This guide is about how much: the amount of hay, concentrate feed, and water a horse needs per day, worked out from its weight and the work it does. How to build a ration and feed it, including spreading it over the day, hay quality, supplements, and preventing colic, is covered in Feeding Your Horse Well: Hay, Concentrates, and Supplements.
A horse digests small amounts of forage all day long; how much it needs depends on its weight and the work it does. Below you see how to work out from those two facts how much forage and concentrate feed fits.
Start with the Weight
Almost every feed calculation starts with body weight. Few stables have a weighbridge, so most owners work with an estimate:
- Weight tape: a tape you wrap around the girth, gives a rough indication. Allow for a margin of several tens of kilos.
- Girth-and-length formula: girth and body length together give a more accurate estimate than the tape alone.
- Type and build: an average riding horse sits roughly between 500 and 650 kg, a pony considerably lower, a cold-blood breed higher.
The exact number doesn't need to be perfect. It serves as a starting point for basing the daily amount of forage on, and you then adjust based on what you see and feel on the horse.
How Much Hay per Day
Forage (hay or haylage) forms the basis of the ration. The CVB (Centraal Veevoederbureau, the Dutch central bureau for livestock feed) assumes in its table book for horses at least 1 kg of dry matter in long forage per 100 kg of body weight: at least 1 percent of body weight in forage per day. A horse fed forage only eats, depending on quality, about 2 percent of its body weight in dry matter; with concentrate feed added, the maximum total intake is about 2.5 percent. For a normal horse in maintenance, the KNHS (the Dutch equestrian federation) gives 1 to 1.5 percent in forage, and the Merck Veterinary Manual gives 2 to 2.5 percent dry matter in total as a starting point for a healthy horse, at least half of it from forage. The sources thus give a range, not a fixed number: treat it as a rule of thumb and adjust to your horse's condition and work.
A few examples, converted to hay:
| Body Weight | Forage per Day (Dry Matter, 1 to 2 percent) | Roughly in Kilos of Hay |
|---|---|---|
| 400 kg (pony) | 4–8 kg | 4.5–9 kg |
| 550 kg (riding horse) | 5.5–11 kg | 6–12 kg |
| 650 kg (heavier horse) | 6.5–13 kg | 7–15 kg |
Hay itself still contains some moisture, so the weighed amount sits a bit above the dry-matter figure; hence the higher numbers in the right-hand column. The CVB uses just over 88 percent dry matter for coarse grass hay. A 550 kg riding horse that eats only hay (about 2 percent dry matter) comes to just over 12 kg of hay a day this way: about 4.5 tons a year. With concentrate feed or grazing added, it is less.
More important than the exact kilos is spreading the forage across the day. Why that matters and how to do it is covered in Feeding Your Horse Well.
When Concentrate Feed Is Needed
Concentrate feed is a supplement to forage, not a replacement. It provides extra energy and protein for horses that genuinely do work. The question isn't whether you "have to" give concentrate feed, but whether your horse's work calls for that extra energy.
A rough breakdown by workload:
| Workload Level | Example | Concentrate Feed |
|---|---|---|
| Maintenance | Ridden little or not at all | Often none, only minerals |
| Light work | Ridden gently a few times a week | Little to none |
| Moderate work | Training almost daily, lower classes | Limited, as needed |
| Heavy work | Intensive training, higher classes, many competitions | More, in small portions |
A recreational horse often manages fine on good forage plus a mineral and vitamin supplement. A horse in a demanding competition program is more likely to need extra energy. Match the amount to the work, not the other way around: a horse shouldn't have to work harder to burn off its feed. Adjust the concentrate feed downward on rest days.
How to split concentrate feed over the day and give it together with forage is covered in Feeding Your Horse Well.
Adjusting Energy: Gaining or Losing Weight
Whether the ration is right shows up mainly on the horse itself, not on the feed bag's scale. The body condition score is the handiest tool for that: you feel and look at the fat covering on the ribs, back, shoulder, and tailhead. A rule of thumb is that you should be able to lightly feel the ribs, but not clearly see them.
- Too thin (ribs visible, sunken): needs more energy. Increase the forage first, then adjust concentrate feed if needed; also check teeth and deworming.
- Too heavy (ribs not palpable, rolls of fat): needs less energy. Scale back sugar- and starch-rich feed and focus on more exercise rather than a strict starvation diet.
Always change gradually. Why that matters so much, and how to prevent colic and laminitis, is covered in Feeding Your Horse Well.
Water and Salt
Feeding doesn't stop at hay and concentrate. How much a horse drinks varies widely. According to the Merck Veterinary Manual, the minimum need of an adult horse at rest in moderate temperatures is about 5 liters per 100 kg of body weight per day: a 500 kg horse then usually drinks 21 to 29 liters on a ration of hay and concentrate feed or grass. If it gets only dry hay, that can almost double, and sweat losses and milk production raise the need by 50 to 200 percent. A 500 kg horse that works for an hour in the heat may need more than 72 liters. Make sure clean water is available unlimited, and keep water troughs frost-free in winter: drinking too little is itself a risk factor for colic.
Every horse also needs salt. A salt lick or added table salt covers the basic need. Horses that sweat heavily, for example on a hot competition day, lose extra salts; electrolytes after exertion can be worthwhile in that case.
In Short
- Estimate body weight with a tape or formula and use that as a starting point.
- Count on at least 1 percent of that weight in forage per day (dry matter); a horse fed forage only eats about 2 percent.
- Give concentrate feed only as far as the work requires.
- Adjust based on the horse's condition, not a fixed number: feel for the ribs.
- Keep clean water available unlimited.
A hay or grass analysis shows how much energy and protein your forage actually contains; your vet or a feed advisor can use that to tailor a ration that fits your horse's weight, age, and work. To recognize abdominal pain and other warning signs, see Colic in Horses.
Sources (verified September 2, 2026, sources deepened, forage and water November 2, 2026): Utrecht University Veterinary Hospital: Equine metabolic syndrome (EMS) · NRC Nutrient Requirements of Horses (2007) · Wageningen University & Research: CVB Table Book on Feeding Horses and Ponies (2013), section 9.1 · KNHS: Goede voeding (good feeding) · Merck Veterinary Manual: Feeding Practices in Horses and Other Equids · Merck Veterinary Manual: Nutritional Requirements of Horses and Other Equids
See also: Feeding Your Horse Well: Hay, Concentrates, and Supplements · Colic in Horses