Digestive System of a Horse and Prevention of Upsets

Reproduced with permission of Otter Co-op Feeds


The digestive system of a mature horse is over 100ft long and is make up of 5 key sections:

  • Stomach
  • Small intestine (70ft)
  • Cecum (4ft)
  • Large Colon (10 – 12ft)
  • Small Colon (10 – 12ft)


Horses are excellent fibre digesters.  They have a very large hind gut for digestion of fibre, and fibre is required for horses to maintain optimum digestive system health.  Horses require a minimum of 1% of their body weight in forage with 1.5% to 2% being normal for a mature horse.


When a horse is fed forage and grain it takes about 2 hours to reach the cecum and yet takes as long as 70 hours to pass through the rest of the digestive system.  If too much concentrated feed is fed at one time it can overpower the small intestine and will pass right through to the large intestine where it will ferment and produce gas and harmful by-products that can cause colic or laminitis.


To help prevent digestive system upsets that may cause colic follow these few simple rules:

  • Feed grain to horses in two or more feedings, increase feedings when higher grain levels are used. Never feed more than 2.2kg of grain at any one feeding;
  • Avoid sudden feed changes. Studies show that two or more changes in hay or one or more changes in grain per year will increase the chance that horses will colic.  Allow 2 weeks for a gradual change to any new hay or grain added to diet;
  • Keep a regular feeding schedule;
  • Avoid coarse/poor quality hay that may cause impactions or that contain molds. Usually a good quality grass hay or grass and legume mix will work well for horses;
  • Avoid decreases in water intake by making sure drinkable water is available at all times to help prevent colic; and
  • Regular exercise will help a horse’s general health.


Remember, colic can be prevented.