Are we getting it right?

For decades, the default sporthorse ration looked something like this: two big buckets of concentrate, a slice or two of hay, electrolytes on hot days, and maybe oil ‘for shine.’ It worked, until it didn’t. Today’s competition horses jump higher, move bigger, travel more, and live more intensively managed lives than ever before. Meanwhile, the science on equine gastrointestinal physiology and metabolic health has exploded, revealing just how mismatched many traditional feeding systems are to the horse’s biology.

This article unpacks where we’re going wrong (hello, starch overload), what a forage-first, fibre- and fat-fuelled programme looks like, and how to individualise performance nutrition without compromising gut health.

1) From ‘hard feed equals energy’ to fuelling the right energy system

Not all ‘energy’ is created equal. The source and timing of calories should reflect the job the horse has to do.

The simplified model

• Aerobic work (dressage, most flatwork): Best supported by fats and fermentable fibre (e.g., beet pulp, soy hulls) that provide slow-release energy without large glucose/insulin spikes.
• Anaerobic bursts (jump-offs, short, intense efforts): Can utilise starch and sugars effectively, but the amounts and meal size matter for gut and metabolic safety.

Key idea: Most sporthorses (even jumpers and eventers) spend the majority of their training time in the aerobic zone. Yet their diets are often built around large, starch-heavy meals designed for brief periods of anaerobic activity.

2) The starch problem: ulcers, acidosis, and behaviour

High-starch meals (common in traditional mixes and sweet feeds) can:

• Overflow the small intestine’s capacity to digest starch, sending starch into the hindgut where it ferments rapidly, leading to hindgut acidosis, microbial disruption, gas, and laminitis risk.
• Increase gastric acidity (especially when fed in large, infrequent meals without adequate forage), contributing to squamous and glandular ulcers.
• Spike glucose and insulin, which can worsen metabolic instability and muscle disorders (e.g., Polysaccharide Storage Myopathies, Recurrent Exertional Rhabdomyolysis in susceptible horses).

Practical limits most experts now recommend are:

• Total starch per meal: Keep ≤1 g/kg bodyweight for ulcer-prone or sensitive horses (that’s ≤500 g for a 500 kg horse). More liberal upper limits of 1–2 g/kg of body weight are sometimes cited; however, staying on the lower end is generally safer for most.
• Total concentrate per meal: Rarely more than two kg (and often far less), with many horses thriving on multiple small meals or even no traditional grain at all.

3) Forage-first isn’t just a slogan

Horses are designed to trickle-feed fibre for 16 plus hours a day. Saliva (a powerful buffer) only flows when they chew. This means that long gaps without forage and chewing lead to acid bathing the stomach lining resulting in tissue damage and ulcer formation.

Targets to hit:

• Forage intake of 1.5–2% of bodyweight/day (dry matter (DM)) for most sporthorses (that’s 7.5–10 kg DM for a 500 kg horse; or approximately 9–12 kg ‘as fed’ hay depending on moisture).
• No gaps without access to forage.
• Slow feeders/small-holed nets to extend eating time for stabled horses.
• For easy keepers, swap to lower ‘non-structural carbohydrate’ (NSC), higher-structural-fibre forage rather than reducing the amount of forage.

4) Fat and fibre as performance fuel

Replacing a chunk of starch calories with oil and super fibres (beet pulp, soy hulls, lupin hulls) improves metabolic stability and gut health.

Benefits of a higher-fat, higher-fibre approach:

• Reduced post-prandial (after eating) glucose/insulin peaks.
• Lower excitability in some horses versus high-starch diets

How much fat?

Up to 0.8–1ml/kg of BW per day (≈ 400–500 ml for a 500 kg horse) is commonly used in high-performance horses, introduced gradually over three to four weeks to allow for metabolic adaptation.

5) Protein quality over protein quantity

Many rations oversupply crude protein but underdeliver key amino acids, especially lysine, threonine, and methionine, which are the true building blocks for topline, muscle repair, and hoof quality. [Pull these three amino acids – lysine, threonine and methionine from the diagram I’ve sent so they all look the same]

Therefore, we should:

• Aim for balanced amino acid profiles, especially in young, growing, or heavily training horses.
• Consider top-dressing with targeted amino acids rather than indiscriminately increasing total protein (which can increase urea production, stall ammonia levels, and dehydration risk).

6) Micronutrients: the silent performance killers

Common forage-only or ‘just add a bit of grain’ diets are frequently deficient in copper, zinc, selenium, vitamin E, and sometimes sodium (yes – plain salt is still underrated).

• Salt:Most sporthorses require at least 30–50 g/day of sodium chloride (NaCl), with higher amounts needed in hot climates or during heavy sweating conditions.
• Electrolytes: Use complete, balanced electrolyte mixes (not just salt) after sweat losses, ideally in a mash to support rehydration.
• Vitamin E: Horses on limited pasture often need supplemental natural vitamin E (d-α-tocopherol), particularly those on high-fat diets or in heavy work.
• Trace minerals: Zinc and copper are crucial for hoof and skin integrity; iron is rarely deficient (and often oversupplied).

7) Ulcers: feeding to prevent

Given the high prevalence of Equine Gastric Ulcer Syndrome (EGUS) in sporthorses, management-as-nutrition is non-negotiable. This involves:

• Forage before work and travel (a small haynet 30–60 minutes prior) to create a fibrous ‘mat’ that buffers acid.
• Multiple small concentrate meals rather than one or two large ones.
• Consider buffering strategies (e.g., alfalfa, certain marine-derived buffers) for horses with a history of ulcers, alongside veterinary treatment when needed.
• Routine, turnout, and social contact directly influence stress hormones, which in turn alter gut motility and acid exposure.

8) Periodising the ration

Just as you adjust training blocks, adjust the diet:

• Base phase/off-season: Emphasise forage, fibre, micronutrient balance, and maintaining an ideal body condition score (BCS 5–6/9 for most disciplines).
• Build/competition phase: Increase total digestible energy through fat and/or moderate starch, ensure high-quality amino acids, and fine-tune electrolytes.
• Recovery blocks: Support antioxidants (vitamin E), omega-3s, and protein quality, while ensuring gut health after travel/competition stress.

9) Discipline snapshots (very broad strokes)

Dressage (medium to Grand Prix):

• Mostly aerobic, so a fibre and fat base is important. Moderate starch can be included if temperament allows..
• Focus on muscle recovery, micronutrients and ulcer prevention.

Showjumping:

• Aerobic base with anaerobic spikes, making fibre and fat the ideal foundation, with carefully portioned starch for sharpness if needed.
• Electrolytes, gut support for travel, and regular body condition and topline monitoring all necessary.

Eventing:

• Phase-dependent: Cross-country demands favour glycogen management and electrolytes; flatwork phases are largely aerobic, so fibre and fat can dominate.
• Hydration and recovery nutrition are critical.

10) Quick audit: Are you feeding the modern way?

Tick what’s true for your current program:

• Forage is the foundation: ≥1.5–2% of BW per day, minimal gaps without fibre
• Total starch per meal is capped (ideally ≤1 g/kg of BW for sensitive horses)
• Oil/fat and fermentable fibre provide slow-release energy for most work
• Ration includes a balanced vitamin and mineral source (not just ‘a bit of mix’)
• Electrolytes are matched to sweat losses, not guessed
• Amino acids (lysine, threonine, methionine) are addressed, not just crude protein
• Diet is periodised across base, build, peak, and recovery phases
• Ulcer prevention is baked into management (forage-before-work, routine, turnout)
• You can justify every scoop in the bucket with a clear physiological reason for its presence

Bottom line: Performance starts with physiology

You can’t out-supplement a biologically inappropriate feeding system. The modern sporthorse needs forage-first, fibre- and fat-forward diets tailored to their workload, temperament, and gut, not just their discipline. Starch has its place, but not at the expense of the microbiome, stomach lining, or long-term soundness.

Feed the athlete, while respecting the herbivore.