Use our free horse nutrition calculator to find your horse’s daily energy, protein, and mineral requirements based on body weight, life stage, and work level. Based on NRC (National Research Council) 2007 guidelines.
Horse Daily Energy Requirements (Digestible Energy)
| Horse Weight | Maintenance | Light Work | Moderate Work | Heavy Work |
|---|---|---|---|---|
| 400 kg (880 lb) | 13.4 Mcal | 16.1 Mcal | 18.7 Mcal | 21.6 Mcal |
| 500 kg (1,100 lb) | 16.7 Mcal | 20.1 Mcal | 23.3 Mcal | 27.0 Mcal |
| 600 kg (1,320 lb) | 20.0 Mcal | 24.0 Mcal | 27.9 Mcal | 32.4 Mcal |
| 700 kg (1,540 lb) | 22.4 Mcal | 26.9 Mcal | 31.2 Mcal | 36.2 Mcal |
Horse Protein Requirements (500 kg Horse)
| Life Stage | Daily Crude Protein | Dietary CP % | Daily Lysine |
|---|---|---|---|
| Maintenance adult | 630 g/day | 8–9% | 27 g/day |
| Light to moderate work | 700–800 g/day | 10–12% | 30–36 g/day |
| Heavy / very heavy work | 900–1,000+ g/day | 12–14% | 40–48 g/day |
| Pregnant mare (late) | 840 g/day | 11–12% | 36 g/day |
| Lactating mare (peak) | 1,500+ g/day | 14–16% | 84 g/day |
| Weanling (6 months) | 630 g/day | 14.5% | 35 g/day |
Horse Mineral Requirements (500 kg, Maintenance)
| Mineral | Daily Need | Key Function | Primary Sources |
|---|---|---|---|
| Calcium (Ca) | 20 g/day | Bone, teeth, muscle | Alfalfa, limestone supplement |
| Phosphorus (P) | 14 g/day | Bone, energy metabolism | Grains (avoid excess bran) |
| Magnesium (Mg) | 7.5 g/day | Neuromuscular function | Grass hay, Mg oxide supplement |
| Sodium (Na) | 10 g/day | Fluid balance, nerve function | Free-choice salt block (essential) |
| Selenium (Se) | 1 mg/day | Antioxidant, muscle health | Se-yeast supplement (often deficient in US) |
| Zinc (Zn) | 400 mg/day | Immune function, hoof quality | Balanced mineral supplement |
| Copper (Cu) | 100 mg/day | Connective tissue, pigmentation | Balanced mineral supplement |
Calcium to Phosphorus ratio must always be 1:1 to 3:1 (Ca:P). More phosphorus than calcium causes Nutritional Secondary Hyperparathyroidism. Avoid large amounts of wheat bran without additional calcium.
Vitamin Requirements for Horses
| Vitamin | Synthesised? | Supplement Needed? | Notes |
|---|---|---|---|
| Vitamin A | From beta-carotene in grass | Yes, on dry hay | Vision, immunity, reproduction |
| Vitamin D | From sunlight | Only if stabled with no turnout | Bone mineralisation |
| Vitamin E | No — must come from diet | Yes, especially for performance | Critical antioxidant; supplement at 1–2 IU/kg BW |
| B Vitamins | Hindgut bacteria | Rarely; yes during stress | Biotin 20 mg/day for hoof quality |
Horse Nutrition by Life Stage
| Life Stage | Priority Nutrients | Feed Strategy |
|---|---|---|
| Mature maintenance | DE, protein, vitamin E, salt | Quality grass hay + ration balancer |
| Performance horse | DE, electrolytes, vitamin E, omega-3 | Add grain/fat; electrolytes during competition |
| Easy keeper | Minerals without calories | Ration balancer; restricted hay; slow feeder |
| Hard keeper | DE, fat, digestible protein | Add 500 ml/day oil; high-fat concentrate |
| Senior horse (20+) | Digestible protein, phosphorus, fibre | Senior feed with enzymes; soaked hay cubes if dentition poor |
Frequently Asked Questions
What nutrients do horses need daily?
Horses require daily digestible energy, crude protein (with adequate lysine), water, and a full range of macro and trace minerals including calcium, phosphorus, magnesium, sodium, selenium, zinc, and copper. Vitamins A, D, and E must come from diet or sunlight; B vitamins and K are largely synthesised internally.
How much protein does a horse need?
A 500 kg maintenance horse needs approximately 630 grams of crude protein per day, met by quality grass hay at 8–9% CP. Performance horses and growing foals need 12–16% CP diets. Lysine is often deficient in all-grass hay diets and may need supplementation.
Do horses need vitamin and mineral supplements?
Most horses on forage-only diets benefit from a ration balancer providing concentrated vitamins and minerals without added energy. Key deficiencies in hay-based diets commonly include selenium, vitamin E, zinc, and copper. Have your hay tested to identify specific gaps.
What is a ration balancer for horses?
A ration balancer is a concentrated, low-calorie pelleted supplement filling nutritional gaps in a forage-based diet without adding significant calories. It provides balanced amino acids, vitamins, and minerals at 1–2 lb per day. Ideal for easy keepers and any horse whose diet is primarily hay or pasture without grain.