The Digestion of the Horse

The digestion of the horse

The physiological digestion of the horse proceeds in two phases und is simplified in the following.

In the first phase the chewed feed runs through the gullet into the stomach and onto the small intestine. Once it arrives there, digestive liquids from the intestine, the pancreas and the liver cause the break down of carbohydrates, proteins and fats. This is where the intake of vitamins, minerals and trace elements takes place. So the ingredients of concentrate feed and nutritionals are mainly digested in the small intestine.
In the second phase the feed enters the colon, in which a microbial digestion takes place that differs from the enzymatic digestion. The colon processes everything that couldn’t be digested before, like for instance crude fibre. Due to its gut flora, which consists of useful bacteria and protozoa, the colon works similarly to a biogas plant – it generates energy. The feed mass remains here for around 40 hours while a slow bacterial process filters out highly digestable fatty acids and crude fibre, in order to supply the horses body with energy.

The main dangers to the colon are a lack of chewable crude fibre, as well as “too much” easily digestable carbohydrates. Great amounts of concentrate feed were obviously unknown for the wild horse and the digestive system of our modern horse has still not adapted to that.

So who feeds too little crude fibre, starves the microorganisms of the colon.

That way, if you feed your horse large portions of concentrate feed at once, you run the risk of poisoning bacteria with starch and sugar that make their way into the colon which subsequently leads to the production of lactic acid. This can have fatal consequences for the rest of the horse’s organism. To maintain the horse’s health, an intact gut flora is extremely important!
It is proven for all living beings that 60-80% of the immune proficiency is covered by the gut flora. Consequentially, a healthy nutrition is the best way to maintain the horse’s health! If, for instance, the gut flora is disturbed by treatment with antibiotics or a bad diet, this issue can reveal itself in various ways. Colics, eczemas and even laminitis can be ways in which the colon draws attention to its imbalance. In this case, intestinal repair or a change of diet is necessary.

The stomach

The horse is naturally a constant eater and permanently produces gastric acids – however it only produces saliva when it is chewing.

What does that mean for your daily feeding?

Horses should have constant access to high quality hay (very little dust, no mold)!
A horse’s stomach is made to permanently digest small portions of feed. If it is unable to do that because it is empty, the undiluted gastric acids start to attack the inside walls of the stomach. Long phases of chewing and the subsequent production of saliva neutralizes the gastric acids and can prevent gastric ulcers. This should also be considered before training. It is true that the intake of concentrate feed before exercising can have harmful effects, however a constant access to roughage can lower the pH-value in the stomach and prevent a “swapping” of the gastric acids.
Thanks to its 40m-long intestine, the horse can extract all the important nutrients from various kinds of herbal and vegetable structures like semen, fruits or grass. However, in the course of evolution, efficiency remained relatively disregarded. Accordingly, horses have to eat plenty of crude fiber, in order to extract a sufficient amount of nutrients to meet their requirements.
That is why it is crucial only to give concentrate feed in small portions divided in several meals per day and to add hay to each of these portions.