The digestion

The horse's digestive system and physiological needs have not changed for at least six thousand years. Their food, unfortunately, yes.
In the wild, the horse eats small amounts at a time, but very often the horse spends an average of 16 hours a day searching for its food. Being a herbivore, it can only eat plant food. This has a very high cellulose content which requires a very long fermentation.
The digestive tract of a horse is perfectly adapted to this fermentation: the cecum and the large intestine are relatively well developed and filled with micro-organisms which degrade cellulose into volatile fatty acids. In addition, this fermentation releases so much heat that the horse does not need to draw on its reserves.

It is during chewing that the horse produces saliva. This saliva is necessary to neutralize gastric acidity. Also it is important that he chews a lot. To compare:
* 1 kg of granules gives 1 liter of saliva and requires 600 chews
* 1 kg of fodder gives 3.5 liters of saliva and requires 2200 -2500 chews.

The fermentation process takes place mainly in the cecum and large intestine. The stomach capacity is relatively small: 10-15 liters, so never give more than 3 kilos of industrial food at one time. The stomach is just the “waiting room” where food is prepared and cleared of bacteria, only after which it will be properly processed in the small intestine.
In the intestines, enzymes and bacteria are involved in proper digestion and absorption of food substances. The balance of intestinal flora is very important. An imbalance in this can lead to unfortunate consequences resulting in a reduction in the absorption of nutrients. Much of a horse's physical ailments and illnesses are caused by the intestines.

Some data
*Stomach: 8-15 liters; 7 - 9% of the digestive tract; absorption: nothing; beginning of digestion by: some enzymes.
*Small intestine: 15-24 meters; 20% of the digestive tract; absorption: fats, starch, sugars, proteins, vitamins A, D, and E; by: enzymes.
*The cecum (1 meter, holds up to 33 liters) and the large intestine (5-7 meters, holds up to 66 liters); overall: 66% of the digestive tract; absorption: water, minerals, especially phosphorus, vitamin B, the remains that the small intestine could not digest; by: bacterial fermentation.

Digestion problems
Some horses constantly have digestive problems; for example: gluttons, straw eaters, manure eaters, thin horses, horses susceptible to laminitis, colic, those with stiff muscles, engorged limbs etc., horses that can hardly relax , horses with capricious appetites etc.
It is possible that all of these problems are caused by unbalanced digestion. I repeat: the horse is by its nature accustomed to absorbing small quantities and these quantities are spread over 24 hours. Very often we give excessively large rations of fodder with high energy value twice a day. The horse cannot digest such large quantities at once. Certain food substances then arrive unprepared in the large intestine. This is particularly evident in the event of a massive intake of starch: transit through the small intestine will take place without all of the starch having undergone the digestive process; it will be found as is in the large intestine where it will be transformed into lactic acid, resulting in a harmful acidification of the environment and a negative effect on the “good” digestive bacteria.
Harmful bacteria can grow, competing with beneficial bacteria, and toxins are synthesized, which can pass into the bloodstream.
Under these conditions, the risks of colic and laminitis are increased, and part of the energy intake cannot be used. It is always advisable to give the horse its daily food in three or four portions, spread over the day. Digestive problems are also often linked to living conditions and extrinsic causes: change in atmospheric pressure (for example the arrival of a storm), moving, poorly conducted or irregular training, all kinds of stress, anxiety, a friend who leaves...

Don't forget that the horse is a very sensitive being, its entire soul is found in the intestine. Try to give it the most natural life possible!