Feeding Horses: Forage, Grain, and Body Condition

Proper nutrition is the cornerstone of equine health and performance. Horses are herbivores with a digestive system designed for continuous grazing on fibrous forages. Any deviation from this natural diet must be carefully managed to avoid metabolic disorders, colic, or weight issues. This comprehensive guide, grounded in veterinary science and international guidelines, covers the three pillars of equine feeding: a forage-first approach, the judicious use of grain concentrates, and the systematic evaluation of body condition. Whether you are a new horse owner or an experienced equestrian, understanding these principles will help you maintain your horse in optimal health, whether in North America, Europe, Australia, or Canada.

Quick Q&A

Question: How much forage should a horse eat per day?
Answer: A horse should consume approximately 1.5% to 2% of its body weight in forage (hay or pasture) daily. For a 500 kg (1100 lb) horse, that equates to 7.5 to 10 kg (16.5 to 22 lb) of forage. Adjust based on workload, age, and body condition.

The Forage-First Philosophy

Forage (hay, pasture, haylage) should be the foundation of every horse’s diet. The horse’s gastrointestinal tract evolved for near-constant consumption of high-fibre plant material. The American Association of Equine Practitioners (AAEP) strongly recommends that horses receive at least 1.5% of their body weight in forage daily [1]. This guideline is echoed by the Merck Veterinary Manual, which states that forage should make up the majority of the ration [2].

Types of Forage

The choice of forage depends on regional availability, season, and the horse’s needs. Common types include:

• Grass hay (timothy, orchard grass, brome): Moderate in protein and energy, ideal for most adult horses.
• Legume hay (alfalfa, clover): Higher in protein, calcium, and energy; useful for growing, lactating, or hard-working horses but can be too rich for easy keepers.
• Mixed hay: A blend of grasses and legumes, offering balanced nutrition.
• Pasture: Fresh grazing provides high moisture, vitamins, and low starch if managed properly. However, spring grass can be dangerously high in non-structural carbohydrates (NSC) for horses prone to laminitis or equine metabolic syndrome (EMS) [3].

Feeding Management

Forage should be provided free-choice or in multiple small meals to mimic natural feeding behaviour. Slow feeders can extend eating time and reduce waste. In Australia, where drought conditions are common, owners may need to supplement with hay cubes or chopped forages. According to the CVMA (Canadian Veterinary Medical Association), horses should never go more than 4 hours without forage to reduce the risk of gastric ulcers and behavioural problems [4].

Concentrates and Grain Feeding

Concentrates (grains and commercial feeds) are energy-dense supplements used when forage alone does not meet a horse’s calorie, protein, or mineral needs. They are necessary for performance horses, pregnant or lactating mares, weanlings, and occasionally for underweight seniors. However, overfeeding grain is a leading cause of colic, laminitis, and tying-up [5].

Types of Concentrates

• Oats: Lower in starch and energy compared to corn or barley; a traditional choice with good palatability.
• Corn: Higher in starch, should be processed (cracked or steam-flaked) to improve digestibility.
• Barley: Common in European feeding; often rolled or boiled.
• Commercial pelleted or textured feeds: Formulated to provide balanced vitamins and minerals; often labelled for specific life stages or conditions (e.g., low-starch feeds for metabolic issues).

Guidelines for Feeding Grain

The AAEP advises that grain-based concentrates should never exceed 0.5% of body weight per meal (e.g., 2.5 kg for a 500 kg horse) to reduce the risk of starch overload in the hindgut [1]. Total daily grain intake should not exceed 1% of body weight unless under veterinary guidance. Introduce grain gradually over 7-10 days. Always feed by weight, not by volume, as scoop sizes vary.

In the UK and Europe, the FVE (Federation of Veterinarians of Europe) similarly cautions against high-starch feeding, promoting the use of fibre-based balancers and oil supplements as safer alternatives [6].

Body Condition Scoring (BCS)

Body condition scoring is a systematic method to assess a horse’s fat cover. The most widely used system is the Henneke scale from 1 (emaciated) to 9 (obese), adopted by the AAEP and the Merck Veterinary Manual [2][7]. Regular BCS evaluation allows owners to adjust feeding and exercise to maintain an ideal score of 5 to 6 (moderate to moderately fleshy).

How to Score (Henneke Scale)

Scoring involves palpation of six key areas: neck, withers, ribs, loin, tailhead, and shoulder. A horse with a BCS of 5 has ribs that can be easily felt but not seen, a flat back, and a slight crease along the loin. At BCS 6, the ribs are harder to feel and a positive crease develops. Horses above BCS 7 are at increased risk for laminitis, insulin resistance, and joint stress [8].

Adjusting Diet Based on BCS

• Underweight (BCS 1-4): Increase forage quantity first, then add a high-fat supplement or a balanced grain concentrate. Rule out dental disease, parasites, or medical conditions like pituitary pars intermedia dysfunction (PPID).
• Overweight (BCS 7-9): Restrict forage (but never below 1.5% body weight), replace grain with a low-NSC balancer, and increase exercise. Consult a veterinarian or equine nutritionist. The Royal Society for the Prevention of Cruelty to Animals (RSPCA) in Australia emphasises that weight management is critical for welfare [9].

Water and Salt Requirements

Water is the most essential nutrient. A typical horse drinks 20 to 40 litres (5 to 10 gallons) per day, though this increases in hot weather, during lactation, or with heavy work. Access to clean, fresh water must be continuous. In freezing climates (Canada, northern USA), owners should use heated buckets to prevent ice.

Salt (sodium chloride) is equally vital. Horses lose electrolytes through sweat and require a steady supply. Provide free-choice white salt blocks (plain or iodized). For working horses, especially during summer, additional electrolytes may be mixed in feed. The AVA (Australian Veterinary Association) warns that horses in humid climates are at higher risk of dehydration and electrolyte imbalance [10].

Regional Considerations

• In drought-prone areas like parts of Australia and the western US, water quality (salinity, sulphate content) can affect intake. Regularly test well water.
• In Europe, many horses are stabled with automatic waterers; these should be checked daily to ensure function and cleanliness.

Special Populations and Metabolic Conditions

Horses with metabolic disorders such as EMS, PPID (Cushing’s disease), or polysaccharide storage myopathy (PSSM) require tailored diets. The AAEP Metabolic Syndrome guidelines recommend low-NSC diets (less than 10-12% NSC) and careful forage analysis [11]. For horses with PPID, consistent feed schedules and avoidance of high-sugar treats are important. Geriatric horses may need complete feeds or soaked hay pellets to compensate for poor dentition. In all cases, work with a veterinarian and an equine nutritionist to design a feeding plan.

Regional and Veterinary Guidelines

Equine feeding practices vary internationally, but core principles remain consistent. The AAEP (USA), CVMA (Canada), AVA (Australia), and FVE (Europe) all advocate for:

• Forage-first feeding (minimum 1.5% body weight daily).
• Careful use of concentrates, with meal sizes limited to reduce starch overload.
• Regular body condition scoring (target BCS 5-6).
• Unlimited access to clean water and free-choice salt.

In the UK, the British Equine Veterinary Association (BEVA) provides similar guidance. The European Food Safety Authority (EFSA) has also issued opinions on equine feed safety, stressing the need to monitor mycotoxins in forages [12]. These consensus guidelines are the bedrock of responsible horse ownership.

Conclusion

Feeding a horse correctly requires understanding its evolutionary biology as a grazing herbivore. Prioritise high-quality forage, supplement with grain only when necessary, and assess body condition regularly. Ensure constant access to water and salt. Whether you follow the AAEP’s recommendations in the United States, the CVMA’s guidance in Canada, or the AVA’s advice in Australia, the fundamentals are the same. Always consult your veterinarian or veterinary surgeon before making significant dietary changes, especially for horses with health conditions. A well-fed horse is a happy partner.

References

[1] American Association of Equine Practitioners (AAEP). AAEP Guidelines for Feeding Horses. Available from: aaep.org.

[2] Merck Veterinary Manual. Nutrition: Feeding Horses. merckvetmanual.com.

[3] Kentucky Equine Research (KER). Pasture Management and Nutrition. ker.com.

[4] Canadian Veterinary Medical Association (CVMA). Equine Nutrition Position Statement. canadianveterinarians.net.

[5] The Horse (veterinary-reviewed). Grain Overload and Colic. thehorse.com.

[6] Federation of Veterinarians of Europe (FVE). FVE Position on Equine Feeding. fve.org.

[7] Henneke, D. R., et al. (1983). A body condition scoring system for horses. Equine Veterinary Journal, 15(4), 371-372.

[8] American Association of Equine Practitioners (AAEP). Body Condition Scoring Brochure. aaep.org.

[9] Royal Society for the Prevention of Cruelty to Animals (RSPCA) Australia. Horse Nutrition and Weight Management. rspca.org.au.

[10] Australian Veterinary Association (AVA). Equine Health and Welfare Guidelines. ava.com.au.

[11] AAEP Equine Metabolic Syndrome Guidelines. (2021). Consensus Statement on EMS. aaep.org.

[12] European Food Safety Authority (EFSA). (2017). Scientific Opinion on the safety and efficacy of feed for horses. efsa.europa.eu.