Other symptoms that may indicate a stomach ulcer in the horse are hesitant downhill walking and difficulty lying down.  When the horse goes downhill or lies down, the trunk muscles are used more and the abdominal muscles contract. The contraction of the abdominal muscles increases the pressure on the stomach.

What happens if the pressure on the horse's stomach increases?
When the pressure on the horse's stomach increases, the acidic stomach content sloshes into the glandless front part of the horse's stomach and reaches the sensitive gastric mucosa. If the gastric mucosa is already affected by ulcers, this leads to further irritation of the mucosa, which in turn causes additional pain in the horse.

Why do horses have more frequent stomach ulcers in the front part of the stomach?
In principle, the horse's stomach is divided into two parts. The mucous membrane of the anterior part of the stomach does not consist of glandular tissue. Here a low microbial conversion of the easily digestible carbohydrates and partly also of protein takes place. During the conversion of easily digestible carbohydrates, lactic acid and, in small quantities, acetic and butyric acid are formed, which acidifies the feed mash. In the posterior part of the stomach, glands are embedded in the mucous membrane, which form the gastric acid, consisting of pepsin and hydrochloric acid. While the feed passes the horse's stomach, the pH value is lowered from about 5.5 to below 3 (depending on the amount of concentrated feed, among other things).

To prevent the stomach from digesting itself in the back, the inner stomach wall is protected with a thicker layer of mucus. If more gastric acid is produced due to stress, an excess of gastric acid occurs, which cannot be sufficiently buffered if roughage intake is insufficient and salivation is therefore low and consequently attacks the glandless mucous membrane in the anterior part of the stomach. Excessive amounts of concentrated feed also lead to increased formation of lactic acid in the front part of the stomach, which additionally lowers the stomach pH and thus damages the stomach mucosa.

In addition, too little saliva is produced by too much forage and too little roughage due to the associated lower chewing activity. This means that there is not enough bicarbonate (part of the saliva) to buffer the acid. In addition, too little saliva prevents the feed mash from becoming a homogenous mass. This slows down the passage time of the feed, so that the feed mash stays longer in the stomach and becomes more acidic due to the constant production of gastric acid.

It is therefore important to feed enough roughage throughout the day.  Provide the concentrated feed according to the needs of the horse but give it after roughage administration so that the horse has already formed enough saliva to buffer the acid in the stomach.