Horse Feed & Forage Calculator

Horse Feeding Guide

What do I need to know about The 2.5% Rule?

Total daily intake (forage + concentrates): typically 2-2.5% of body weight by dry matter. A 500kg horse: needs approximately 10-12.5kg dry matter per day. Most should be forage — minimum 1.5% bodyweight in forage (7.5kg for 500kg horse). Horses evolved to graze 16-18 hours per day. Long feeding gaps (more than 4 hours) cause ulcers, stereotypies (crib-biting, weaving), and digestive issues. Ad lib forage is ideal where laminitis/obesity not a concern. For overweight horses: soak hay for around 12 hours before feeding, which reduces its sugar content while still providing the fibre needed for healthy digestion.

What's the key thing to understand about Forage Types?

Hay: traditional dried grass. Quality varies enormously. Should be sweet-smelling, green-brown, free of dust and mould. Late-cut hay: lower nutrition (better for easy keepers and laminitics). Early-cut: higher protein and sugar (for hard-working horses or thin ones). Haylage: partially dried, ensiled grass. Higher moisture (35-50%). Lower dust (good for respiratory issues). Higher energy. Open bale must be used within 5-7 days. Straw: bedding-grade can be fed sparingly to good doers as a low-calorie forage supplement, though it shouldn't replace proper hay as the main fibre source.

What's the key thing to understand about Laminitis Prevention?

Laminitis: inflammation of the laminae in the hoof. Extremely painful, often catastrophic. Major triggers: high sugar/starch intake (spring/autumn grass, cereal-based concentrates). Obesity. Equine Metabolic Syndrome (EMS) — insulin resistance. PPID (Cushing's disease) in older horses. High-risk breeds: native ponies (Welsh, Shetland, New Forest, Dartmoor, Exmoor). Cobs. Iberian breeds. Prevention: restrict grass access (track systems, grazing muzzles, dry lot in spring/autumn). Maintain ideal body condition year-round, since overweight horses and ponies of these predisposed breeds are at significantly higher risk of a laminitis episode.

What should I know about Concentrates?

Concentrates: cereal-based or fibre-based hard feeds. Used to supplement when forage cannot meet energy requirements. Light work: usually no concentrates needed if good forage. Moderate work: 0.5-1.5kg/day depending on horse. Heavy work: 2-4kg/day, split into 2-3 meals (never more than 2kg per meal — small stomach). Types: oats, barley, maize (cereals — high starch, hot). Sugar beet (high energy, slow release, soaked). Linseed (high oil, good for shine and weight gain). Balancers: low-calorie nutrient supplements that provide vitamins and minerals without the extra calories of a full concentrate feed, useful for good-doer horses that don't need extra energy.

Why Can't Horses Safely Skip Meals the Way Some Other Animals Can?

Horses are hindgut fermenters with a stomach and digestive system evolved for near-continuous small-scale grazing — roughly 16-18 hours per day in a natural setting — rather than for a small number of large, widely spaced meals the way many predator or omnivore species tolerate. A horse's stomach continuously produces acid regardless of whether food is present, which means extended gaps without forage (commonly more than about 4-6 hours) significantly increase the risk of gastric ulcers, a condition estimated to affect a very large proportion of performance and stabled horses. This is the core physiological reason equine feeding guidance emphasises constant or near-constant access to forage (hay or pasture) as the foundation of the diet, with concentrated feed treated as a smaller supplementary addition, rather than structuring a horse's diet around a small number of larger daily meals the way it might be done for a dog or human.

How Does Body Condition Scoring Guide Feed Adjustment for Horses?

Body condition scoring (commonly a 1-9 Henneke scale in the US or a 1-5 scale more common in the UK) assesses fat coverage at specific points on the horse's body — over the ribs, along the neck crest, around the tailhead, and behind the shoulder — providing a standardised way to judge whether a horse is receiving appropriate total feed intake independent of breed or frame size, since horses vary considerably in natural body shape. A horse scoring toward the thinner end of the scale generally needs increased forage or concentrate intake, while one scoring toward the heavier end needs reduced concentrate intake and, often, increased turnout or exercise rather than reduced forage, since forage restriction below adequate levels risks the gastric and behavioural problems associated with insufficient near-continuous feeding. Regular body condition scoring, ideally monthly, allows feed adjustments to be made gradually and specifically to the individual horse rather than relying solely on generic feed-amount guidelines based on bodyweight alone.

What should I know about Recognizing Colic Risk Factors Related to Feeding?

Colic — a general term for abdominal pain in horses — is strongly linked to feeding management, and several well-established risk factors are worth understanding for prevention. Sudden changes in feed type or amount, rather than gradual transitions over 7-10+ days, disrupt the gut's microbial balance and are a recognized colic trigger. Feeding large grain meals infrequently, rather than smaller, more frequent meals, increases risk because horses are designed to graze continuously in small amounts rather than eat large discrete meals. Limited turnout and reduced forage intake, along with inadequate access to fresh water (especially in cold weather when horses may drink less), are also established contributing factors. Because colic can range from mild to life-threatening quickly, consistent feeding routines and gradual dietary changes are considered some of the most effective, low-cost preventive measures available to horse owners.

Worked Example: Daily Forage for a 500kg Horse

Using the standard 2.5% of bodyweight guideline for total daily feed intake (forage plus any concentrates), a 500kg horse needs roughly 12.5kg of feed per day on a dry matter basis. If that horse is in light work and forage alone meets its needs, the full 12.5kg would come from hay or haylage. Because hay is not 100% dry matter — it typically contains some residual moisture — 12.5kg of dry matter might require around 13.5–14kg of hay as fed, to be weighed out and ideally split across at least three to four feeds through the day rather than given as one or two large meals, in line with how horses naturally graze almost continuously.

What should I know about Forage-to-Concentrate Ratios by Workload?

Even horses in hard work are generally recommended to receive forage making up a substantial share of the diet — a bare minimum of around 1.5% of bodyweight as forage is widely recommended by equine nutritionists, even when a large amount of concentrate feed is also being given, because the horse's digestive system is adapted to a near-continuous supply of fibre and restricting forage too much raises the risk of digestive upset, including colic and gastric ulcers. Sudden changes to either forage type or concentrate amount are a recognised risk factor for colic, which is why any dietary change — switching hay batches, introducing a new feed, or increasing workload and feed together — is generally recommended to happen gradually over 7 to 10 days rather than all at once, giving the horse's gut microbiome time to adjust. Clean, fresh water should also be available at all times alongside any feeding plan, since adequate water intake is essential for both digestion of fibrous forage and for reducing impaction colic risk, particularly when a horse's diet includes drier hay rather than fresh grass.

What should I know about Feeding Around Exercise?

Horses are generally recommended to have an empty-ish stomach and not be fed a large hard feed immediately before strenuous exercise, since a full stomach can press on the diaphragm and interfere with breathing during intense work, and digestion diverts blood flow away from working muscles. A common guideline is to allow at least an hour, and ideally longer, between a hard feed and strenuous exercise, though small amounts of forage are generally fine much closer to exercise since forage digests differently and more slowly than concentrated feed. After exercise, horses are typically allowed to cool down and their breathing to return to normal before being given a full feed, to avoid feeding a horse that's still breathing hard from work.