- a significant impact on overall equine health
The horse’s large intestine breaks down fiber—the type of feed horses consume the most. Feeding and management practices have a major influence on the health of this crucial part of the digestive system.
Digestive problems are common in horses and can present in many ways, such as abnormal behavior, weight loss, or colic. Horses are monogastric like humans, but unlike humans, they are hindgut fermenters.
The horse’s digestive tract is divided into two parts:
- Foregut, which includes the stomach and small intestine, where enzymatic digestion takes place.
- Hindgut (large intestine), consisting of the cecum and colon, where fermentation occurs.
The role of the large intestine in equine digestion
Horses digest starch and other soluble carbohydrates in the small intestine. Because horses lack fiber-digesting enzymes in the foregut, fiber passes undigested into the large intestine. Since fiber makes up the majority of the horse’s diet, fermentation is vital for digestion.
During fermentation, microbes in the hindgut use fiber as an energy source. As a by-product of fermentation, volatile fatty acids are produced, which the horse then uses for energy. This is a symbiotic relationship—the horse and its gut microbes both benefit.
Each section of the large intestine has its own microbial population with different functions. Most fiber fermentation occurs in the cecum and colon, while water absorption mainly takes place in the rectum.
Common large intestine problems in horses
Many equine health issues are linked to imbalances in gut bacteria. Sudden changes in feeding, for example, can shock the microbial environment and lead to digestive disturbances.
One example of poor management is feeding a large portion of bran or mash once a week (for example, on Sundays) when it is not included in the diet on other days. This sudden change can disrupt microbes and cause intestinal problems. The same applies to abruptly switching from one type of hay to another.
Disorders of the large intestine may present as weight loss, a dull coat, irritability or aggression, or digestive problems such as colic or diarrhea.
Intestinal diseases such as colic and colitis (inflammation of the colon or rectum) are among the leading causes of death in horses. These conditions can affect the gut microbiota—and conversely, an imbalanced microbiota can predispose horses to them.
Large intestine problems can also be worsened by antibiotic use, lack of exercise, and periods of fasting. Antibiotics may kill beneficial bacteria and allow harmful microbes to proliferate. Some bacteria produce excessive gas, leading to colic, or acids that lower gut pH and kill beneficial microbes.
How to reduce the risk of large intestine problems
The horse’s digestive system evolved for continuous grazing and movement. In domestic conditions, a horse’s lifestyle differs greatly from this, which is linked to hindgut problems. Horses should be allowed to move freely as much as possible and eat small amounts of forage continuously or as frequently as possible. All feeding and management changes—whether introducing new feeds, pasture, or other changes—should be made slowly and in a controlled manner.
Additional points to consider:
- Travel, exercise, and illness can affect gut balance.
- Keep daily routines as consistent and regular as possible. Bring your own hay when traveling or competing.
- Antibiotics should be used judiciously.
Summary
The equine digestive system evolved for a high-fiber diet with minimal fasting. Consistent feeding, gut-friendly management, and minimizing stress help prevent hindgut problems such as colic, colitis, weight loss, and behavioral changes.
Source: The Horse Magazine
