What if your horse needed
far less concentrate
than you think?
Horse nutrition isn't about kilograms of feed. It's about nutrients, and where they come from. Scroll to see feeding the way a nutritionist sees it.
Every horse needs the same things
Not products. Nutrients. Whatever you feed, hay, concentrate, balancer or supplement, your horse's body is looking for these nine building blocks. Tap a card to see what each one does.
Our reference horse: 550 kg, light work
Requirements scale with bodyweight, so every figure on this page is anchored to the same horse. Multiply the middle column by your own horse’s weight and you have its numbers. We feed this reference horse 11 kg of hay a day as fed — 2% of its bodyweight as fed, about 1.8% in dry matter — the same ratio used throughout this page.
| Needs per day | Per kg bodyweight | 550 kg horse | From 11 kg of our Meadow |
|---|---|---|---|
| Forage (dry matter) | 15–25 g | 8.25–13.75 kg | 9.7 kgcomfortably in range |
| Energy | 0.04 Mcal | 22 Mcal | 18.0 Mcal82%, more hay closes it |
| Protein | 1.4 g | 770 g | 784 gcovered by forage alone |
| Lysine | 0.06 g | ~33 g | not measuredno lab figure, so no claim |
| Calcium | 0.04 g | 22 g | 37 gCa:P 1.9:1, inside the norm |
| Phosphorus | 0.028 g | 15 g | 20 gbalanced against calcium |
| Salt (sodium) | 0.02 g Na | 11 g Na ≈ 28 g salt | almost nonehay is low in sodium: add a salt block |
| Vitamin E | 1 IU | 550 IU | little leftlost during drying and storage |
| Water | 50–60 ml | 27.5–33 L | hay is 12% waterfresh water, always |
ⓘRequirements per NRC (2007) for a 550 kg adult horse in light work, with no grazing: hay is the whole ration. Supply from the Q3-2026 Meadow certificate (8.1% protein, 1.86 Mcal/kg, 88% dry matter). A horse at rest needs about 18.3 Mcal and 693 g of protein.
Vitamins: what grass gives, and what hay loses
We assume a horse that gets no grass. In most of Portugal and Spain turnout is limited and hay is the entire diet, so that is what every figure on this page is based on. It matters most here: fresh grass is a vitamin factory, and drying plus months of storage undo much of it. If your horse does graze daily, it covers part of this itself and needs less from the bucket.
| Vitamin | 550 kg horse per day | In fresh grass | After drying & storage | Supplement? · where else |
|---|---|---|---|---|
| A beta-carotene | 16,500 IU | Very high: green grass is packed with beta-carotene, which the horse converts to vitamin A. | Falls fast. After six months in the barn, hay retains only a fraction. | Yes for horses with little or no pastureGrazing, carrots, a balancer, alfalfa |
| E tocopherol | 550 IU more in work or breeding | High in fresh, growing grass, and it is the horse’s main natural source. | Much is lost in drying and keeps declining in storage, hay is a poor source. | Yes, this is the one most worth adding for horses on hayGrazing, natural vitamin E, linseed or oil, a balancer |
| D | 3,630 IU | Made in the skin from sunlight; sun-cured hay adds some. | Reasonably stable, but daylight matters more than the hay. | Rarely here: Portuguese and Spanish sun covers it, unless a horse is stabled all dayDaylight outdoors, sun-cured hay, a balancer |
| K | No published requirement | Green forage supplies it, and gut microbes make more. | Lower than in grass, but the hindgut keeps producing it. | No, deficiency is very rareGreen forage and the horse’s own hindgut |
| B group incl. biotin, B12 | No published requirement | Grass contributes, but most comes from the horse’s own hindgut microbes. | Unaffected as long as the fibre supply keeps the microbes healthy. | Only for a specific reason, such as biotin for poor hoovesHindgut microbes on fibre, brewer’s yeast, a balancer |
| C | No published requirement | The horse makes its own in the liver, it does not depend on feed. | Not relevant. | Only in specific cases: old, ill or heavily stressed horsesThe horse’s own liver |
ⓘRequirements per NRC (2007) for a 550 kg adult horse at maintenance. This is the honest reason a balancer exists: not to add protein, which good forage already covers, but to replace the vitamins that grass had and hay no longer does.
And the part no bag can replace: chewing time
Chewing is what makes saliva, and saliva is the horse’s only buffer against a stomach that produces acid around the clock. It is also why the same nutrients delivered in a scoop are not the same thing at all: the numbers match, the hours don’t.
Where do nutrients come from?
Four categories, four different jobs. None of them is "good" or "bad", each was designed to provide something specific.
🌾 Forage
The foundation
- Designed to provide
- Fibre, energy, protein, chewing time, gut health
- Strengths
- Natural intake, hours of chewing, steady energy, a healthy hindgut
- Limitations
- Quality varies enormously, nutrients depend entirely on the field, harvest and storage
- Typical use
- 85–100% of the ration, day and night
🍳 Concentrates
The top-up
- Designed to provide
- Concentrated energy and protein in a small volume
- Strengths
- Fast energy for hard work, precise amounts, easy to feed
- Limitations
- Starch and sugar load, small stomach capacity, no chewing time
- Typical use
- 0–4 kg/day depending on forage quality and workload
⚖️ Balancers
The insurance
- Designed to provide
- Vitamins, minerals and amino acids without calories
- Strengths
- Fills micronutrient gaps for horses that need no extra energy
- Limitations
- No energy, won't help a horse that needs condition
- Typical use
- 100–500 g/day, especially for horses that gain weight easily
💊 Supplements
The specialists
- Designed to provide
- One targeted extra: joints, hooves, electrolytes, calm…
- Strengths
- Precision for a specific, identified need
- Limitations
- Can't fix a ration that's wrong at the base
- Typical use
- Only when a specific need is identified
Our three forages, measured, not estimated
Every figure below comes from independent laboratory analysis of the current Q3-2026 batches, NIRS, Van Soest fibre fractions, INRA reference methods. And they are the same numbers our feeding calculator computes with: one dataset, everywhere.
Meadow hay
Longchamp
Alfalfa
ⓘQ3-2026 batch certificates, analysed by an independent accredited feed laboratory. Energy (DE) derived from ADF and crude protein via the NRC (2007) equation. Full certificates on the lab results page.
What each number means, and for which horse it matters
Tap a value to learn how to read it on any lab report, not just ours.
Crude protein — the builder
the raw material for muscle, topline, hooves, skin and milk. Grass hay ranges roughly 6–14% DM; our Meadow measures 8.1%, Alfalfa 18.4%.
an adult 550 kg horse at rest needs about 693 g of crude protein a day, and 10 kg of Meadow already delivers that. Work, growth, pregnancy and milk raise the need.
sport horses (Longchamp, 11.6%), broodmares in late pregnancy, lactating mares and youngsters, which is exactly when a slice of Alfalfa earns its place.
poor topline, slow recovery, dull coat. Too much: not dangerous, but wasted money and more ammonia in the stable air.
Sugar + starch (NSC) — the safety number
water-soluble sugars plus starch. The one figure you cannot see, smell or guess, a bright, sweet-smelling bale can be the dangerous one.
below 10% is the guideline for metabolic horses; 10–12% is caution; above 12% avoid. Meadow measures 4.5%, Longchamp around 10%.
horses with laminitis, EMS, PSSM or Cushing’s (PPID), horses that gain weight easily, ponies and Iberian breeds. For them: low-NSC forage always, and never less than 1.5% of bodyweight in forage per day.
healthy horses in real work handle more NSC without trouble.
Digestible energy (DE) — the fuel gauge
the calories a horse can actually use, in Mcal per kg of dry matter, calculated from fibre and protein with the NRC (2007) equation you’ll find in chapter 8.
at 1.86 Mcal/kg, Meadow carries maintenance and light work on forage alone. Longchamp’s 2.04 covers most of a sport horse’s day.
hard-working horses, hard keepers and lactating mares, denser forage first, oil or feed only for what remains.
Horses that gain weight easily. The answer is a lower-energy forage, never less forage: below roughly 1.5% of bodyweight the ulcer and boredom-behaviour risk climbs fast.
Fibre (NDF · ADF · lignin) — structure and digestibility
NDF is the plant’s cell walls (chewing time), ADF the harder-to-digest part, lignin (ADL) the part no horse digests at all.
higher NDF means more mature, coarser hay, horses voluntarily eat less of it. Lower ADF and lignin mean more energy released in the hindgut. Longchamp’s low lignin (4.7%) is why its fibre digests so well.
every horse needs long fibre for a healthy gut; seniors with worn teeth do better on leafier, softer hay; ulcer-prone horses need forage in front of them around the clock.
Ca : P — bone and balance
calcium and phosphorus, read together, bone strength depends on the ratio, not just the amounts. Target ≈ 1.5–2 : 1.
Meadow sits at 1.9 : 1, exactly in the window, so a forage-first ration balances itself. Grain-heavy rations tip toward phosphorus.
at 5 : 1 by design it corrects grain-rich rations; for growing youngstock keep the total ration under about 3 : 1.
youngsters (bone development), broodmares, and any horse on large grain meals or rice bran.
Dry matter (88%) — the water you can’t see
Hay is not dry. About 12% of every bale is still water; the other 88% is dry matter, the part that actually feeds the horse. Our Meadow measures 88%.
Anything below roughly 85% dry matter (more than 15% moisture) heats in the stack, moulds, and in bad cases can even catch fire. Between 86 and 90% hay is stable and keeps for a year or more, so 88% sits comfortably in the safe window.
You pay for the water too. 11 kg of hay at 88% dry matter gives 9.7 kg of real feed; at 80% only 8.8 kg. Same price, half a kilo of feed less, every single day.
Freshly baled hay needs about four to eight weeks to finish curing before it feeds at its best. After that, well-cured hay stored dry and off the ground holds its protein, fibre and energy for a year; only the vitamins fade with time.
Which forage for which horse?
| Horse profile | Start here | Why |
|---|---|---|
| Leisure & light work | Meadow, 1.5–2% of bodyweight in dry matter | Covers protein and energy with low sugar; most horses need little more than a balancer. |
| Sport & hard work | Longchamp, or Meadow + Longchamp | More protein and energy from forage means smaller scoops. Not for sugar-sensitive horses. |
| Easy keeper · laminitis · EMS | Meadow only (4.5% NSC) | Lower-energy, low-sugar forage, and never less than 1.5% of bodyweight in dry matter per day. |
| Broodmare · lactating | Meadow + 25–35% Alfalfa + balancer | Protein and calcium demand jumps; early lactation also needs concentrate. |
| Growing (0–3 y) | Meadow + up to 33% Alfalfa + balancer | Steady growth wins; never a high-energy base, rapid growth risks bone problems (DOD). |
| Senior | Meadow, leafy and soft; + 20% Alfalfa if topline drops | Easier chewing, a steady gut, and protein to support an ageing topline. |
ⓘThis is exactly the logic our feeding calculator applies, it chooses between these same plans for your horse’s profile. Try it with your horse →
Slide from poor hay to premium hay
This is a 550 kg horse in light work eating 11 kg of hay a day. Only one thing changes: the quality of the hay. Watch what happens to everything else.
If your forage already supplies
most of the nutrients…
…why would your horse still need
the same amount of concentrate?
Why sugar is the number you can’t guess
Non-structural carbohydrate (NSC), the water-soluble sugars plus starch, is the single figure that matters most for a growing group of horses: those prone to laminitis, Equine Metabolic Syndrome and PPID (Cushing’s). For them, a spike in blood sugar and insulin can trigger a laminitic episode.
The widely used guideline is to keep total dietary NSC below about 10–12% for at-risk horses. The catch: the same field can produce hay at 8% one week and 18% the next, depending on grass species, sunshine, plant stress and cutting time, and none of it is visible. A bright, sweet-smelling bale can be the dangerous one.
Testing every batch is the only way to feed metabolic horses with confidence, and to prove a batch is safe rather than hope it is.
The part of hay a horse breathes, not eats
Equine asthma (the condition formerly split into RAO and IAD) is one of the most common performance-limiting problems in stabled horses, and its single biggest environmental driver is the respirable dust in forage: mould spores and fine particles small enough to reach deep into the lung.
A horse eats with its muzzle buried in the hay for much of the day, so what it inhales there matters as much as what it digests. Double-pressing shakes loose the fine particles and mould dust that would otherwise stay in the bale, lowering the respirable load without soaking away nutrients or sugars. It’s why respiratory-sensitive and sport horses do better on clean, screened forage.
A gut designed for forage, around the clock
The horse is a hindgut fermenter and a trickle feeder: evolved to graze fibrous forage for most of the day, not to take two large meals. Its physiology is exactly why forage isn’t “just roughage”, it’s the foundation the whole system is built on.
Chewing forage produces saliva that buffers a stomach which secretes acid continuously, the horse’s natural defence against gastric ulcers. Long gaps without forage, or diets low in fibre and high in starch, remove that buffer and unsettle the hindgut microbes. Feed enough good forage and most of the horse’s digestive needs look after themselves.
Follow forage from mouth to colon
Why concentrates exist at all
For most of history, horses lived on forage. But traditional hay had a problem: nobody knew what was in it. One year the meadow was rich; the next year the same field produced hay with barely any protein. Working horses lost condition on poor batches.
Feed manufacturers solved this brilliantly. Concentrates delivered guaranteed, consistent nutrients in every scoop, whatever the hay happened to contain. It worked, and it changed feeding culture: the scoop became the meal, and hay became "just roughage".
Concentrates solved a real problem: unpredictable forage. Hold that thought.
But that fixed the symptom, not the cause. The problem was never forage, it was not knowing what the forage contained. So here is our question: what if the hay were predictable again, every batch laboratory-tested, so you knew its protein, sugar and fibre before it ever reached the manger?
That is exactly what Prime Hay does. We are not saying concentrates are useless, hard-working and special-needs horses still earn their scoop. But when your forage is tested, consistent and honest, concentrate goes back to being a top-up, not the meal: you feed it to fill a gap you can see, not to insure against one you can’t.
Protein is protein. Energy is energy.
On a lab report, a gram of protein from hay is identical to a gram from a feed bag, because it is. Nutrients don’t care where they come from. What changes everything is the package they travel in:
Forage releases those nutrients slowly, wrapped in fibre, across 14+ hours of chewing, exactly the way a horse’s gut evolved to receive them. A scoop of concentrate hands over the same numbers in minutes, with a spike of starch and sugar along for the ride. Same nutrients, a completely different journey.
That journey is the whole point. When the forage is right, the nutrients arrive the way nature intended — slow, steady and kind to the gut — and the scoop goes back to being a finishing touch, not the meal.
The same horse, two feeding strategies
Where the daily nutrition actually comes from. Same horse, same requirements, a different foundation.
Traditional feedingpoor hay + big scoops
- Gut works hardest on the smallest part of the diet
- High starch load, meal spikes
- Nutrition depends on the bag
Forage-first feedinganalysed hay + small top-up
- Nutrition arrives the way the gut evolved for
- Low starch, steady energy
- The scoop only tops up what's missing
Forage Concentrates Balancer & supplements
Two diets can meet the same energy requirement and still have very different forage foundations. A ration shouldn’t score the same when poor forage forces a large scoop to reach the same final numbers as good forage reaches on its own. Good forage should do as much of the nutritional work as it reasonably can; concentrate exists to fill whatever gap is left, not to carry the ration.
The modern forage philosophy
This isn't Prime Hay's opinion, it's where equine nutrition science has landed:
- Maximise forage. It should carry as much of the ration as its quality allows.
- Concentrates only fill gaps. Add them where forage genuinely can't meet requirements, not by habit.
- Protect the gut. Long fibre, long chewing, feed little and often.
- Avoid unnecessary starch. Every kilo of concentrate you don't need is a win for the stomach.
- Measure, don't guess. You can't feed to requirements if you don't know what's in your forage.
We publish our maths. Here it is.
Our feeding calculator isn’t a marketing quiz, it’s a nutrition engine built on the published NRC (2007) Nutrient Requirements of Horses, the standard professional nutritionists work from. This is genuinely how it computes, step by step.
DE (Mcal/kg DM) = 4.22 − 0.11×ADF + 0.0332×CP + 0.00112×ADF²
// Worked example — our Meadow hay (ADF 41, CP 8.1):
4.22 − 4.51 + 0.27 + 1.88 = 1.86 Mcal/kg DM ← the exact figure on our lab page
The intake ceiling comes first
A horse can only eat so much: 2.5% of bodyweight in forage dry matter per day (2.0% in late pregnancy, up to 3.0% when lactating). Every plan is solved inside that ceiling, we never recommend a ration a horse can’t physically eat.
Requirements from bodyweight, work and life stage
Energy and protein needs are computed per horse: maintenance = 0.0333 Mcal DE per kg bodyweight, multiplied by workload, with separate coefficient curves for growing horses, pregnancy (by month) and lactation.
Your current ration, with real label data
What you feed now is looked up in our database: 18 brands, ~200 named products, Pavo, Cavalor, St. Hippolyt, Red Mills, Reverdy, AGROBS and more, each with its actual protein, starch, sugar and energy values.
Forage-first solving, several plans compete
The engine builds multiple candidate rations (Meadow only, Meadow + Alfalfa blend, Longchamp for sport horses) and picks the one that leans hardest on forage, the smallest bag of concentrate wins, cost as tie-break. The runner-up is shown as Option B, so you choose.
Hard safety limits, built in
Concentrate is capped at 5 kg/day, oil at 100 ml per 100 kg bodyweight, starch is flagged above 2 g/kg BW/day. Sugar-sensitive or easy-keeper horses are locked to low-sugar Meadow, the engine structurally cannot recommend Longchamp for them. Growing horses never get Longchamp as a base.
And if the numbers don’t close, we say so
When no forage mix plus the capped top-ups can meet a requirement (early lactation, for example), the calculator tells you honestly that forage alone won’t do it, instead of pretending it does.
The workload multipliers, exactly as coded
| Workload | Energy × maintenance | Protein g × bodyweight kg |
|---|---|---|
| Rest | × 1.00 | × 1.26 |
| Light work | × 1.20 | × 1.40 |
| Moderate | × 1.40 | × 1.55 |
| Sporty | × 1.60 | × 1.724 |
| Intense | × 1.90 | × 2.008 |
ⓘMultiples of maintenance, per NRC 2007. The same numbers a professional ration evaluation uses.
Meeting the requirement is only half the story
NRC (2007) is what calculates what your horse requires — everything above this line. The Prime Hay Forage-First Score is a separate step on top of that: it looks at the ration NRC just measured and asks how it gets there — whether forage supplies the nutritional foundation, or a hard feed has to compensate for a weak one. The Forage-First Score is a Prime Hay methodology, not an NRC score.
Forage foundation covers the amount fed, and how much of the horse’s energy and protein forage itself supplies. Total coverage checks the ration against requirement, energy and protein each. Concentrate dependence looks at how much of that requirement a hard feed has to close — not whether one is fed at all. A sport horse, a broodmare or a growing youngster can legitimately need real concentrate; the score measures unnecessary dependence caused by a weak forage foundation, not appropriate supplementation. Chewing time and starch safety are real and stay on the result page, they are deliberately not part of this number, so a score is never read as a verdict on either.
Now see how forage-first your horse’s current diet really is.
Calculate my horse →
Numbers we threw away
Trust in data means rejecting bad data, including our own.
The alfalfa fibre figures
An earlier alfalfa report contained a fibre result that was chemically impossible (ADF higher than NDF). We discarded it and used a clearly-labelled conservative estimate instead, until the current batch passed the same sanity check (NDF 43, ADF 35) and earned a real, lab-derived energy value. Every number has to pass that gate.
Lysine we haven’t measured
No forage lab report we hold measures lysine. So the calculator computes your horse’s lysine requirement, but never invents a supply figure. Where we have no measurement, we show no number.
Rations that don’t close
For some horses, a mare in early lactation, a hard-working sport horse on limited hay, forage genuinely can’t cover everything. The calculator says exactly that, and shows what’s missing, instead of bending the maths to make a sale.
Every number on this website traces to a lab report, a manufacturer label or a published standard. When one of those changes, the site changes. That’s the whole system.
How much of your horse's nutrition
already comes from forage?
Two minutes. Your horse's weight, work and current hay, and you'll see the protein gap, the concentrate need and the honest monthly cost, side by side.
Frequently asked
Why Prime Hay exists
If you've read this far, you already understand our whole philosophy: the more nutrition that comes naturally from forage, the less a horse depends on concentrates. Everything we do serves that idea:
- Laboratory testing, every batch. Protein, energy, sugar, measured, not assumed. Average protein ≈ 8.1% against as little as 2–5% in typical local hay.
- Harvest management. Cut at the right moment from managed French meadows, for consistent nutrients year-round.
- Consistency. The same analysed quality in January and in July, so your ration keeps working.
- Low-dust, double-compressed. Kinder to airways, easier to store, less waste.
Nothing exaggerated. Only measurable facts, because that's the whole point.
Feeding guides
Practical, evidence-based guides on choosing and feeding hay.