Understanding colic and suggestions for prevention
It is critical to understand the gastrointestinal tract of the horse in order to understand why your horse is prone to colic. The horse’s digestive tract is broken down into two main sections: the foregut, made up of the stomach and small intestines, and the hindgut that contains the cecum and colon (collectively the large intestines). The horse has a relatively small stomach that can hold only about 2 gallons of volume and horses can only moderately digest the simple carbohydrates (starches and sugars) found in grains. After the stomach, a very long and narrow small intestine further digest foods. It is the site of protein and vitamin absorption. The small intestine empties into the large intestine, which is made up of several sections and is collectively referred to as “the hindgut.” It is within the hindgut, particularly the cecum, that forages (complex carbohydrates like grass, hay, and other fermentable fibers) are fermented or broken down by microbes. There are good and bad microbes populating the hindgut. When conditions in the hindgut are stable and the pH level is well-balanced, the good microbes flourish and the intestinal tissues remain healthy. If the pH level in the hindgut falls too low (becomes more acidic), the less desirable microbes can take over and the intestinal tissue becomes irritated and inflamed. Maintaining proper hindgut pH is very important to a healthy digestive tract. Providing adequate amounts of good quality forage is necessary to maintain an adequate population of beneficial microbes and a healthy hindgut environment.
Consequently, when high volumes of simple carbohydrates (grains) are fed, some of the starch and sugar can escape digestion in the foregut and enter the hindgut. Microbes are capable of rapidly fermenting any and all starch that enters the hindgut. When this occurs, a drastic drop in pH results, making the hindgut more acidic. An imbalance of this sort can lead to diarrhea, colic, and laminitis.
Horses that have experienced several bouts of colic, or have been managed such that they maintain a low hindgut pH (often referred to as subclinical hindgut acidosis due to high grain intake), are more prone to colic. This in part is due to damaged tissue in the lining of the hindgut. When this sensitive tissue is repeatedly or chronically exposed to low pH (acidic conditions) then it becomes a poorly functioning tissue. As a result, the pH can more easily drop (become more acidic), thereby commencing a cascade of ill effects that may lead to serious problems like colic and laminitis.
Maintaining a stable environment for the microbes in your horse’s hindgut is of utmost importance for preventing digestive upsets that lead to colic, diarrhea, and laminitis. This stability can be achieved by minimizing the amount of easily fermented starch and sugar your horse consumes, while maximizing the intake of high-quality fibers. In addition, supplementing with prebiotics and probiotics may level out drastic swings in pH and minimize shifts in microbial populations. Furthermore, proper management techniques—such as feeding frequent small meals, feeding on time, making all feed changes slowly, and always having unlimited clean water available—will contribute to your horse’s well-being.
Important Considerations:
Fat
Fat is an excellent source of energy for horses prone to colic. It is easily digested and won’t cause the rapid fermentation that results in low pH levels (acidic conditions) in the hindgut. Colicky horses still require energy and often require greater amounts of energy than can be achieved from nominal quantities of grain and forage. Therefore, fat from sources such as rice bran can provide energy-dense, safe calories to these sensitive horses. Providing a significant source of energy in the form of fat is an excellent option for colic-prone horses.
Natural vitamin E
Vitamin E is an essential vitamin that horses must consume in their diet to meet their requirements. At rest a horse requires at least 1,000 IU of vitamin E per day. The requirement increases for growing horses, hard-working horses, and reproductively active horses. Ill or injured horses are often treated with high doses of vitamin E. This fat-soluble vitamin plays a key role in the antioxidant recycling system within the horse. A major function of vitamin E is to restore the immune system’s ability to fight free radicals that are produced by normal body functions. Many veterinarians recommend supplementing horses with natural vitamin E to combat the negative effects of exercise, illness, injury, and aging. Horses prone to colic should be supplemented with natural vitamin E to support their immune system and to aid in healing the cecal (hindgut) tissues damaged from chronic acid exposure.
Digestive tract support
Yeasts, fermentation metabolites (prebiotics and probiotics), gastric buffers, and gastric coating agents all help maintain a healthy digestive tract in horses that are under stress or suffering from digestive tract disorders. These ingredients promote a healthy digestive tract by maintaining optimal pH levels throughout the tract, supporting the healing of damaged tissues, sustaining healthy tissues, and nourishing beneficial bacteria. When horses have a healthy digestive tract, they utilize their feed more efficiently, have an increased appetite, and are at less risk of digestive upsets that lead to serious colic episodes.
Omega-3 fatty acids
Horses evolved to exist on a diet that contained both omega-3 and omega-6 fatty acids. Both of these fatty acids are necessary, but the ratio of one to the other is critical. Omega-3 fatty acids are anti-inflammatory in nature and should be found in higher levels in a horse’s diet. Pro- inflammatory omega-6 fatty acids need to be kept at a minimum; this is a healthy ratio for your horse. Modern diets, especially those that include large amounts of grains, tend to be high in omega-6 fatty acids. Supplementing with a high-quality omega-3 fatty acid brings the ratio back into balance. In particular, the omega-3 fatty acids EPA and DHA (found in marine sources of omega fatty acids) are nutrients that aid in decreasing inflammation, which supports the healing of damaged tissues and the maintenance of healthy tissues. Including a broad spectrum omega-3 supplement is recommended for horses suffering from digestive disorders or those eating diets high in concentrates (grains, pelleted feeds, and sweet feed).
Hydration (water intake)
Large amounts of water are needed for the fermentation of fiber to take place in the horse’s hindgut. At rest in a comfortable environment, a horse should drink 10 to 12 gallons of water per day. Water requirements will dramatically increase once a horse starts to sweat in response to warm temperatures, exercise or stress. When there is not enough water in the GI tract, digestion slows and colic can occur.
Regardless of the reason, when horses sweat they lose essential fluids and electrolytes. If enough electrolytes are lost it can lead to a reduction in the horse’s thirst response, causing the horse to stop drinking. Lack of fluid intake results in dehydration and increases the risk of colic and other metabolic failures. Horses that do not drink sufficient water in the winter are at increased risk for developing impaction colic. Therefore, it is critical to supply a balanced electrolyte supplement to replace lost electrolytes when needed, and to stimulate the thirst response so horses remain well hydrated at all times.
