How to use the horse maintenance nutrients calculator
- Enter your horse's weight (use the Horse Weight Calculator if you do not have a scale).
- Press Calculate.
Worked example
A mature 500 kg horse at maintenance.
- Horse weight (200–900 kg)
- 500 kg
- Weight
- 500 kg (1,102 lb)
- Crude protein
- 630 g
- Calcium
- 20 g
- Phosphorus
- 14 g
- Vitamin A
- 15,000 IU
Estimated average minimum requirements for a mature horse at maintenance (NRC 2007). Not a feeding plan: ask your vet or an equine nutritionist.
Example values are illustrative; this result is produced by the same calculator above.
How we calculate it
Sources: Merck/MSD Veterinary Manual · NRC
Reference table
| Weight | Digestible energy (Mcal/day) | Crude protein (g/day) | Calcium (g/day) | Phosphorus (g/day) |
|---|---|---|---|---|
| 200 kg / 441 lb | 6.7 | 252 | 8 | 6 |
| 500 kg / 1,102 lb | 16.7 | 630 | 20 | 14 |
| 900 kg / 1,984 lb | 30 | 1,134 | 36 | 25.2 |
Understanding your result
Horses need energy, protein, calcium, phosphorus and vitamins every day just to keep their body going. The National Research Council (NRC, 2007) publishes estimated average minimum daily requirements for mature horses, and the Merck/MSD Veterinary Manual reprints them in a table.
The table lists three body weights. A 200 kg pony needs at least about 6.7 Mcal of digestible energy and 252 g of protein a day; a 500 kg horse about 16.7 Mcal and 630 g; and a 900 kg horse about 30.0 Mcal and 1,134 g. This calculator returns those exact values at those weights and draws a straight line between them for weights in between.
These are minimum requirements for maintenance, which means a mature horse at rest. Horses that work, grow, are pregnant or lactate need more, and individual horses vary, so use the result as a reference point and ask your vet or an equine nutritionist before changing a diet.
Common mistakes
- Treating a minimum requirement as the amount to feed.
- Using the result for a foal, a pregnant mare or a horse in hard work.
- Entering a weight guess instead of measuring; use the Horse Weight Calculator or a weighbridge.
- Ignoring the energy and nutrients already in the hay and feed.
- Changing the diet suddenly without advice.
Good to know
- Digestible energy is measured in megacalories (Mcal); one Mcal is 1,000 kcal.
- Weights outside 200 to 900 kg are not calculated because the published table stops there.
- A forage analysis tells you what your hay actually supplies.
When to talk to your vet
- Your horse is losing or gaining weight
- Before changing a horse's diet
- Your horse is pregnant, lactating, growing or in hard work
Frequently asked questions
Where do the numbers come from?
From the NRC (2007) Nutrient Requirements of Horses as printed in the Merck/MSD Veterinary Manual table for mature horses and ponies. Values between the published weights are interpolated in a straight line.
Are these the amounts to feed?
No. They are estimated average minimum daily requirements. Your horse's actual needs depend on its work, age, condition and the feed, so ask your vet or an equine nutritionist.
Why only 200 to 900 kg?
That is the range of the published table. Outside it the calculator would have to guess, so it stops instead.
What is digestible energy?
The energy in feed that the horse can digest, measured in megacalories (Mcal). One Mcal is 1,000 kcal.
Can I use it for a pony?
Yes if its weight is between 200 and 900 kg. Ponies below 200 kg are outside the published table.
Does it cover working horses?
No. This is maintenance only. Horses in work need more; ask your vet or an equine nutritionist.
Sources
- Merck/MSD Veterinary Manual — Estimated Average Minimum Daily Nutrient Requirements of Mature Horses and Ponies (table adapted from NRC 2007)
- NRC (2007) Nutrient Requirements of Horses, 6th ed., National Academies Press
Related calculators
- Horse Weight CalculatorEstimate your horse's weight from its heart girth and body length with a tape measure.
- Horse Hay Needs CalculatorEstimate how much hay a horse eats a day as a range, from its weight and the dry-matter content of the hay, and what that means in bales and cost.
- Lactating Mare Nutrients CalculatorSee the daily minimum energy, protein, calcium and phosphorus range a lactating mare needs, from her weight and the stage of lactation.
- Horse Hay Cost CalculatorWork out how long a bale lasts and what hay costs per day, month and year.
Estimated average minimum requirements from published tables, not a feeding plan. Ask your veterinarian or an equine nutritionist. If your pet may have eaten something harmful, contact your vet or an animal poison helpline now.