Horse Nutrition Guide: Feeding Requirements, Hay, Grain & Supplements for Every Life Stage
By FarmVetGuide Editorial Team · Published March 2026 · Updated March 2026 · Based on verified data from our directory of 9,500+ practices
Feeding horses correctly is one of the most important — and most frequently misunderstood — aspects of equine management. Unlike cattle or swine, horses evolved as continuous-movement grazers on sparse, fibrous forage. Their digestive anatomy reflects this: a relatively small stomach, a large hindgut fermentation chamber, and a system designed for slow, constant movement with near-constant forage intake. Departing too far from this evolved model is responsible for a significant share of the colic, laminitis, metabolic, and behavioral problems that equine veterinarians treat every day. This guide covers nutritional requirements, forage selection, grain management, supplements, common disorders, and the special feeding needs of every life stage — from the nursing foal to the geriatric horse.
The Fundamentals of Equine Digestion
Understanding how horses digest food is essential before designing any feeding program. Horses are non-ruminant hindgut fermenters. Digestion proceeds roughly as follows:
- Stomach — Small capacity (2–4 gallons); empties quickly. Acid secretion is continuous, regardless of whether the horse is eating. An empty stomach exposed to acid is a primary driver of equine gastric ulcer syndrome (EGUS). Horses should never go more than 4–6 hours without forage access.
- Small intestine — Primary site for starch, sugar, fat, and protein absorption. Capacity limited (~70 feet long but fast-moving). Large grain meals overwhelm small intestinal starch digestion, leading to hindgut starch overflow — a leading cause of hindgut acidosis and colic.
- Cecum and large colon — The "fermentation vat." Trillions of microbes break down plant fiber (cellulose, hemicellulose) into volatile fatty acids (VFAs) — the horse's primary energy currency from forage. Any rapid dietary change disrupts microbial populations; this is why feed transitions must be slow (7–14 days minimum).
Key practical takeaways from equine digestive anatomy:
- Forage first, always — it is the foundation of every horse's diet
- Limit individual grain meals to 4–5 lbs or less (ideally 2–3 lbs in horses prone to digestive upset)
- Change feeds slowly — never switch hay type or grain product abruptly
- Feed at consistent times — horses are creatures of habit; schedule changes cause stress and digestive disruption
- Ensure constant clean water access — dehydration is a leading colic risk factor
Nutritional Requirements: The Big Picture
The National Research Council's Nutrient Requirements of Horses (6th edition, 2007) is the scientific foundation for equine nutrition in the US. Requirements are expressed per day and vary substantially by body weight, life stage, and work level. The six essential nutrient categories are:
1. Water
Often overlooked, water is the most critical nutrient. A 1,100-lb horse at maintenance needs 6–10 gallons of water per day. Requirements double or more with heat, exercise, lactation, or dry feed diets. Horses are sensitive to water temperature and taste; they may dramatically reduce intake if water is too cold (below 45°F) or has an unfamiliar mineral taste. Automatic waterers should be checked daily for function and cleanliness.
2. Energy (Calories)
Energy is measured in megacalories (Mcal) of digestible energy (DE). A 1,100-lb horse at maintenance needs approximately 16.7 Mcal DE/day. Requirements scale with:
| Life Stage / Work Level | DE Requirement (1,100-lb horse) | Increase vs. Maintenance |
|---|---|---|
| Maintenance (adult idle) | 16.7 Mcal/day | Baseline |
| Light work (trail, occasional arena) | 20.1 Mcal/day | +20% |
| Moderate work (regular training, ranch work) | 23.4 Mcal/day | +40% |
| Heavy work (competitive, intense daily training) | 29.5 Mcal/day | +75% |
| Very heavy work (racing, 3-day eventing) | 33.4–41.8 Mcal/day | +100–150% |
| Late gestation (last 3 months) | 19.4 Mcal/day | +16% |
| Early lactation (first 3 months) | 28.3 Mcal/day | +69% |
| Weanling (6 months, 440 lb) | 13.4 Mcal/day | N/A |
3. Protein
Protein quality (amino acid profile) matters as much as quantity. Lysine is the first limiting amino acid for horses — the one most likely to be deficient and cap overall protein utilization. Threonine and methionine are also important. Crude protein (CP) requirements:
- Maintenance adult: 630–700 g CP/day (~1.4 lb)
- Weanling: 630–900 g CP/day (higher relative to body weight)
- Pregnant mare (late gestation): 950–1,050 g CP/day
- Lactating mare (peak): 1,500–1,700 g CP/day
- Performance horse (heavy work): 900–1,100 g CP/day
High-protein diets (above 14% CP for maintenance horses) are not harmful in adult horses with healthy kidneys, but excess protein is metabolized and excreted as nitrogen (ammonia in urine) — wasted dollars and increased ammonia in stalls. Target CP to the horse's actual needs.
4. Minerals
Macro-minerals (grams per day) and trace minerals (milligrams per day) are critical for bone health, muscle function, nerve signaling, and enzymatic reactions. The most important and commonly imbalanced minerals in horse feeding:
| Mineral | Maintenance Requirement | Key Role | Common Concern |
|---|---|---|---|
| Calcium (Ca) | 20 g/day | Bone, muscle contraction | Grass hay diets may be low; alfalfa is high |
| Phosphorus (P) | 14 g/day | Bone, energy metabolism | Ca:P ratio must exceed 1.2:1; inversion causes bone disease |
| Magnesium (Mg) | 7.5 g/day | Nerve function, enzyme activation | Lush spring grass can deplete Mg (grass tetany risk) |
| Sodium (Na) | 10 g/day | Fluid balance, sweating | Often deficient; free-choice salt block is essential |
| Selenium (Se) | 1 mg/day | Antioxidant (with Vit E), muscle health | Highly regional — deficient in NW, NE; toxic in Great Plains soils |
| Copper (Cu) | 100 mg/day | Connective tissue, pigment | Often low in hay-based diets; important for growing horses |
| Zinc (Zn) | 400 mg/day | Immune function, hoof quality | Cu:Zn ratio matters; high Zn in some water sources |
| Iodine (I) | 3.5 mg/day | Thyroid function | Kelp/seaweed supplements can cause iodine toxicity |
Selenium is the most geographically variable mineral in the US. Horses in the Pacific Northwest, Great Lakes region, and New England are frequently selenium-deficient. Horses in parts of Wyoming, South Dakota, and Nebraska may be exposed to seleniferous soils through local hay. Always know the selenium status of your forage region before supplementing; selenium toxicity (blind staggers, hair and hoof loss) is as dangerous as deficiency (white muscle disease, myopathy).
5. Vitamins
- Vitamin A — Converted from beta-carotene in fresh forage. Horses on fresh pasture or high-quality green hay rarely need supplementation. Horses on hay stored more than 6 months and with no pasture access may need supplemental Vitamin A.
- Vitamin D — Synthesized through skin exposure to UV light. Horses with outdoor access typically meet requirements. Confinement horses (particularly in northern winters) may need supplementation.
- Vitamin E — The most important dietary antioxidant for horses. Fresh pasture is an excellent source. Horses on hay diets (Vitamin E degrades rapidly after cutting) are frequently deficient. Supplementation at 1,000–2,000 IU/day (as natural-source d-alpha-tocopherol) is beneficial for performance horses, horses with muscle disorders (PSSM, EMND, EDM), and all horses without pasture access. This is a very common and clinically meaningful deficiency in stabled horses across the US.
- B vitamins — Synthesized by hindgut microbes in adequate amounts for healthy horses. Horses under stress, on antibiotics, or with hindgut dysbiosis may benefit from B-vitamin supplementation. Biotin (20 mg/day) has evidence for improving hoof quality in horses with brittle or shelly hooves.
6. Fats
Horses digest fat efficiently (up to 20% of diet as fat); added fat is an excellent calorie-dense energy source that does not cause the insulin and behavioral spikes associated with grain starch. Rice bran, stabilized flaxseed, and vegetable oils (corn, soy, canola) are common fat sources. Fat is especially useful for:
- Performance horses needing calorie density without starch load
- Horses prone to tying-up (PSSM, RER) — fat replaces starch and glycogen dependence
- Hard keepers who need more calories without more grain volume
- Horses with gastric ulcers — fat does not stimulate acid secretion the way starch does
Forage: The Foundation of Every Equine Diet
Forage — hay or pasture — should constitute at minimum 1.5% of body weight per day on a dry matter basis. For a 1,100-lb horse, that is at least 16.5 lbs of hay per day. Most horses do best at 2–2.5% of body weight, meaning 22–27.5 lbs of hay daily. Cutting below 1.5% body weight causes gastric ulcers, hindgut acidosis, wood chewing, coprophagia, and stereotypies (cribbing, weaving).
Hay Types and Their Nutritional Profiles
| Hay Type | Typical DE (Mcal/lb) | Typical CP (%) | Ca:P Ratio | Best For |
|---|---|---|---|---|
| Timothy (mature) | 0.86 | 7–10% | 1.2:1 | Maintenance, easy keepers, senior horses |
| Orchardgrass | 0.88–0.92 | 10–14% | 1.5:1 | Moderate work, young horses |
| Bermudagrass | 0.83 | 9–12% | 1.1:1 | Maintenance in Southeast/Southwest |
| Alfalfa (leafy) | 1.0–1.1 | 18–22% | 5:1 to 7:1 | Lactating mares, growing horses, performance, underweight |
| Alfalfa-grass mix (50/50) | 0.92–0.96 | 14–16% | 2.5:1 to 4:1 | Performance horses, weanlings, pregnant mares |
| Oat hay (mature) | 0.82–0.88 | 7–10% | 0.5:1 (invert risk) | Limited use; watch Ca:P ratio |
| Sudan/sorghum-Sudan | 0.82–0.86 | 10–14% | Varies | Not recommended — prussic acid and nitrate risk |
Alfalfa notes: The high calcium, high protein, and high energy density of alfalfa make it valuable for horses with elevated needs (lactating mares, growing horses, hard-working performance horses, underweight horses). For easy-keeper mature horses at light work, pure alfalfa diets can lead to excess calorie and protein intake, obesity, and elevated blood urea nitrogen (BUN). A grass-alfalfa mix is often ideal for most horses.
A practical hay quality tip: Get your hay tested. A basic NIR forage analysis costs $20–$35 at most extension-affiliated labs. It tells you actual DE, CP, ADF, NDF, calcium, phosphorus, and often selenium. Without testing, you are guessing — and potentially under- or over-supplementing your horses.
Hay Quality Assessment
In the field, evaluate hay for:
- Color — Green indicates good beta-carotene and vitamin content; tan/yellow signals sun bleaching and nutrient loss
- Smell — Sweet, fresh grass/hay smell; mold smell is a deal-breaker
- Maturity at cutting — Pre-bloom or early bloom alfalfa, boot-to-heading grass = higher quality than late-cut, stemmy hay
- Leaf-to-stem ratio — More leaves = higher protein and digestibility
- Dust and mold — Never feed dusty or moldy hay. Dust causes heaves (COPD/RAO); mold can produce mycotoxins and cause colic or liver damage
- Weeds and foreign material — Sericea lespedeza, alsike clover, and many other plants can cause photosensitivity, liver disease, or other toxicoses
Pasture Management
Fresh pasture is the ideal forage for horses — high in Vitamin E, highly digestible, and behaviorally satisfying. However, it comes with risks that must be managed:
- Lush spring grass — High non-structural carbohydrate (NSC) content in rapidly growing cool-season grasses (fescue, orchardgrass, bluegrass) in spring triggers insulin spikes and is the leading cause of spring laminitis in insulin-resistant horses and ponies. Limit access to 1–2 hours/day or use a grazing muzzle.
- Fescue toxicosis — Endophyte-infected tall fescue (Festuca arundinacea infected with Neotyphodium coenophialum) is the dominant grass in horse pastures throughout the Southeastern and lower Midwest US. The endophyte produces ergot alkaloids that cause prolonged gestation, thickened placentas, agalactia (no milk production), weak foals, and mare infertility. Pregnant mares must be removed from endophyte-infected fescue pastures no later than 60–90 days before foaling.
- Photosensitizing plants — White and alsike clover, buckwheat, and St. John's wort in pastures can cause liver damage and secondary photosensitization, particularly in horses with pink skin.
- Rotational grazing — Resting pastures allows grass recovery, reduces parasite exposure (larvae desiccate), and prevents overgrazing that leads to weed invasion and bare soil.
Grain and Concentrate Feeding
Many horses — easy-keeper adults at maintenance or light work — do not need any grain at all if high-quality forage and a vitamin-mineral supplement or balancer pellet are provided. Grain is indicated when forage alone cannot meet energy and/or specific nutrient requirements: performance horses in heavy work, lactating mares, growing horses, seniors with poor dentition, and hard-keepers in winter.
Grain Types
| Grain | DE (Mcal/lb) | Starch (%) | NSC (%) | Notes |
|---|---|---|---|---|
| Oats (whole) | 1.25 | 40–45% | 50–55% | Best-tolerated cereal grain; hull slows digestion; can feed whole |
| Corn (cracked) | 1.54 | 65–70% | 72–75% | Energy dense but high starch; must crack or steam-flake to improve digestibility |
| Barley (rolled) | 1.45 | 55–60% | 62–68% | Must process (roll/steam) — whole barley poorly digested |
| Beet pulp (unmolassed) | 1.11 | 1–5% | 10–15% | Excellent low-NSC calorie source; high digestible fiber; safe for metabolic horses; soak before feeding |
| Rice bran (stabilized) | 1.45 | 18–20% | 22–25% | High fat (18–20%); excellent calorie-dense fat source; high phosphorus — balance calcium |
| Flaxseed (ground/stabilized) | 1.65 | 2–4% | 5–8% | Omega-3 source (ALA); feed stabilized ground or whole (grind fresh); excellent for coat and inflammation |
Commercial Feeds
Textured and pelleted commercial feeds combine grains, protein sources (soybean meal), fat, and a vitamin-mineral premix in a balanced formulation. Key categories:
- Complete feeds — Include roughage fiber; intended for horses who cannot eat hay (severe heaves, poor dentition). Higher in fiber, lower in starch than typical grain mixes.
- Ration balancers / protein/mineral pellets — Low-calorie concentrates (feed 1–2 lbs/day) that balance amino acids, vitamins, and minerals in a hay-based diet without adding significant calories. Ideal for easy keepers, miniature horses, Thoroughbreds prone to obesity, and horses at maintenance on average hay.
- Performance feeds (sweet feed or textured) — Higher energy, often higher NSC. Examples: Purina Omolene 200, Nutrena Empower, Triple Crown Senior. Follow manufacturer feeding rates — they are formulated assuming those rates to provide correct micronutrient density.
- Low-starch / low-NSC feeds — Formulated for insulin-resistant, laminitic, or PSSM horses. Target total NSC below 12% for metabolic horses. Examples: Purina WellSolve L/S, Triple Crown Low Starch, Nutrena SafeChoice Metabolic.
Grain Feeding Rules
- Maximum 4–5 lbs of starch-containing concentrate per meal; break into 2–3 meals per day if total daily grain exceeds 6–8 lbs
- Feed grain by weight, not volume — density varies enormously between products
- Always feed hay before or alongside grain — fiber first buffers acid and slows starch absorption
- Transition any new grain over 7–14 days minimum to avoid hindgut dysbiosis and colic
- Wet beet pulp before feeding (soak 15–30 minutes); dry beet pulp can expand in the stomach
Supplements: What's Worth It and What's Not
The equine supplement market in the US is enormous — estimated at $800 million annually — and largely unregulated. The FDA regulates equine supplements as animal feeds, not drugs, meaning efficacy claims do not require rigorous scientific proof before marketing. Here is a practical evidence-based overview:
Supplements with Strong Evidence
- Vitamin E (natural-source d-alpha-tocopherol) — Deficiency is common in horses without pasture access. Supplementing at 1,000–5,000 IU/day (depending on body weight and condition) supports muscle health, immune function, and neurological health. Use natural form (d-alpha-tocopherol) — it has significantly better bioavailability than synthetic dl-alpha-tocopherol.
- Omega-3 fatty acids (from marine or flaxseed sources) — Reduce systemic inflammation; support coat quality, joint health, and reproductive performance. Marine-source (DHA/EPA from fish oil or algae) is better utilized than flaxseed-source ALA. Studies support joint benefits and sperm quality improvement in stallions.
- Biotin (20 mg/day) — Consistent evidence that high-dose biotin improves hoof wall quality in horses with brittle, shelly, or crumbly feet over 6–9 months of supplementation.
- Selenium + Vitamin E combination — Important for muscle health (white muscle disease prevention in deficient regions). Dose carefully — the margin between requirement and toxicity is narrow for selenium.
- Electrolytes — Essential for performance horses and horses sweating heavily in summer. A balanced electrolyte (sodium, chloride, potassium, magnesium) replaces what is lost in sweat. Note: electrolytes without water access cause dehydration — always pair with free water.
Supplements with Moderate Evidence
- Probiotics and prebiotics — Some evidence for stabilizing hindgut microbiome during dietary transitions and after antibiotic use. Benefit for healthy horses on stable diets is uncertain. Most useful during stress events (transport, competition, feed changes).
- Joint supplements (glucosamine, chondroitin, hyaluronic acid, MSM) — Mixed research results; some horses show clinical response, others do not. MSM (methylsulfonylmethane) has modest anti-inflammatory effects. Oral hyaluronic acid bioavailability is debated. Reasonable to trial in arthritic horses.
- Magnesium for "calmers" — Some horses with behavioral excitability respond to magnesium supplementation; others do not. More evidence in horses on high-NSC diets and those in regions with magnesium-poor soils or lush pastures.
Supplements with Weak or No Evidence
- Most commercial "hoof supplements" beyond biotin — Many contain a scatter of ingredients without evidence-based dosing
- Herbal calming supplements (valerian, chamomile) — Variable and inconsistent results; valerian is prohibited in competition horses under many rulebooks
- Most "immune boosters" marketed broadly — Vague claims; save money unless specific deficiency is identified
Feeding by Life Stage
Foals: Birth to Weaning (0–6 Months)
For the first 2–3 months of life, mare's milk provides essentially all nutritional needs. A healthy mare produces 3–4% of her body weight in milk per day — approximately 33–44 lbs/day for an 1,100-lb mare — and it is extraordinarily nutrient-dense. Foals begin nibbling hay and grain ("creep feed") at 2–3 weeks of age, though solid feed intake is nutritionally insignificant until 6–8 weeks.
Creep feeding (providing concentrate accessible only to foals, not mares) accelerates growth and eases the weaning transition. Formulate creep feeds to:
- 16–18% crude protein with adequate lysine
- Ca:P ratio of 1.5:1 to 2:1
- Appropriate trace mineral levels (Cu, Zn, Se, I)
- Introduce gradually starting at 4–6 weeks; limit to 0.5–1% of body weight
Overfeeding creep feed — particularly starch-heavy diets that cause rapid, excessive growth — is a recognized risk factor for developmental orthopedic disease (DOD), including osteochondritis dissecans (OCD). Target moderate, steady growth rather than maximum growth rate.
Weanlings (6–12 Months)
Weaning (typically 4–6 months of age) is one of the highest-stress events in a young horse's life. During this period:
- Provide a high-quality forage (at least 12–14% CP grass-alfalfa mix) free choice
- Feed a properly formulated weanling concentrate at 1–1.5% of body weight (approximately 5–7 lbs for a 500-lb weanling)
- Ensure adequate copper and zinc — critical for cartilage and connective tissue development
- Avoid both underfeeding (stunted growth) and overfeeding with high-starch diets (DOD risk)
- Monitor body condition score weekly; target BCS 5–6 on the Henneke 1–9 scale
Yearlings and Two-Year-Olds
Growth rate slows after the first year but musculoskeletal development continues through age 4–5. Feed requirements remain above maintenance for body weight. Commercial yearling feeds (14–16% CP) or forage-balancer combinations work well. Transitioning to adult management (forage + balancer pellet) can begin at 2–3 years for horses not in training.
Pregnant Mares
Pregnancy places significant nutritional demands on the mare, but the demands are not distributed evenly across gestation. For the first 8 months (early gestation), a mare at moderate body condition (BCS 5–6) on good-quality forage has needs only slightly above maintenance. The final 3 months — when 60–70% of fetal growth occurs — are when nutritional demands increase substantially:
- DE: +16% above maintenance (approximately 19–20 Mcal/day for 1,100-lb mare)
- CP: increase from 700g/day to 950–1,050 g/day
- Calcium: increase to 36 g/day (from 20 g at maintenance)
- Vitamin A, D, E: increase significantly
Practically: mares in late gestation on grass hay alone are often energy and protein deficient. Add 4–6 lbs of alfalfa hay or a late-gestation concentrate (14% CP) to grass-hay diets in the last trimester. Avoid tall fescue pasture (endophyte risk). Maintain BCS 5–6 through gestation; obese mares (BCS 7+) have more dystocia and metabolic complications at foaling.
Lactating Mares
Lactation is the highest nutritional demand a mare ever faces — greater than late gestation, greater than heavy athletic work. Peak milk production (first 3 months) requires:
- DE: +69% above maintenance (approximately 28 Mcal/day for 1,100-lb mare)
- CP: 1,500–1,700 g/day
- Calcium: 57 g/day
Many mares cannot eat enough forage to meet this demand without losing significant body condition. A high-quality alfalfa-grass mix fed free choice, plus 6–8 lbs of a 14–16% CP performance concentrate, is a typical lactating mare program. Monitor BCS weekly; losing more than 0.5 BCS units per month indicates underfeeding.
Performance Horses
Athletic horses have elevated energy requirements but must have those calories delivered safely — without triggering colic, tying-up, or the behavioral excitability and gut disruption associated with high-starch diets. The modern approach to performance horse nutrition emphasizes:
- Forage first — Even hard-working horses should get minimum 1.5% body weight in forage. Cutting forage to feed more grain is counterproductive and ulcerogenic.
- Fat as an energy source — Rice bran, flaxseed, or vegetable oils are calorie-dense and non-insulinogenic. Add fat gradually (start at 1 cup/day, increase over 3–4 weeks to tolerance).
- Split grain meals — Never more than 4–5 lbs starch-containing concentrate per meal. If a 1,200-lb performance horse needs 14 lbs of grain, split into 3 meals of 4–5 lbs each.
- Gastric ulcer prevention — Performance horses have high ulcer rates (60–90% in Thoroughbred racehorses). Frequent forage access, pre-exercise hay, and avoiding long fasting periods are more important than any supplement for ulcer prevention.
- Electrolyte replacement — A horse sweating heavily during a 1-hour ride loses 5–10 liters of sweat containing significant sodium, chloride, and potassium. Replace with a balanced electrolyte product.
Senior Horses (20+ Years)
The aging equine digestive system loses efficiency. Dental wear, reduced digestive enzyme activity, and changes in hindgut microbiome composition all contribute to the classic senior horse challenge: maintaining weight on what seems like plenty of feed. Common issues:
- Dental problems — Worn, missing, or loose teeth impair chewing. Hay passes through incompletely chewed, reducing digestibility and causing choke risk. Senior horses with dental issues need dentistry (floating, extractions) and a switch to complete pelleted feeds or soaked hay cubes/chaff that do not require long-stemmed chewing.
- Reduced protein digestion — Older horses show reduced efficiency of protein digestion and increased protein requirement (up to 12–14% CP even at maintenance). High-quality protein sources with good lysine (alfalfa, soybean meal) are important.
- PPID (Pituitary Pars Intermedia Dysfunction / Equine Cushing's Disease) — Common in horses over 15 years; causes muscle wasting, cresty neck, laminitis, increased susceptibility to infection. Horses with PPID must be on low-NSC diets (under 12% NSC) to minimize laminitis risk. Pergolide medication (Prascend) should be discussed with your vet.
- EMS (Equine Metabolic Syndrome) — Insulin resistance, obesity (especially cresty neck), laminitis risk. Low-NSC diet, weight management, and exercise are cornerstones of management.
Commercial senior feeds (Purina Equine Senior, Nutrena SafeChoice Senior, Triple Crown Senior) are formulated specifically for older horses: higher fiber, higher protein, lower NSC, softer texture for soaking. Many senior horses do best fed senior feed 2–3 times daily as their primary ration rather than as a supplement to hay.
Body Condition Scoring: Your Daily Management Tool
The Henneke Body Condition Scoring (BCS) system (1–9 scale) provides an objective, standardized way to assess a horse's energy reserves. Score based on fat deposition at six anatomical regions: neck, withers, shoulder, ribs, loin, and tailhead.
| BCS | Description | Management Action |
|---|---|---|
| 1–2 | Emaciated to very thin; bones prominent | Immediate veterinary evaluation; gradual refeeding under vet guidance |
| 3–4 | Thin; ribs easily felt and often visible | Increase calorie intake; investigate for underlying disease (PPID, dental) |
| 5 | Moderate; ribs felt with slight pressure; neck, withers, shoulder smooth | Ideal for most adults; maintain current program |
| 6 | Moderately fleshy; ribs felt with slight fat cover; some cresty neck start | Monitor; reduce calorie intake if trend continues upward |
| 7 | Fleshy; ribs hard to feel; notable fat deposits on neck, behind shoulder | Reduce concentrate; increase exercise; evaluate for insulin resistance |
| 8–9 | Fat to obese; ribs essentially buried in fat; obvious cresty neck | Significant calorie restriction; veterinary metabolic workup; laminitis risk is high |
Target BCS for most horses: 4.5–6.0. Performance horses often do best at 5–5.5. Broodmares approaching foaling: 5.5–6.5 (slight reserve for early lactation). EMS and insulin-resistant horses: 4.5–5.0 strictly. Assess BCS monthly at minimum; weekly for horses in active management programs.
Common Nutrition-Related Health Problems
Laminitis
Inflammation of the laminar tissue connecting the hoof wall to the coffin bone. Dietary laminitis is triggered by excessive NSC intake (starch + sugars) causing insulin dysregulation, or by starch/fructan overload causing hindgut acidosis. Prevention: strict NSC management in at-risk horses, no spring grass access without muzzle or restriction, and avoiding high-grain, low-fiber diets. Once a horse has had laminitis, it is a managed condition for life — work with your vet and an equine nutritionist.
Colic
Abdominal pain in horses — the leading cause of premature death in adult horses in the US. Nutritional risk factors include: sudden feed changes, grain engorgement (excess starch flooding the hindgut), inadequate water intake, low-forage diets, and heavy sand intake in regions with sandy soils (sand colic). Prevention aligns with all the forage-first, slow-transition principles already discussed. Call your vet immediately if colic signs persist more than 30–60 minutes or worsen.
Equine Gastric Ulcer Syndrome (EGUS)
Estimated to affect 50–90% of performance horses and a significant proportion of recreational horses. Risk factors: high-starch diets, long periods without forage (overnight fasting, transport), NSAIDs (bute), stress, and intermittent feeding. Nutritional management: maximize forage access, feed hay before exercise, consider buffering agents (ranitidine, omeprazole — the latter is the only FDA-approved treatment), reduce starch intake, add alfalfa hay (its calcium and protein buffer gastric acid).
Developmental Orthopedic Disease (DOD)
An umbrella term for bone and joint growth problems in young horses: OCD, physitis, wobbler syndrome, and flexural deformities. Caused by a combination of genetic predisposition and nutritional imbalances — particularly excessive calorie intake (rapid growth rate), copper or zinc deficiency, and calcium-phosphorus imbalance. Avoid overfeeding young horses; maintain proper Cu:Zn ratios; balance Ca:P.
Tying-Up (PSSM and RER)
Two distinct muscle disorders with a common presentation — painful muscle cramping and reluctance to move during or after exercise. Polysaccharide Storage Myopathy (PSSM) is managed with a high-fat, low-starch diet (under 10% NSC) and consistent daily exercise. Recurrent Exertional Rhabdomyolysis (RER) is stress-related; benefits from consistent work routine, vitamin E, and fat-based energy sources to replace starch.
Regional and Seasonal Feeding Considerations
Winter Feeding
Cold temperatures increase maintenance energy requirements. A rough rule: for every 10°F below the horse's lower critical temperature (approximately 18°F for a healthy, well-acclimated horse with a full winter coat), energy needs increase by about 2.5%. A horse at 0°F ambient temperature needs approximately 20–25% more energy than at 50°F. Provide:
- Additional hay — the fermentation of fiber in the hindgut generates heat and is the most efficient way to keep horses warm
- Warm or tepid water — horses dramatically reduce water intake when water is close to freezing, sharply increasing colic risk; tank heaters are among the best investments a northern horse owner can make
- Shelter — reduces wind-chill energy demands
Spring Pasture Transition
The transition from dry hay to lush spring pasture should take 2–3 weeks minimum. Start with 30–60 minutes of pasture access per day in the first week, gradually increasing. High-risk horses (easy keepers, ponies, any prior laminitis) should wear grazing muzzles and may need to wait until pasture growth slows and sugar content drops (mid-late spring).
Summer Heat and Electrolytes
Hot, humid summers in the Southeast, Midwest, and mid-Atlantic require attention to heat stress and electrolyte depletion. Ensure shade and water at all times. Feed during cooler morning and evening hours. Reduce or eliminate exercise during heat advisories (Heat Index above 150°F combined temperature + humidity). Heavy sweaters (horses that sweat profusely) or horses in regular summer work need daily electrolyte supplementation.
Drought and Hay Shortages
Drought years (common in the West, Southern Plains, and intermittently across all regions) can create hay shortages and quality inconsistency. Strategies:
- Source hay from outside the drought region early — prices increase significantly by fall
- Supplement hay shortfalls with beet pulp, hay cubes, or complete feeds — do not cut below 1.5% body weight forage intake
- Test drought-stressed hay for nitrates — stressed grasses accumulate nitrates that can be toxic to horses
- Consider reducing herd size temporarily rather than underfeed retained horses
Cost of Feeding a Horse: Realistic Estimates by Region
| Cost Category | Northeast | Southeast | Midwest | Southwest/West |
|---|---|---|---|---|
| Hay (per ton, grass) | $350–$550 | $200–$350 | $180–$300 | $200–$450 |
| Daily hay cost (20 lbs) | $3.50–$5.50 | $2.00–$3.50 | $1.80–$3.00 | $2.00–$4.50 |
| Grain/concentrate (per month, 5 lb/day) | $45–$80 | $40–$70 | $35–$65 | $40–$75 |
| Salt block (per month) | $2–$4 | $2–$4 | $2–$4 | $2–$4 |
| Supplements (avg per month) | $20–$60 | $20–$50 | $20–$50 | $20–$60 |
| Total monthly feed cost (moderate work) | $170–$320 | $120–$240 | $100–$220 | $120–$280 |
Note: Horses with pasture access have significantly lower hay costs. Hay costs are highly variable year-to-year based on drought and production conditions. High-performance horses in heavy training may have monthly feed costs of $400–$700+ depending on concentrate quality and supplementation.
When to Call Your Equine Veterinarian
Many nutritional adjustments can be made independently using the principles in this guide. But some situations require professional veterinary and/or nutritionist involvement:
- Any horse that loses weight despite adequate-appearing feed — Rule out dental disease, PPID, parasites (especially in young horses), or GI disease
- Laminitis — active or suspected — An emergency. Call your vet and remove the horse from pasture immediately
- Tying-up (muscle stiffness, dark urine after exercise) — Stop exercise, call vet; myoglobinuria can cause kidney damage
- Colic persisting more than 30–60 minutes — Do not wait; equine colic can escalate to life-threatening surgical emergency within hours
- Choking (feed material at nostrils, repeated swallowing attempts) — Usually resolves with muscle relaxants administered by a vet; do not let obstruction persist more than 2–4 hours without veterinary intervention
- Foals failing to nurse or appearing weak — Mare milk and colostrum are life-critical in the first 24 hours; failure of passive transfer is an emergency
- Senior horse with sudden weight loss — PPID, dental disease, and internal neoplasia all need diagnostic workup
- Before designing a feeding program for any horse with a health condition — PPID, EMS, PSSM, chronic laminitis, and other conditions require individualized, vet-guided nutrition plans
Find a Large Animal Vet Near You
Getting your horse's nutrition right is the foundation of health, performance, and longevity. But even the best feeding program works better with a trusted equine veterinarian who knows your horses, your region, and your goals. From routine dental care that directly impacts hay utilization, to metabolic workups for the horse losing weight despite your best efforts, to emergency response when colic strikes at midnight — a relationship with a qualified large animal or equine vet is one of the best investments you can make for your horses.
FarmVetGuide helps horse owners across the US find qualified large animal and equine veterinarians in their area. Search by state and county, filter for mobile farm-call vets who come to you, find vets with equine-specific experience, and locate emergency-available practitioners near your barn.
Visit www.farmvetguide.com to find an equine vet near you today.
Frequently Asked Questions
How much hay should I feed my horse per day?
The starting point is at least 1.5–2% of the horse's body weight in forage daily on a dry matter basis. For a 1,100-lb horse, that is 16.5–22 lbs of hay per day. Horses at maintenance on good-quality pasture need less supplemental hay; horses in heavy work, lactating mares, and hard keepers may need 25–30+ lbs or supplemental concentrate calories. Never let a horse go more than 6 hours without forage access, and never cut below 1.5% body weight even when managing weight.
Do horses need grain every day?
Many horses — particularly easy-keeper adults at light work or pasture rest — do not need grain at all. A high-quality forage diet balanced with a vitamin-mineral supplement or ration balancer pellet (1–2 lbs/day) meets all nutrient requirements for these horses without the metabolic and digestive risks of grain feeding. Grain is indicated when forage alone cannot supply the calories needed — heavy performance horses, lactating mares, growing horses, seniors with poor dentition, and winter hard-keepers are the main categories.
Is alfalfa hay safe for horses?
Yes — alfalfa is an excellent and valuable forage for horses with elevated nutrient needs (lactating mares, growing horses, performance horses, underweight horses). The concerns about alfalfa (excess protein, high calcium) are overstated for most horses and only relevant if fed exclusively in large quantities to mature idle horses. Alfalfa-grass mixed hay is often the ideal forage for many horses, providing a balance of energy, protein, and minerals without the extremes of either pure alfalfa or poor-quality grass hay.
What supplements should every horse have?
At minimum: a plain white salt block (or loose salt) available free choice at all times. Beyond that, the "essentials" depend on the individual horse's diet and access. Horses without pasture access should have Vitamin E supplemented (1,000–2,000 IU/day of natural-source d-alpha-tocopherol). Horses in selenium-deficient regions need selenium supplementation (typically included in complete mineral supplements or feeds). Beyond these, identify specific deficiencies through forage testing before buying supplements — most horses on a properly formulated diet with good forage do not need a cart full of supplements.
How do I safely switch my horse's feed?
Always transition over a minimum of 7–14 days. For a hay change: mix old and new hay, starting at 75% old/25% new, progressing to 50/50, then 25/75, then 100% new over 10–14 days. For concentrate changes: add new product in small amounts while reducing the old, over 7–10 days. Rapid switches disrupt hindgut microbial populations and can cause colic, diarrhea, and laminitis in sensitive horses. If the horse shows loose manure or colic signs during any transition, slow down and spend more days at the current ratio.
What causes weight loss in horses that are eating normally?
Multiple conditions can cause weight loss despite adequate apparent intake: dental disease (the horse cannot chew effectively — feed passes through inadequately digested), PPID (equine Cushing's disease — accelerates muscle wasting through cortisol effects), heavy parasite burden (particularly in younger horses), chronic pain or stress (elevates cortisol and suppresses weight gain), inflammatory bowel disease or right dorsal colitis, liver disease, or simple calorie insufficiency in a high-demand horse (hard keeper, heavy work, cold environment). Any horse losing weight despite what seems like adequate feed warrants a veterinary examination and targeted diagnostics.
Is beet pulp good for horses?
Beet pulp is an excellent feed ingredient for horses and is often underutilized. It is a byproduct of sugar beet processing — the sugars have been extracted, leaving a highly digestible fiber that ferments beneficially in the hindgut. It is low in NSC (safe for metabolic/laminitic horses), moderate in energy, high in calcium, and highly palatable when soaked. Beet pulp helps add calories without starch loading, is useful for senior horses who need a grain alternative, and can dramatically improve hydration when fed soaked. Use unmolassed beet pulp (without added molasses) for horses with metabolic concerns. Soak for 15–30 minutes before feeding.