By Timothy G. Eastman, DVM, DACVS, MPVM
Published in Bay Area Equestrian Network December 2006
The word “colic” comes from the Greeks and means “abdominal pain”. Horses are notorious for colic and are predisposed to it when compared to other species. Signs of colic include but are not limited to: being “off feed,” depressed, looking/biting at the flanks, stretching as if to urinate, kicking at the abdomen, and rolling in pain. Most long-time horse owners have experienced at least a mild case of colic in their barns. Generally, a couple of injections and some laxatives will take care of most cases. If not, a repeat visit is required for further more aggressive treatment.
There are many factors that predispose horses to colic. Equine species have simple stomachs unlike most other grazing animals and are unable to vomit. They evolved grazing over most of their day but are now fed several large meals at once, morning and night. Horses also experience much more stress than their mustang counterparts with their busy show and travel schedules. Most often horses with colic have an over accumulation of gas in their intestines (“gas colic”) or a mild impaction. The cause is oftentimes undetermined but can be triggered by a change in feed, dental abnormalities, environmental stress (“change in the weather”), or transportation to name a few. Certain regions have forms of colic unique to their area, for example enteroliths/intestinal stones in California, or “ileal” impactions in the South (the ileum is the last segment of the small intestine and prone to impactions in areas that feed coastal Bermuda grass hays).
In over 95% of the cases of colic that equine veterinarians treat in the field, horses respond to medical management. Flunaximine (Banamine®) is often given because it controls pain, reduces fevers, decreases inflammation, and binds toxins sometimes released by bacteria. Dipyrone is a drug given to reduce spasms of the GI tract and to reduce fevers. Buscopan ® is a new drug to the USA but has been used over seas for many years and has become very popular for treating colic. It is a potent, short-acting drug that reduces spasms of the intestinal tract. It also facilitates rectal examination because it relaxes horse’s rectums. Horses with colic are frequently sedated because the tranquilizers we use are among the most potent pain killers available and begin to work very rapidly. Tranquilization also makes passing a stomach tube and performing a rectal exam easier, safer, and less stressful for the patient.
Stomach tubes are passed up the nostril, down the esophagus and into the stomach to relieve gas pressure from the stomach, and to empty the stomach of feed and water that are not passing through in a normal time frame. A “twitch” is oftentimes placed in order to making the tubing process less stressful and reduce the chances of a bloody nose. While sometimes dramatic to witness the event, passing a stomach tube may be considered an important part of the management of a particular case of colic. Once the tube is passed and gas relieved, medication may be pumped down the tube. Mineral oil is very popular to use as a laxative. Other veterinarians prefer a detergent (“DSS”) to soften horses up and help eliminate gas. Epsom salts are sometimes given to soften up impactions. What drugs are given and by what route are the preference of the treating veterinarian and may vary greatly depending on the situation.
Rectal exams can help determine the severity of a colic case. Some impactions may be felt, the portion of intestine involved can be determined, and the amount of gas in the intestine can often be evaluated. Performing a rectal examination is not without risks and whether or not it is indicated depends on the circumstances of the colic.
Horses with colic pain are under stress and this stress can lead to fluids being shifted from their blood into their intestines. This is frequently why they become dehydrated and need fluids to prevent the colic from progressing and to help them get their intestines working in a normal fashion again. They also support the patient until the colic has passed. Fluids can be given via a stomach tube or by an IV catheter. Intravenous fluids are one of the most important therapies for more horses with more serious colic.
Some combination of the above therapy will bring >95% of horses with abdominal pain through it just fine. However, sometimes the cause of the colic is such that fluids and medical therapy will not resolve the source. There are many causes of this more serious form of colic. The most common ones seen in Central California involving the large intestine are displacements, torsions (“twists”), and feed or enterolith impactions. Colics involving the small intestine in our area are typically more serious and may be from a fatty tumor that wraps around the intestine, or the small intestine being trapped and it’s blood supply cut off. These are the cases that often need surgery to physically relieve the obstruction or to mechanically replace the intestine back in its proper alignment. If a segment of the intestine has lost its blood supply for more than several hours, the affected portion may need to be removed and the healthy ends attached, or a bypass performed.
Colic surgery is needed in these 5% or so of overall colic cases to give the best chance of success. The first obstacle to overcome with a horse during colic surgery is the ability to correct the problem. There are some instances when the exploratory reveals a hopeless situation. However, more than 80% of horses with successful colic surgeries will make it home. This is a substantial improvement over the past several decades and due to advances in anesthesia, surgical techniques, and aftercare. Abdominal pain caused from the small intestine tend to be more serious than ones caused by the large intestine and are typically more expensive to manage due to the drugs they require during surgery and aftercare. The vast majority of horses discharged from colic surgery will lead totally normal lives several months later. When trouble happens following colic surgery it can be from the inability of the intestine to regain normal function (“ileus” is the name for this), diarrhea, laminitis, and infections of the incision, etc. Huge advances have also been made in recent years with the management of these complications.
Not everyone considers colic surgery a viable option for their horses due to previous experience, cost, or patient’s age etc. I think it is a good idea to make that determination periodically because the decision can often be hard to make in the middle of the night under stress. Medical insurance is actually very affordable and should be emphasized for family “pet” horses as much as in expensive performance horses. Care Credit® ((1-866-893-7864) is a company that offers a very reasonable payment plan for pet owners through many veterinarians.
The age of patients undergoing colic surgery is less of a concern due to the same advances listed above. Many horses in their late twenties still undergo colic surgery on a regular basis. As a horse approaches his/her twilight years, when to draw the line with regards to whether or not a patient would get surgery for colic is an individual decision. Part of the job of your veterinarian is to assist you with guiding you through that decision process.
In closing, most horses with colic will respond to simple medical management at the farm, if they do not, transportation to a hospital may be needed for further evaluation or treatment. Colic surgery has made huge advances over the past several decades for those rare cases that do not respond to simple medical therapy.