Silicon in Horse Feeds: Joint Health & Coat Quality

Why Silicon Matters in Your Horse's Diet

Silicon is one of those trace elements that rarely makes the headlines in equine nutrition, yet it plays a surprisingly important role in your horse's overall health. Found naturally in forages, grains, and certain supplements, silicon contributes to the structural integrity of connective tissues, bones, joints, and even your horse's coat and hooves.

While it hasn't received the same attention as minerals like calcium, phosphorus, or selenium, research over the past few decades has steadily revealed that silicon deserves a closer look — especially if you're managing a horse with joint concerns, poor hoof quality, or a dull coat.

In this article, we'll explore what silicon does in the horse's body, where it comes from in the diet, how much your horse needs, and how to ensure they're getting enough.

What Is Silicon and What Does It Do?

Silicon (Si) is the second most abundant element in the Earth's crust, and it occurs naturally in many feedstuffs as silica (silicon dioxide) or as orthosilicic acid — its bioavailable form. In the horse's body, silicon is concentrated in connective tissues, including cartilage, tendons, ligaments, bone, skin, hair, and hoof horn.

Silicon's Key Functions

• Collagen synthesis: Silicon is involved in the cross-linking of collagen and glycosaminoglycans (GAGs), the structural proteins that give connective tissues their strength and elasticity.
• Bone mineralisation: Research suggests silicon plays a role in the early stages of bone formation, helping to lay down the organic matrix upon which calcium and phosphorus are deposited.
• Cartilage maintenance: By supporting the production of proteoglycans and collagen within cartilage, silicon helps maintain the cushioning and shock-absorbing properties of joints.
• Hoof and coat integrity: The structural role of silicon extends to keratinised tissues — hooves, mane, tail, and coat — where adequate silicon helps maintain strength and quality.

In simple terms, silicon acts as a kind of biological scaffolding material. Without enough of it, the structures that rely on collagen and connective tissue can become weaker and less resilient.

Silicon and Joint Health in Horses

Joint health is a major concern for horse owners across every discipline. Whether you're managing an older horse with early arthritis, a sport horse under heavy workload, or a young growing horse building its skeletal framework, silicon has relevance.

How Silicon Supports Joints

Articular cartilage — the smooth, slippery tissue that lines the ends of bones within a joint — depends on a healthy matrix of collagen and proteoglycans. Silicon contributes to the synthesis and structural integrity of both.

Studies in other species (including humans and poultry) have shown that silicon supplementation can:

• Increase collagen concentration in bone and cartilage
• Improve the structural quality of connective tissue
• Support the body's natural repair mechanisms after joint stress

While large-scale equine-specific clinical trials on silicon are still limited, the biochemical pathways are well understood, and many equine nutritionists consider silicon an important supportive nutrient for joint health — particularly alongside better-studied joint supplements like glucosamine, chondroitin, hyaluronic acid, and MSM.

Silicon for Growing Horses

Young, rapidly growing horses are particularly interesting when it comes to silicon. During growth, the skeleton is being actively modelled and remodelled, and the demand for structural nutrients is high. Some research in young horses has indicated that silicon supplementation may support bone density and reduce the incidence of developmental orthopaedic conditions, though more research is needed to establish firm dose-response relationships.

If you're raising a young horse and want to ensure their mineral intake is balanced, analysing your horse's diet is a sensible first step. It helps identify not just silicon status but any broader mineral imbalances that could affect skeletal development.

Silicon and Coat Quality

A gleaming, healthy coat is one of the first things people notice about a well-cared-for horse — and one of the first things to deteriorate when nutrition is lacking. Silicon contributes to coat quality in several ways.

The Connection Between Silicon and Keratin

Hair (and hoof horn) are composed largely of keratin, a tough structural protein. Silicon is found in relatively high concentrations in keratinised tissues, and it appears to contribute to the strength, elasticity, and overall quality of hair.

Horse owners who have added bioavailable silicon to their horse's diet frequently report improvements in:

• Coat shine and texture — a smoother, glossier appearance
• Mane and tail quality — less breakage, improved growth
• Skin health — fewer flaky or dry patches

While coat quality is affected by many nutritional factors (protein, essential fatty acids, zinc, copper, biotin, and methionine all play roles), silicon is an often-overlooked piece of the puzzle.

Hoof Health Too

It's worth noting that the same keratinised tissue principles apply to hooves. Horses with poor hoof quality — thin walls, cracking, slow growth — may benefit from improved silicon intake alongside other hoof-supporting nutrients like biotin, zinc, and methionine. Silicon helps strengthen the structural bonds within the hoof wall, contributing to a tougher, more resilient hoof.

Dietary Sources of Silicon for Horses

The good news is that silicon is naturally present in many common feedstuffs. The challenge is that not all forms of silicon are equally bioavailable.

Natural Feed Sources

Grasses tend to accumulate silicon from the soil as they mature, which is why mature grass hay can be relatively high in total silicon. However, much of this silicon is locked up as phytolithic silica — essentially microscopic glass-like particles within the plant — which is poorly absorbed by the horse.

Fresh, young pasture generally provides silicon in more available forms than dried, mature hay.

Supplemental Sources

When dietary intake from forage and feed is insufficient, or when a horse has specific needs (joint support, hoof improvement, coat quality), supplemental silicon can be considered. Common supplemental forms include:

• Orthosilicic acid (OSA): The most bioavailable form. Often stabilised with choline (choline-stabilised orthosilicic acid, or ch-OSA) for better absorption. This is the form most commonly used in joint and coat supplements.
• Silicon dioxide (silica): Widely available but relatively poorly absorbed in its raw form.
• Diatomaceous earth: Contains silica but bioavailability is very low. Often marketed for other purposes (parasite control), its nutritional value as a silicon source is limited.
• Bamboo extract: A plant-based source of organic silicon, sometimes included in equine supplements.
• Nettle (Urtica dioica): A herb naturally high in silicon, sometimes used in herbal blends.

For meaningful nutritional impact, orthosilicic acid or stabilised forms are generally preferred due to their superior absorption.

How Much Silicon Does a Horse Need?

This is where things get a bit murky. Unlike minerals such as calcium, phosphorus, or selenium, there is no established NRC (National Research Council) requirement for silicon in horses. This is partly because outright silicon deficiency is rare in horses consuming a forage-based diet, and partly because research hasn't yet pinpointed an exact daily requirement.

However, some general guidelines from the research and practical experience suggest:

• Horses on good-quality pasture likely receive adequate silicon for basic needs.
• Horses on predominantly hay-based diets, especially older or very mature hay, may have lower bioavailable silicon intake.
• Horses with increased connective tissue demands — growing horses, performance horses, those recovering from injury, or those with poor hoof/coat quality — may benefit from supplementation.

Typical supplemental doses used in equine products range from 50 to 200 mg of bioavailable silicon per day, though this varies by product and form.

Signs Your Horse Might Benefit from More Silicon

Because there's no simple blood test for silicon status in horses, you'll typically look at indirect signs:

• Dull, lacklustre coat despite adequate protein, fat, and other mineral intake
• Slow hoof growth or poor hoof quality that doesn't fully respond to biotin and zinc
• Joint stiffness or early degenerative changes, particularly in performance horses
• Poor mane and tail quality — brittle, thin, or slow-growing hair
• Delayed healing of connective tissue injuries

None of these signs are unique to silicon insufficiency, which is why it's important to look at the whole diet rather than reaching for a single supplement. A comprehensive diet analysis can help you rule out other deficiencies first.

Silicon Safety and Toxicity

Silicon is generally considered very safe. Toxicity from dietary silicon in horses is essentially unheard of, partly because excess silicon is efficiently excreted through the kidneys. Horses that graze on high-silica pastures or consume silica-rich hays do not develop toxicity issues.

That said, as with any supplement, more is not necessarily better. Providing silicon within recommended supplemental ranges is sensible. There's no evidence that mega-dosing produces superior results.

One practical note: extremely high silica content in very mature or stemmy hays can contribute to increased tooth wear over a horse's lifetime, though this is a mechanical issue (abrasion from phytoliths) rather than a nutritional toxicity concern.

How to Incorporate Silicon Into Your Horse's Feeding Plan

Here's a practical approach to ensuring your horse gets adequate silicon:

Step 1: Start With Good Forage

Fresh pasture is the best natural source of bioavailable silicon. If your horse has access to quality grazing, they're likely getting a reasonable baseline. Horses on hay-only diets may benefit from supplementation.

Step 2: Review the Whole Diet

Before adding a silicon supplement, look at the bigger picture. Is your horse getting adequate protein, essential amino acids, omega-3 fatty acids, zinc, copper, and biotin? These all interact with coat, hoof, and joint health. Addressing broader nutritional gaps first often produces the most dramatic improvements.

Step 3: Choose a Bioavailable Supplement If Needed

If you decide supplementation is warranted, choose a product that provides silicon in a bioavailable form — orthosilicic acid or choline-stabilised orthosilicic acid are the gold standards. Follow the manufacturer's dosing guidelines.

Step 4: Be Patient

Connective tissue turnover is slow. It can take three to six months to see visible improvements in coat quality, hoof growth, or joint comfort from any nutritional change. Consistency is more important than dose.

Silicon in the Context of a Balanced Diet

It's tempting to focus on individual nutrients — especially when a particular one sounds promising — but the reality of equine nutrition is that everything works together. Silicon supports collagen, but collagen also needs vitamin C (which horses synthesise endogenously), copper, zinc, and adequate protein. Bones need silicon for their organic matrix, but they also need calcium, phosphorus, magnesium, and vitamin D.

The most effective approach is always to ensure the whole diet is balanced before fine-tuning individual trace elements. If you're unsure whether your horse's current feeding plan covers all the bases, consider using a tool to analyse your horse's diet and identify any gaps.

Key Takeaways

• Silicon is an important structural trace element involved in collagen synthesis, bone formation, cartilage maintenance, and the quality of hair, skin, and hooves.
• Joint health benefits come from silicon's role in maintaining cartilage and connective tissue integrity.
• Coat and hoof improvements are commonly reported when bioavailable silicon is added to the diet.
• Fresh pasture is the best natural source; hay provides silicon but in less available forms.
• Orthosilicic acid is the most bioavailable supplemental form.
• No established NRC requirement exists, but supplementation in the range of 50–200 mg/day of bioavailable silicon is commonly used.
• Safety is excellent — toxicity is essentially non-existent at normal dietary and supplemental levels.
• Always balance the whole diet first before focusing on individual trace elements.

Silicon may not be the most glamorous nutrient on the shelf, but for horses that need extra support for joints, hooves, or coat, it's well worth considering as part of a well-balanced feeding programme.