Horse Colic– What Are the Causes?
Colic is the term used for abdominal distress that horses commonly encounter. The incidence of colic in horses is quite high. It is estimated that 10-11% of the horse population undergoes a bout of colic every year.
By Jay Altman, DVM and Assure™ and Assure Plus™ Assurance Program
This is a startling number when one considers that colic is still the condition that accounts for the most deaths in horses each year. For equine veterinarians colic is, by far, the most common cause for emergency calls and distressed horse owners. Although there have been great strides in equine medicine and surgery over the past 25 years, and the ability to treat and cure many colic conditions has drastically improved, there is no single answer or drug that will end all colic.
What causes colic, or even what are the various causes of colic, can be a confusing topic for the horse owner. When discussing the causes of colic it is helpful to try and separate the anatomical and physiological conditions that may be involved in the colic and the trigger mechanisms that may have prompted the condition. For instance, a large colon impaction may be the anatomical and physical cause of the pain associated with your horse’s colic, but lack of fresh water and resulting dehydration may have been the cause of the colic.
The equine abdomen contains approximately 100 feet of small and large intestine. Problems relating to colic may occur at any point in this vast digestive system, including the stomach, the small intestine, the cecum, the large intestine, the small intestine and the rectum. Naturally, many horse-owners consider the stomach when talking about colic, and the recent popularization of information regarding gastric ulcers has helped to reinforce this thought process. But, the stomach plays a minor role as a site of colic pathology. In fact, some retrospective studies have shown that only 3-4% of colic cases are due to pathology, such as ulcers, in the stomach. The vast majority, 64-68%, of colic disease states are related to the hindgut, including the large colon, small colon, cecum, and rectum.
Additionally, a study of 180 performance horses published in March of 2005 showed that 97% of the horses had ulcers of either the stomach, the colon, or both, and 63% of this population had colonic ulceration. Some of the pathological causes of colic include gas accumulation and distention, feed impaction, sand impaction, vascular compromise, motility disturbances, colitis (inflammation of the colon), adhesions of tissues, displacement of a section of colon, and torsion or volvulus of a section of colon.
What causes these pathological conditions?
This question, posed by many clients, is one that equine veterinarians are confronted with on a daily basis. Although in many cases it is impossible for you or your veterinarian to know the exact cause of the colic, in other cases an inciting cause can at least be suspected. Since a large percentage of colics are related to management, there is an advantage to knowing, or at least having a hypothesis as to what caused the colic. Theoretically , there is some item or items in the horse’s management that can be identified, to help reduce the risk and or incidence of future episodes of the same type of illness.
Discussing all of the causes and management mistakes that can lead to a colic situation is almost impossible. Instead it is valuable to review the management practices that can positively influence and reduce the risk of colic. The following list of management strategies should help the horse owner to review his or her current management and determine if they are doing their utmost to reducing colic risks.
1 Implement an effective internal parasite reduction program
Pay close attention to your horse, so that disease and or illness can be detected and attended to in a timely fashion.
Each of these strategies is a complex and detailed topic. Furthermore, for most horse owners several of the most important strategies can be difficult to maintain. It should also be apparent that many of these guidelines relate to the horse’s diet and therefore, gastrointestinal health. The second major category of management involves stress. Stress for horses can come from many different types of management situations and changes. Environment and housing, trailering, changes in surroundings, changes in horse population, changes in feeding schedules, and changes in exercise schedule can all be considered stressors. Horses and horse breeds vary in their ability to handle stress and, just as in people, what constitutes a stress to one horse may not be a stressor to another horse.
Maintaining your horse’s natural diet requires feedstuffs that consists predominantly of roughage or high fiber plant material. It is difficult for many horses to maintain adequate weight on a diet consisting of only roughage, since the energy expended, when in work, is higher than the calories provided by this type of diet. Adding a higher calorie concentrated ration to the horse’s roughage requirement becomes essential to maintaining weight and energy. The problem with this feeding regimen is that the concentrated rations provide a high level of non-structural carbohydrates, which alter the gastric and colonic ph and environment. These changes to the gastrointestinal physiology lead to an environment that for many horses predisposes them to gastric and colonic irritation and ulcers and therefore many types of colic and in some cases significant issues with diarrhea.
A combination of high grain diet, nervous personality and management stresses can place some horses in the high-risk category when evaluating the chances of colic. There have been some efforts over the past few years on the part of both the veterinary community and the feed industry to try to alleviate these conditions. By altering the concentrated feeds that are used to maintain horses, and developing add on products that will help to counteract the negative effects of high grain diets and stress, the industry is attempting to better address the gastrointestinal requirements of the horse. It is important that horse owners analyze their horses management routine and diet to help reduce the individual’s risk of colic.
Jay Altman, DVM Equine Research Associates, Ltd. Read about Sand Colic by the same Author.
