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The Horse's Digestive System

By Karl-Wilhelm Hermanns

Over a period of many millennia, horses have had to adapt to their environment and natural habitat. As a result of this adaptation, they became herbivores and in order to cope with this they developed a highly specialized kind of digestive system which is not seen in any other animal species.

The horses are normally occupied with their food intake for almost 20 hours. Their diet consists mainly of grass, herbs, shrubs, and leaves. Once in a while they treat themselves to seeds, granules or fruit. As a result, their nutrition is very rich in fiber, but poor in carbohydrates. During certain times of the year their intake of proteins and vegetable fats is rather low. Due to the low energy content in their natural feeds, the horses have no option but to spread large amounts over a period of 24 hours. These fiber-rich feeds have to be chewed very thoroughly. For this purpose, the horses produce a copious flow of saliva manufactured as a result of the intensive chewing process, which ensures that the feed is well broken down before it reaches the stomach. This process is an essential prerequisite for the horse's digestion.

Since the food intake is so slow and protracted, the stomach receives only small portions at a time. The initial breakdown of the nutrients by the enzymes and bacteria, which are contained in the feed, takes place in the anterior part of the stomach (known in medical terms as the aglandular cecal pouch). The second half of the stomach (the medical terms of which are fundus and pylorus) handles the supply and saturation of the contents with the horse's own gastric acids. During this process the pH-value drops down to below 2.5. In the course of this, the microorganisms contained within the feed are eliminated, the pepsin (which is a protein-splitting enzyme) is activated and this initiates the breakdown of the proteins into short chains (di- and tri- peptides). After about 4 hours, the stomach contents finally reach the small intestine. In the small intestine the pancreatic secretions and the bile are carried into the small intestinal system. The pancreatic secretions contain all the enzymes, which are necessary for the splitting of the principal nutrients, namely proteases for protein splitting, amylases for the amylolysis, and lipases for the release of lipids. In the course of this process, the alkalis required for the increase of the pH-value (up to pH 7) are multiplied and it is only within the neutral pH-range that all the enzymes become activated 100 %. This is the only way in which the amino acids produced by the protein, as well as the sugar molecules produced by the carbohydrates and the fatty acids produced by the fat can be utilized by the small intestine and its mucosa.

What is different in horses by comparison with other animal species is the fact that the pancreatic secretions contain a low concentration of enzymes.

"Horses do not have any Gallbladders".

The digestion of fats is assisted by the liver, which provides a continuous supply of salt-containing bile. The existence of a mineral stone is of the utmost importance.

In order for the nutrients (proteins, fats and carbohydrates) to be able to pass through the 60' long small intestine, they have to be fully absorbed and digested, otherwise they will be lost for ever.

Within the small intestine an entirely different strategy governs the digestive process. Here you have a plentiful supply of bacteria and these are capable of splitting the fibrins which the horse would find hard to digest, resulting in short-chain fatty acids (acetic acid, propionic acid, butyric acid). These acids are very energy-rich and are therefore indispensable suppliers of energy for horses. The bacteria produce valuable vitamins (B-vitamins, vitamin C and Biotin) which the horse may not necessarily get from, its feeds. However, in cases where there are disorders of the digestive tract, the above-named may be either in short supply or may not be produced at all.

A number of different bacteria turn the large intestine into a virtual fermentation chamber and this also includes the appendix and colon. But not all the bacteria are necessarily good ones. Just like with any other fermentation process, there may be unwanted side effects, which can easily lead to the development of colics. When undesirable bacteria of this type multiply, the horse cannot always cope and they may turn poisonous or even fatal. They can also cause long-term damage to the horses' health (hoof-laminitis, liver-damage, colics etc.). The food may remain in the large intestine for up to 48 hours and after that it is normally excreted in well-formed bowel movements, when the horse is in good health.

In the modern horse-world an amazing number of mistakes occur on an on-going basis. This is not just the fault of the horse owners themselves but even more due to the greed for additional profits exhibited by the industry, as a result of which the protein content in the horse feeds is often far too high and contains far too many animal by-products. The hay is far too rich and as a result the horses are often very short of raw fiber. The feeds do not contain a sufficient amount of minerals and vitamins, but worst of all these have been added in an inorganic or synthetic manner, which means that the horses are unable to derive any benefit from them, making them totally useless and a complete waste of money.

However, nowadays there are many ways and means of avoiding all these problems and getting things back to normal by natural means. All you need is the right kind of information and a slight change in attitude.

Here is just one example:

Nowadays many of the herbs, which are missing from our hay and pastures, need to be replenished. Sunflower seeds, linseed and plant germs, for instance, supply fats, minerals and vitamins in a natural composition, which is well absorbed and utilized by the horses.


If you have any questions regarding modern equine nutrition or the elimination of problems connected with your horses, please contact either the author himself or Mrs. Regina Hermanns, who will be pleased to show you how to get your horses back into excellent shape and health.

The above is based on the author's personal opinions and his 35 years experience in horse breeding. To get more information from Karl Hermanns and Topfit of America contact him at k.hermanns@topfit-online.com or call 888-373-3853.


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