EQUINE COLIC: CAUSES, SYMPTOMS, TREATMENT AND PREVENTION
Adapted from the Online Equine Nutrition Course,
My Horse University
Colic: Causes and Symptoms
Colic is defined as any abdominal pain although horse owners typically refer to colic as problems with the gastro-intestinal tract. The causes of colic are numerous, but generally they are related to the anatomy and the microflora of the horse's gastrointestinal tract. Some more common causes of colic include:
Impaction: a blockage formed by something the horse has ingested
NSAID: non-steroidal anti-inflammatory drug
Figure 1. Parasites, such as strongyles can be a common cause of colic. It is important to practice a deworming routine to prevent parasites in equine. (Image right)
Antibiotics may lead to colic because they alter the microbial population in the gut, which in turn affects starch digestion. Dental problems may cause colic if the horse is unable to chew its food sufficiently. Older horses fed coarse hay are at greater risk of impaction colic.
Signs of colic include:
Figure 2. Photo of horse rolling due to colic.
A colicky foal may not show typical signs of colic. Instead, they may lay on their back with their legs tucked. The foal owner or manager needs to be on alert for any abnormal foal behavior.
Figure 3. This foal has a distended abdomen due to gas.
Source: Dr. Judy Marteniuk, Michigan State University
Types of Colic
Colic is related to many different maladies and include the following:
Stomach distention – the small capacity of the horse’s stomach makes it susceptible to distension when large amounts of grain are ingested in a single meal. There is the potential for the stomach to rupture which is fatal.
Displacement colic – the small intestine is suspended by in the abdominal cavity by the mesentery and is free floating in the gut. This mobility can predispose the small intestine to become twisted. A twisted intestine requires immediate surgery to reposition the intestine and remove any portion of the intestine that is damaged due to restricted blood flow. In addition, both the small and large intestine can become displaced in the abdominal cavity causing both pain and restricted blood flow. Displacement colic can be caused by gas build up in the gut that makes the intestines buoyant and subject to movement within the gut. Displacement colic needs immediate surgical treatment.
Figure 4. Small intestine. The small intestine is attached by the mesentery, a thin membrane that allows the small intestine mobility in the abdominal cavity.
Impaction colic – the large intestine folds upon itself and has several changes of direction (flexures) and diameter changes. These flexures and diameter shifts can be sights for impactions, where a firm mass of feed or foreign material blocks the intestine (including the cecum). Impactions can be induced by coarse feed stuff, dehydration or accumulation of foreign material like sand.
Figure 5. Large intestine. Impaction colics are commonly located in the cecum and large intestine.
Gas colic – all colics are associated with some gas build up. Gas can accumulate in the stomach as well as the intestines. As gas builds up, the gut distends, causing abdominal pain. Excessive gas can be produced by bacteria in the gut after ingestion of large amounts of grain or moldy feeds. A nasogastric (stomach) tube inserted by a veterinarian is used to relieve the pressure of the gas and fluid accumulation in the stomach.
Spasmodic colic - defined as painful contractions of the smooth muscle in the intestines. Spasmodic colic has been compared to indigestion in people and is usually easily treated by a veterinarian. Over excitement can trigger spasmodic colic.
Enteritis – inflammation of the intestine possibly due to bacteria, grain overload or tainted feed. Horses with enteritis may also have diarrhea. Enteritis is often hard to diagnose and may present itself similar to displacement or impaction colics.
To give the proper treatment for colic, it is important to determine the cause, so that it can be corrected. The severity of the signs of colic is not necessarily indicative of the severity of the colic, and sometimes it is difficult to determine the exact cause and therefore the correct treatment. For these reasons make sure to have a veterinarian evaluate your horse as soon as possible. Many cases of colic can be treated successfully with medication, while others involving severe impactions or twists may require immediate surgery.
While you are waiting for your veterinarian, you should:
Observe your horse and monitor vital signs as well as passing of any feces. Remove access to feed. If there is a blockage, any feed intake will only intensify the problem.
Let the horse rest as much as possible. It is not necessary to walk the horse unless the horse is rolling and endangering himself or people.
Do not administer any medication without the direction of the attending veterinarian. Pain medication may mask the colic symptoms and complicate diagnosis and treatment. In addition, banamine if administered in the muscle can cause a clostridial abscess that can be fatal. Banamine should always be administered intravenously or orally.
Upon arrival, the veterinarian will listen for gut sounds, monitor vital signs, pass a nasogastric tube and perform a rectal exam. Most colic cases can be treated on the farm with medication and the use of a nasogastric (stomach) tube to alleviate gas and administer medications. However, if the veterinarian suspects a displacement or an impaction that can't be successfully treated on site, she will refer you to an equine surgical hospital.
Once you figure out the cause and have treated the colic, some of the preventative measures are self-explanatory. For example, if an abrupt change in diet caused a problem, make sure to make dietary changes gradually in the future. Some other preventative measures include:
Feed your horse on a regular schedule even on the weekends.
Do not make sudden changes to the horse's diet.
A clean fresh water supply should always be available.
Keep feed boxes and hay racks as well as the feedstuffs clean and free of mold and dust.
Check teeth frequently for dental problems that may cause chewing issues.
Provide adequate exercise.
Feed the appropriate amount of forage (at least 50% of the total diet).
Keep feed off the ground to avoid sand ingestion.
Practice an effective parasite control program that fits your farms needs.
Figure 6. This horse is consuming hay on sandy ground which could lead to ingesting sand and potentially sand colic. Sand colic is more common in sandy parts of the U.S. (Image left)
References and Additional Resources
eXtension HorseQuest Article: Management and Control of Internal Parasits in Horses
eXtension HorseQuest Article: The Role of Nutrition in Horse Colic and Laminitis