Almost entirely preventable, colic is the number one medical cause of death in horses, yet due to misinformation or myth, it remains largely misunderstood. It is important to note that colic itself is not a disease, but the horse’s way of displaying extreme abdominal pain brought on by displacement, impaction, or one of the many other forms of discomfort in the gastrointestinal tract. A proactive approach to stable management, consistency in diet and knowledge of the symptoms is the best way to ensure your horse avoids a colic scare.

An Ounce of Prevention

Equine Guelph declared 2013 the “Year of Colic Prevention” in an attempt to reduce the number of horses that suffer from colic. As part of this initiative, they launched a multifaceted online program that allows horse owners to better understand and implement preventative measures in their stable management programs, identify risk factors, understand the different types of colic and learn how to detect early signs and symptoms. They also presented a free online Colic Risk Rater, to aid in the assessment of colic risk within any stable management program.

The decision to focus on colic prevention was an easy one for Equine Guelph, said their Education and Special Projects manager, Diane Gibbard. “There is often confusion in the horse industry about what colic actually is and, most importantly, what the horse owner can do to prevent it,” she explained. “Many horse owners do not realize how much impact their management routines can have on colic prevention. Even small changes may have a large positive impact.

“As a team, we decided that one of the biggest things we can do to help improve the welfare of horses is to increase the knowledge and awareness of colic prevention through best management practices. We want horse owners to understand that it is not ‘just one of those things’ that horses do, but something that can be prevented with good management.”

Gibbard pinpointed key risk factors that may be lurking in any stable: high grain and low forage diets, unseen levels of dehydration and water intake, sudden changes in diet or routine and limited turnout or increased stall confinement.

Preventative strategies that significantly reduce the risk of colic are easy to implement.

Be consistent in your feeding program and make changes slowly, using a transition period when changing feed. “Horse owners are aware of the importance of transitioning with concentrates,” explained Gibbard, “however, changes in forage – either hay or pasture – is often overlooked, even though this poses the highest colic risk.

“Forage makes up the bulk of the horse’s diet, and the horse relies heavily on its microbial population for fermentation in the hindgut. It takes approximately 21 days for the microbial population to change to a new diet, so be sure to introduce new forage slowly.”

The horse’s digestive system has not evolved to digest large amounts of concentrates. Instead, it’s built to handle a continuous supply of forage. “When feeding concentrates, it is recommended to feed smaller meals of concentrates often throughout the day rather than in one large meal.”

Perhaps most important is to continuously monitor your horse’s water intake and hydration levels, particularly in times of heavy work, where horses sweat profusely or during the cold months when buckets may freeze and horses are less likely to drink. “Water and forage go hand-in-hand; you can’t have one without the other,” stressed Gibbard. “Horses need to consume large volumes of water to keep forage lubricated and travelling through the gut. If the feed is too dry, it will get stuck and cause an impaction. This is of utmost importance when the horse is changing from grass to a hay diet in the fall. A horse’s water requirements will increase as they are eating forage that is lower in water content.”

What to Do

The steps taken when a horse is first suspected to be colicking have major impact on the outcome of what is potentially a life-threatening situation. At times, the signs are obvious. Pawing, rolling, looking at their sides and lack of fecal matter are all symptoms most horse owners associate with colic. Other times, the symptoms are subtle, and it is only the slightest change in attitude or appetite that indicates there may be trouble brewing internally. With so much information (and misinformation), it can be difficult to determine just what to do and when to make the decision to go to the clinic.

Dr. James Carmalt, a professor of Equine Surgery at the Western College of Veterinary Medicine, stressed that the best way to ensure your horse comes out of a colic scare is to follow simple procedures that err on the side of caution. “If you notice that the horse has not eaten his dinner, or is lying down a lot, and if this is different behaviour from the morning, take heart and respiratory rates and the rectal temperature and then call a vet,” he said. “In some cases, monitoring the horse for 30 minutes to determine that the problem is ‘real’ may be acceptable if the horse is calm. Waiting if the horse is agitated is not acceptable.”

In the initial contact with the veterinarian, a few key things can immediately assist in determining the seriousness of the situation. “If possible, I want to know what the heart rate is, when they were last seen to defecate or urinate, the horse’s behaviour and attitude, whether they are pawing, lying down, rolling, calm, distressed or agitated, whether the horse ate or drank recently and when was it last seen to be normal. It’s also crucial to know what, if anything, you have given the horse in terms of medication,” said. Dr. Carmalt.

Your horse’s life may depend on your ability to detect signs of discomfort or pain, and waiting too long due to well-meaning advice from fellow horse people could prove a fatal mistake. No matter how vague, call your vet with your findings. “Waiting too long before seeking help and obtaining incorrect information or diagnoses from non-veterinarians is one of the biggest mistakes I see people make,” said Dr. Carmalt.

“Walking horses may result in them passing some gas, but extensive walking will not prevent a surgical emergency,” he added. “A down horse is okay, a horse that is down and rolling is not. It is far better to load a suspected colic horse onto the trailer to get to the vet than waiting too long and subsequently being unable to load the seriously colicky horse to go anywhere.”

Be prepared for the worst case scenario at all times. Having an emergency colic plan should be considered just as important as a fire plan or other medical emergency.

“Having [access to] a functioning trailer is extremely important,” said Dr. Carmalt. “Tires, trailer lights and brakes need to be checked regularly. Dig the trailer out of the snow regularly during the winter. There is absolutely no point in having a functioning trailer that is useless in an emergency because of a failure of preventative maintenance and forethought. Load horses into trailers with lots of room; take the dividers out, because if the horse goes down in the trailer, getting them out can be extremely difficult.”

Dealing with colic is an extremely emotional time, and making important decisions can be difficult under duress. In addition to pre-planning the logistical aspects of your emergency plan, give some thought to the financial implications colic may present. “Knowing how much the horse is worth to you, how much you are willing to invest and what you are likely to want to do with your horse are extremely important items of information when you visit the veterinarian,” Dr. Carmalt cautioned.

“The medical or surgical management of your horse will be tailored, if necessary, to your financial constraints. That said, client expectation needs to be realistic. If your veterinarian thinks that surgery is the best way to manage the horse, and this is not an option for you, do not be surprised if despite their best efforts, the horse succumbs to the colic.

“Have a financial limit in your head, having discussed it with the family, prior to coming to the vet. Do not make significant financial commitments in the emotional heat of the moment. Most times, this results in a very unhappy client and negative feelings between the client and the veterinarian.”

Surgery and Aftercare

Some colics can be diagnosed with rectal palpation and ultrasound, and resolve medically, while others may require exploratory surgery in order to make a definite diagnosis and correction.

The decision to undergo surgery is not always made as a last resort to save the horse’s life. Often, explained Dr. Judith Koenig, an associate professor at the Ontario Veterinary College specializing in Large Animal Surgery, if the likelihood of a twist occurring is high or the pain is unmanageable, surgery will be recommended. “There are a few parameters we use to decide if a horse needs surgery: if the pain is such that we can’t get the horse comfortable and the heart rate goes up with time; if there are abnormal findings on palpation per rectum that makes us think that something has twisted or the horse can’t correct on its own; if there are findings on the ultrasound that indicate there is a lot of small intestine that is not moving; if we are suspicious of a blockage somewhere; or if we take blood work that is indicating the horse has significant inflammation or endotoxemia. Sometimes, we collect fluid from the abdomen through a belly tap with a small needle, which is called adominocethesis, to see if the fluid in the abdomen has changed colour or has other signs of abdominal inflammation or other abnormalities. As a rule, if wes uspect a twist or another condition that’s not likely to resolve on its own, we prefer to take the horse to surgery before it gets really sick,because the chances for the horse are better.”

Despite the varying types of colics that horses can be diagnosed with, Dr. Koenig said the surgeries are relatively similar in nature. “All colic surgeries follow a systematic approach,” she explained. “You open the horse up on midline, and you try to identify certain landmarks of the intestine that you then lift out of the abdomen; you then use other landmarks to trace the intestine and feel it for abnormalities until you have identified the source. That is sometimes a challenge when the intestine is tied into a Gordian knot [an impossible puzzle], and it’s often very hard to figure out what goes where.

“Once you have identified what is wrong, you can either position it back to normal or, sometimes, you need to empty its contents, which is called an enterotomy, or deflate the bowel to be able to position it back. If the bowel is very compromised, you must decide if you need to remove [a section], which is called a resection, and make a new connection, which is called anastomosis, or if it can be removed. Unfortunately, sometimes the intestine is trapped in spaces where it cannot be removed safely or too much bowel is dead and the horse needs to be euthanized.”

If the location of the obstruction is more difficult to access, it may prolong surgery time and increase the manipulation of the tissues, which has the potential to affect prognosis and recovery time.

The 72 hours following a colic surgery are the most critical, and the months following a colic surgery are an intensive recovery. Horses are usually kept on broad-spectrum antibiotics for at least three days, sometimes longer depending on how the horse recovers, with pain medication given as long as required. Reduced gut motility, referred to as ileus, is a potential complication post-surgery, and it can be fatal.

“Intravenous fluids spiked with calcium are given until the horse can drink on its own to maintain hydration,” explained Dr. Koenig. “Usually, we allow water access within a couple of hours, unless the intestine is not moving. Particularly after small intestinal surgery, which is more prone to ileus, we put the horse on a prokinetic agent, which is a motility stimulating drug. If the horse’s bowel is moving well and no bowel was taken out, food is often reintroduced in small amounts after six to 12 hours.

“We routinely put an abdominal bandage after colic surgery that is changed as needed and is kept for s even days. Hand-walking is usually initiated within 12 hours after surgery and horses are often hand-grazed.”

Though it varies on a case-by-case basis, patients are usually kept on stall rest with hand-walking for one month, small round pen turnout for another month, pasture rest for a third month and then gradually reintroduced to normal exercise.


While horses are often stoic through intense abdominal pain, the general signs of colic are similar across the board. There are, however, numerous variations and root causes. In the majority of colic cases, the specific cause is unknown, which is referred to as idiopathic colic. If recognized and treated immediately, mild cases are often easily resolved, but when left undiagnosed for a period of time, a more severe impaction or torsion can occur. Following are some of the most common types of colic:

Impaction Colic

Impaction colic occurs when an accumulation of ingesta, such as feed or sand, causes an obstruction that prevents proper movement through the digestive tract. “The large colon is a winding mass measuring 12 feet long, carrying up to 76 litres of semiliquid material,” explained Dr. Kathleen MacMillan, assistant professor of Equine Ambulatory Practices at the Atlantic Veterinary College. “Thus, impactions most commonly occur where the colon starts to narrow at one of the three flexures. If diagnosed early, impactions usually resolve without surgery.” Early signs that there may be an impaction include dry manure, decreased appetite and signs of mild to moderate abdominal pain.

Offering free-choice water and careful management of good-quality feed will help minimize the potential risk of impaction colic. Proper hydration and a diet high in fibre will aid in the movement of feed through the digestive tract. Regular dental care can also allow the horse to chew more comfortably and effectively, thus allowing the feed to be mechanically broken down into smaller particle sizes for better digestion. Motility in the large intestine has been directly linked to adequate exercise, and horses on stall rest or limited turnout should be managed carefully to minimize the risk of impactions.

Gas Colic

It is difficult to pinpoint the exact causes of gas colic, but it often comes as a result of inflammation in the gastrointestinal tract due to over-fermentation of food. A horse’s inability to burp or vomit may contribute to the accumulation of excess gas. Characterized by any build-up of gas, the largest risk when dealing with gas colic is the displacement or twisting of the distended bowel. The best way to prevent gas colic is by adhering to a consistent feed program using good quality forage and to make feed changes gradually, allowing the horse time to adjust.

Gastric rupture is a relatively rare result of colic that is most often fatal. Often gastric rupture is the result of a build-up of gas or ingesta after an overconsumption of grain, intestinal obstruction, or parasitic infestation. Clinical signs that a horse may have a gastric rupture include muscle tremors, a drop in body temperature, rapid shallow breathing, and weak pulse. “There really is no treatment for gastric rupture, as the abdomen becomes grossly contaminated with feed material,” said. Dr. MacMillan. “Since horses cannot vomit or burp, the best prevention of gastric rupture is to have the veterinarian examine the horse and decompress the stomach if needed.”

Sand Colic

Environmental conditions and management may contribute to the likelihood of sand colic. The ingestion of sand into the intestinal tract may be a result of routine grazing, eating hay off the ground, mineral deficiency, overstocked paddocks, dental issues or even boredom.

Correct feeding and management practices can minimize the risk of sand colic, but it may be inevitable in certain geographic regions where outdoor horses eat off sandy ground or even ingest the loose roots of pasture. Some sand will make its way through the digestive tract and pass with manure, potentially irritating the intestinal lining along the way. This irritation contributes to the signs of early onset sand colic, which include chronic diarrhea and weight loss. “As the sand begins to accumulate,” explained Dr. MacMillan, “motility decreases and there is an increased risk of impaction in the large colon.”

Because sand is dense, it can be diagnosed using radiographs. In order to determine the amount of sand that is passing through the digestive tract, you can mix a small amount of fecal matter in some water and the sand will separate and rest on the bottom. It is not known what makes certain horses more susceptible to sand colic than others.

Displacement/Torsion Colic

A displacement occurs when the large intestine moves from its normal anatomic location (usually right or left), but does not make a 180-degree rotation or twist. Torsion is one of the more severe forms oF colic, and occurs when the large colon displaces and twists 180 to 360 degrees.

Some displacements can resolve with rolling, said Dr. MacMilllan, who described the procedure as “a non-surgical correction of a lef tsided displacement, resulting in a nephrosplenic entrapment of the large colon between the spleen and the body wall. The horse is placed under general anesthesia, and is rolled in an attempt to free the large colon from the entrapment.”

Many displacements and all torsions, however, require immediate surgery to correct the rotation and repair any section that has been damaged due to a loss of blood flow. “Delayed veterinary examination and surgery may result in a poorer prognosis for recovery,” stressed Dr. MacMillan, “and horses that suffer from a displacement or torsion of the intestines may be considered at a higher risk of colic reoccurrence.”

Spasmodic Colic

Spasmodic colic can be likened to indigestion in humans, and is essentially contractions or spasms of the intestines that prevent anything from moving through the digestive tract. It is often triggered by stress or dehydration, but can also be caused by parasites.


Dr. Kathleen MacMillan of the Atlantic Veterinary College believes that when it comes to colic, there is really only one truth that stands across the board: call the vet. “I think that the average horse owner has some baseline knowledge of colic, but not all have experienced it in their own horse,” she said. “The biggest mistake owners make when suspecting colic is not calling their veterinarian quickly enough. I always tell my clients that if they are unsure or concerned, simply call and we can discuss it. This keeps the lines of communication open and can provide earlier examination of the horse for diagnosis and treatment.”

Another mistake Dr. MacMillan sees being made is the hay and grain not being removed at the onset of the symptoms. “When explaining impactions to my clients, I use the analogy of a 50-car pile-up on the highway,” she said. “Every time the horse eats, it is adding another couple of cars to the accident that the tow truck must haul away. Continuing to feed can make the impaction larger and more difficult to clear.”

While it’s a pretty common adage that a bran mash will improve digestion, it is not necessarily a miracle remedy and shouldn’t be given in all circumstances. “Sloppy bran mashes are great for horses that are already passing manure in a resolving impaction and can be a good way to increase water intake as well,” said Dr. MacMillan, “but they should not be used as a treatment for colic without being examined by a veterinarian to determine the type of colic.”

Dr. MacMillan stressed that even if colic is suspected, owners should call the vet before administering medication. The use of Banamine in the treatment of colic symptoms is common, but it is important to understand that while it may aid in pain management and has the benefit of being an anti-inflammatory, it can also mask the signs of a developing obstruction. With the administration of medication at the onset of a case of colic, you are also risking the false sense of security that you have solved the problem.

“I have dispensed oral Banamine to owners with horses that colic chronically,” said Dr. MacMillan. “What I suggest to them is that they call me first to describe in detail what is going on with the horse and then let me know two hours later if there is no improvement or immediately if the symptoms worsen. Most colics in my practice are mild gas or spasmodic colics that resolve with Banamine administration, whether given intravenously or orally.”

One oft-repeated piece of advice that Dr. MacMillan said is worth taking is: at the onset of colic symptoms, get walking. “I generally recommend to my clients that they walk their horse at the onset of colic because if it is just a mild gas colic, sometimes the walking can help to relax the horse enough that they will begin to pass some gas on their own, decreasing pressure in their intestines and potentially relieving the pain. A rolling horse can increase the risk of a twist due to the colon being distended with gas or ingesta, making it more likely to displace.”

Dr. MacMillan cautioned, “It is important to remember that some horses in severe pain can also be a danger to the owner. If the horse is in so much pain that it cannot be kept on its feet and is thrashing around, then the owner should step away and wait until the veterinarian arrives and can medicate the horse.”

Weather is sometimes blamed for medical issues (hello migraine sufferers!), but can it cause colic? Dr. MacMillan admits that a sudden change in weather can be a factor in the increased likelihood of colic. “I definitely see a cluster of colics when there is a sudden or severe change in weather,” she said. “It also seems that certain horses are more sensitive to these changes. However, it may not be the change in weather itself as much as the change in routine to accommodate the weather.

“If horses are kept in rather than being turned out during a snowstorm, or if the diet was not decreased even though horses had no turnout or exercise, that should be taken into account.”

Dr. MacMillan advocates the use of water and electrolytes to aid in treatment of impactions. “In recent years, horses have been more commonly treated with water and electrolytes via nasogastric intubation, as it more effectively penetrates the impaction and helps it breakdown more quickly,” she said. “Mineral oil is still sometimes used, and is very helpful to evaluate transit time from stomach to rectum, but owners should never attempt to intubate with a nasogastric tube. There is only a 50/50 chance that you are in the correct location, and that should never be attempted by someone who does not possess the skill or the knowledge.”