Horses are designed to graze and trickle-feed throughout the day, relying on fibre to keep their digestive system healthy and their energy levels steady. While hay and grass remain the backbone of any good equine diet, there’s now a category of feed ingredients known as “super fibres” that provide highly digestible energy without the risks associated with high starch diets.

In the UK, two of the best-known super fibres are soya hulls and unmolassed sugar beet pulp. These ingredients are excellent for condition, gut health, and sustained energy — and they can be especially helpful for older horses, performance horses, and those needing safe calorie boosts.

Soya Hulls – More Than Just Fibre

There’s a lot of confusion about soya as an ingredient, partly because it comes in several forms, each with different nutritional properties.

• Soybean meal is a concentrated source of high-quality protein and essential amino acids — particularly lysine — making it valuable for muscle development and repair.
• Soya oil contains no protein or fibre but is an excellent source of fat and slow-release energy.
• Soya hulls, however, are the fibrous outer coating of the soya bean. They contain very little protein, oil, or starch, but are a superb source of highly digestible fibre.

In horse feeds like Rowen Barbary ReadyFibre Mash, soya hulls are included to support hindgut health. Providing a variety of fibre sources in a diet helps increase both the diversity and stability of the horse’s gut microbes, which plays a huge role in digestion, immunity, and even behaviour.

From a safety perspective, it’s worth noting that the genetically modified (GM) soya used in animal feed is subject to strict safety testing in the UK and other countries. These tests look at allergenic potential, toxicity, nutritional profile, and environmental effects. Research to date finds GM soya safe for the vast majority of humans and animals.

Concerns about compounds like phytoestrogens are often misplaced — these are naturally present in many plants, including alfalfa, linseed, and even vegetables like broccoli and cauliflower. Any adverse effects seen in research occur at extremely high levels that horses simply wouldn’t consume in a normal diet. True allergies in horses are rare and can only be triggered by proteins — so ingredients like soya oil (no protein) or soya hulls (very low protein) are far less likely to cause an issue.

The key takeaway? Unless your individual horse has a proven sensitivity, soya hulls can be a safe, beneficial, and highly digestible part of a fibre-based diet.

Sugar Beet Pulp – The Soluble Fibre Star

Unmolassed sugar beet pulp is another firm favourite in UK feed rooms, and for good reason:

• Rich in soluble, fermentable fibre – Provides slow-release energy through microbial fermentation in the hindgut.
• Low sugar despite its name – Unmolassed beet pulp is very low in non-structural carbohydrates, making it suitable for laminitics and other sugar-sensitive horses.
• Easy to chew and digest – Soaked beet pulp is perfect for older horses, those with missing teeth, or fussy feeders.
• Non-heating calories – Supports weight gain or maintenance without causing fizzy behaviour.

Other Beneficial Fibre Sources in UK Diets

While soya hulls and beet pulp are standout super fibres, variety is vital for gut health. Other important fibre sources include:

• Forage (Grass, Hay, Haylage) – The foundation of the diet; aim for at least 1.5% of bodyweight in dry forage daily. Haylage can help dust-sensitive horses.
• Alfalfa – A nutrient-rich legume that provides quality protein, calcium, and buffering properties for the stomach.
• Straw – Low-calorie bulk for good-doers; best mixed with other forages to avoid digestive issues.
• Fibre Cubes & Chaffs – Convenient ways to feed a mix of fibre sources, often blending grass, alfalfa, beet pulp, and soya hulls.

Final Thoughts

Super fibres like soya hulls and sugar beet pulp tick all the boxes for a safe, effective, and gut-friendly energy source. They provide more digestible energy than hay, are low in sugar and starch, and help maintain a healthy microbial population in the hindgut.

While there’s a lot of noise online about soya, the science — and decades of safe use — show that soya hulls are a safe and beneficial option for most horses. As with any feed, the golden rule is to watch how your own horse responds, and choose the mix of fibre sources that keeps them healthy, happy, and performing at their best.