Our horses' digestive systems are designed for feed that is rich in structure, high in protein and relatively low in energy. This is due to the fact that the horse is actually a steppe animal whose digestive system still functions today as it did thousands of years ago. Therefore, if they could, horses would spend 12-18 hours a day eating. Short rest periods for digestion follow after or between feeding times. Unlike humans, horses are able to digest crude fiber particularly well and use it as a source of energy.

What is crude fiber?

Crude fiber includes cellulose, hemicellulose, pectin and lignin. Roughage is particularly rich in crude fiber. These include hay, straw and haylage, whereby the dry matter content of roughage should be over 50%. Silage or haylage with a lower dry matter content should therefore not be regarded as roughage. The purpose of roughage is to cover the horse's energy requirements on the one hand and its structural needs on the other. The digestion of roughage or crude fiber takes place primarily in the large intestine, more precisely in the cecum. As the horse cannot produce enzymes for this, it relies on bacteria to digest crude fiber.

In contrast to humans or other monogastric animals (creatures that only have one stomach), horses can break down crude fiber through microbial digestion and make good use of it for energy. The crude fiber content of a total ration should be between 18 and 25 %.

Roughage promotes the horse's salivation

The structure or crude fiber in the roughage stimulates chewing activity and thus stimulates saliva production. The coarser and more structured the feed is, the more the horse chews, the longer the eating times are and the more saliva is produced in relation to the amount of feed. If you compare the eating behavior when consuming concentrated feed with that when consuming roughage, you can quickly see that the horse needs considerably more time to eat 1 kg of hay than when it eats 1 kg of concentrated feed.

Consequently, saliva production is higher when eating roughage. Saliva is necessary to buffer the pH value in the stomach and keep it at a natural level. If the horse does not consume sufficient amounts of roughage to meet its needs or if the roughage has too little crude fiber content, the horse eats too quickly and does not produce enough saliva.

Too little crude fiber leads to problems with the horse's digestive tract

The result is a drop in the pH value in the stomach and intestines and consequently mucosal irritation and mucosal lesions as well as stomach or intestinal ulcers. To prevent this, the horse should therefore be given enough roughage (at least 1.5-2 kg per 100 body mass) with sufficient structurally effective crude fiber. Straw alone is less suitable here, however, as it has a high lignin content and therefore does not provide the horse with enough nutrients.

Although lignin is part of the crude fiber fraction and promotes chewing activity, it is not a structural carbohydrate. This means that lignin cannot be used by the horse for energy. The most suitable roughage for horses is high-quality hay (first cut, cut time: after flowering and before sowing) with a crude fiber content of approximately between 25 and 35%.

The digestibility should be between 50 and 60 % and the moisture content should be below 15 % to avoid mold. The quality of hay can be determined by laboratory analysis of the feed, but good hay can also be recognized by its green color, good smell and freedom from dust and mould.

More on this topic

You can find lots more information on feeding horses with stomach problems on our topic page Feeding horses with stomach problems.

Horses with stomach problems need additional support. It is important to know which feed is suitable for your horse and which should be avoided .