%. Whole oats are acceptable for adult horses with good teeth but underperform with seniors and youngstock, where you will see undigested kernels in droppings.

Can a horse colic on oats?

Yes — any cereal can trigger colic if over-fed. The risk comes from too much starch reaching the hindgut, where it ferments and disrupts the gut. Oats are the safest common cereal because most of their starch is digested earlier, but feeding more than about 0.5kg per meal, making sudden changes, or feeding cereal without enough forage can still cause colic. Introduce oats gradually and keep meals small.

Why are oats considered a “heating” feed for horses?

“Heating” is a behavioural term, not a physiological one. Oats deliver a fast hit of small-intestine glucose that can produce excitable, sharp behaviour in some horses, especially those whose work load is too low for the calories provided. The digestive process itself does not raise body temperature — fibre fermentation does far more to keep a horse warm than cereal.

Last updated: June 2026 by the Bit & Bridle editorial team.