How a horse’s digestive system works

healthy wearing of the teeth and leads to increased saliva production.
Did you know that adult horses may secrete up to 3540 litres of saliva per day? Saliva plays a very important role in lubricating the food ingested and buffering stomach acid which is important for the prevention and management of gastric ulcers.
Digestive system inside a horses stomach
Once food has been swallowed it passes down the horses oesophagus into their stomach. A horses stomach contains gastric juices pepsin and hydrochloric acid which break down food into semidigested liquid chime. The stomach is made up of two types of tissue and the lower section is lined with glandular mucosa which secretes acid to help digestion.
A horses stomach can be divided into the following two parts separated by a line called the margo plicatus
The lower part of the stomach has a glandular lining and it is here that the acid is produced in response to a complex pathway of stimulatory and inhibitory signals.
The upper part of the stomach has a squamous lining. It is this part of the stomach that is sensitive to contact with the acid from the lower part which can in some cases lead to gastric ulceration.
The lower area also produces mucus and has protective mechanisms to ensure its not damaged. The upper section is lined with squamous mucosa which doesnt have this protection so is therefore vulnerable if it comes into contact with stomach acid explains Sara.
The stomach empties when two thirds full which means continuous foraging or several small feeds are preferable to large ones. A horses stomach is a muscular organ thats about the size of a rugby ball between nine and 15 litres which is very small.
This is because horses are designed to trickle feed eating little and often and the majority of digestion occurs in the hindgut explains Sara.
Digestive system inside the small intestine
Once processed by the stomach semidigested food passes through a valve the pyloric sphincter into the small intestine. This is around 25 metres long in a 500kg adult horse
The jejunum and caecum
The jejunum is roughly 19m long and the chemical breakdown of food is finished in this part of the small intestine with nutrients absorbed into the bloodstream to be used by the body or stored in the liver.
The ileum around 1m long is the final part of the small intestine. It continues the absorption of nutrients and controls the passage of partially