Nutrition mistakes we make with young horses

When raising a young horse, it’s easy to obsess over the size of the foal, the straightness of the legs, the condition of the coat, and, of course, how early they start looking ‘like a horse.’ But appearances can be misleading. The real foundation of a future athlete lies beneath the skin, in how the skeleton, cartilage, tendons, and joints develop during those first few years.

Unfortunately, well-meaning but misguided feeding practices – especially in Warmbloods and Thoroughbreds bred for performance – can set the stage for orthopaedic disease, joint problems, and early soundness issues. In this article, we examine the critical stages of musculoskeletal development, the impact of feeding on growth patterns, and where breeders and owners commonly go wrong.

1) Fast isn’t better: Understanding growth plate vulnerability

The long bones of the limbs grow at their ends, in regions called physes, or growth plates. These are zones of cartilage that gradually harden into bone (ossify) and close at different times. Some, like the lower cannon bone, close within a few months of age; others, like the pelvis and vertebrae, don’t fully mature until five to six years of age.

When a young horse grows too fast – whether due to genetics, overfeeding, or sudden dietary shifts – the growth plates are put under mechanical and metabolic stress, increasing the risk of:

• Angular limb deformities
• Osteochondrosis/osteochondritis dissecans
• Epiphysitis (inflammation of the growth plate)
• Joint swelling or pain

Key principle: Slow, steady, well-supported growth is preferable to large gains or early maturity. Bigger is not better – stronger and sounder is.

2) Calories vs. nutrients: The ‘fat but deficient’ foal

One of the most common mistakes is overfeeding energy (in the form of calories) while underfeeding essential nutrients. Young horses may appear well-covered and even fat, yet still suffer from subclinical deficiencies that impair skeletal development.

Common pitfalls:

• Feeding too much high-starch concentrate without balancing minerals.
• Relying on pasture quality alone during peak growth phases.
• Assuming a mare’s milk or basic creep feed is enough without analysis.

This imbalance can lead to rapid weight gain without corresponding increases in bone density or joint resilience, tipping the foal into a state where soft tissues and joints are overstressed.

3) The critical role of minerals in bone development

Certain minerals are non-negotiable for healthy growth, and their balance matters as much as their presence.

Calcium and phosphorus:

• The foundation of bone formation.
• Ideal ratio: 1.2–2:1 Calcium : Phosphorus.
• Imbalances (especially excess phosphorus, e.g., from bran or cereal-based diets) are linked to skeletal abnormalities.

Copper and zinc:

• Copper: essential for collagen formation and cartilage maturation.
• Zinc: key in growth, immune function, and hoof/hair integrity.
• Deficiencies are strongly associated with osteochondrosis in foals and young horses.

Magnesium:

• Plays a role in bone strength and supports enzyme systems that regulate growth.

Important: Even if total mineral content appears adequate, interactions between minerals (e.g. excess iron interfering with zinc and copper absorption) can create secondary deficiencies. Many diets – especially in South Africa – are high in iron and low in copper/zinc.

4) Feeding phases of the young horse: birth to three years

Birth to six months (nursing foal):

• Mare’s milk supplies much of the energy, protein, and calcium required.
• But milk is low in copper, zinc, and iron, so towards six months of age foals still need access to a balanced creep feed or supplement.
• Foals on poor soil/pasture are especially vulnerable to early deficiencies.

6–12 months (weaning):

• Rapid growth phase.
• Nutrient demand peaks, particularly for protein and trace minerals.
• Weaning is a stressor, so supporting gut health and immune function is vital.
• Avoid sudden increases in starch or new concentrates.

12–24 months:

• Growth slows but still active.
• Skeleton continues to mature, and this is a critical time for osteochondritis/osteochondritis dissecans (OCD) to emerge.
• Excess energy without mineral support is a major risk.

Two to three years (pre-training/early under-saddle):

• Musculoskeletal stress increases if youngsters are lunged and ridden.
• Nutritional needs now include joint support, muscle recovery, and topline development.
• Prioritise quality protein (especially lysine, threonine), balanced minerals, and calories from fibre/fat, not just grain.

Starch overload: Why ‘show condition’ can backfire

Young horses are often fed like adults in training, with starch-heavy concentrate to create a filled-out topline and shiny coat. But high-starch meals (especially >1.5–2 g/kg BW per meal) are strongly linked to:

• Hindgut acidosis
• Disrupted gut flora
• Increased risk of osteochrondrosis lesions
• Increased excitability or stress-related behaviours

Instead:

• Base energy on high-quality forage, beet pulp, and oils
• Use low-non-structural carbohydrate (NSC) feeds designed for growth, with added amino acids.
• Choose slow, steady development over bulked-up fast gain.

6) When to intervene: Warning signs of nutrition-related growth problems

Watch for:

• Uneven or asymmetrical limb growth.
• Swollen joints (particularly stifle, hock, fetlock).
• Foals or weanlings that are fat but lack muscle.
• Sudden growth spurts during dietary changes.
• Poor hoof quality or growth rings that suggest nutritional stress.

7) Top mistakes to avoid

• Feeding for condition instead of development.
• Assuming a chubby foal is a healthy one.
• Using adult performance feeds for growing youngsters.
• Skipping forage – roughage is essential from an early age.
• Neglecting to supplement copper and zinc in iron-rich soils.
• Making big ration changes during growth spurts.
• Failing to involve your vet, nutritionist, and farrier in a shared plan.

8) What does a well-fed young horse look like?

• Moderate body condition (BCS 5–6/9) – not ‘show fat’.
• Strong, symmetrical limbs and steady topline development.
• Calm behaviour and healthy hoof growth.
• Clean joints and smooth growth plates.
• Energy to move, but not sharp or stressed.
• Growth that is predictable, not sudden.

Feeding for soundness, not size

Whether you’re raising a Warmblood prospect for dressage or a Thoroughbred destined for sport, your feeding choices today lay the structural foundation for tomorrow’s success or struggle. Nutrition won’t override genetics or fix bad conformation, but it can protect, preserve, and support the growth potential a foal was born with.

Instead of chasing early maturity, feed for long-term durability, symmetry, and soft tissue integrity. Your future vet bills – and your future athlete – will thank you.