Want a healthy, fit and contented horse? Then everything starts with fibre. In this series Maartje explains why, in short episodes on digestion, forage, chewing and behaviour.

Short answer

Fibre is the foundation of a horse’s diet because the equine digestive system is built for it. Bacteria in the caecum and large intestine ferment fibre into volatile fatty acids, a source of slow-release energy. Fibre-rich forage also creates chewing time and saliva, which protect the stomach, and keeps a horse occupied for hours.

Why does everything start with fibre?

A horse is a grazer. In a natural setting it spends up to eighteen hours a day taking in fibre-rich forage. The digestive system matches that pattern: a relatively small stomach, a short small intestine and a large hindgut full of bacteria that ferment fibre.

That order also tells you how to build a ration. Forage is the starting point. Concentrate is what you add where forage does not cover the requirement – not the other way round. As a guideline, feed a minimum of 1.5% of bodyweight in dry matter from forage per day. For a 600 kg horse that is at least 9 kg of dry matter.

What does fibre actually do for your horse?

It supplies energy. Fibre is fermented in the hindgut into volatile fatty acids (VFAs). That gives steady energy, without the peak you get from sugar and starch.

It protects the stomach. Eating forage takes chewing time, and chewing produces saliva. Saliva and the forage itself help buffer stomach acid. In a Belgian cohort study of 200 horses, a low forage intake was associated with a higher risk of gastric ulcers.

It settles the horse. A horse that spends a long time eating is less likely to stand bored in its stable. Forage is a welfare question as much as a nutritional one.

Who is Maartje Reitsma?

Maartje is a nutritionist at Hartog and studied Animal Sciences at Wageningen University. Her view of feeding horses revolves around fibre – which is exactly why she works for a company that has been drying grass and lucerne for more than seventy years.

What does this series cover?

Every episode connects back to fibre:

• what fibre actually is, and how a horse digests it
• why too much sugar and starch causes problems
• chewing, saliva and stomach health
• the different types of forage
• the dry matter content of your forage
• how much forage your horse is really getting
• what forage does for your horse’s behaviour

Where do you start today?

1. Look at your forage first, and only then at what needs to go alongside it.
2. Weigh, just once, what actually goes into your haynet.
3. Spread the forage across the day so there are no long gaps without feed.

Those three steps cost almost nothing and change more than most supplements do.

Frequently asked questions

How much fibre does a horse need per day? Work with a minimum of 1.5% of bodyweight in dry matter from forage per day. For most horses, 2% is closer to what works in practice.

Is fibre the same as forage? No. Forage is the product – hay, haylage, grass, a forage mix. Fibre refers to the structural carbohydrates within it. Forage is, however, by far the most important source of fibre.

Can a sport horse get enough energy from fibre? Often, yes. Nutritious fibre sources such as lucerne can cover a large part of the energy requirement. Episode 3 goes into this.

Sources

• Merck Veterinary Manual – Nutritional Requirements of Horses and Other Equids: https://www.merckvetmanual.com/management-and-nutrition/nutrition-horses/nutritional-requirements-of-horses-and-other-equids
• Galinelli N. et al. (2021), High intake of sugars and starch, low number of meals and low roughage intake are associated with Equine Gastric Ulcer Syndrome in a Belgian cohort, Journal of Animal Physiology and Animal Nutrition: https://onlinelibrary.wiley.com/doi/10.1111/jpn.13215
• Sykes B.W. et al. (2015), ECEIM Consensus Statement – Equine Gastric Ulcer Syndrome in Adult Horses, Journal of Veterinary Internal Medicine: https://onlinelibrary.wiley.com/doi/10.1111/jvim.13578