Colic in Horses: An Overview for Owners

What's the one word that strikes fear into the hearts of all horse owners? Colic. It can strike any horse at any age for a myriad of reasons--there's impaction colic, gas/spasmodic colic, strangulating colic, and many other versions. At the recent Healthy Horses Workshop, an owner education session held Dec. 2, 2006, in San Antonio, Texas, in conjunction with the 52nd annual American Association of Equine Practitioners Convention, colic was the first topic of discussion.

According to a 1998 USDA National Animal Health Monitoring Study, colic was second only to old age as leading cause of death in horses over 30 days of age, said David Freeman, MVB, PhD, Dipl. ACVS, professor/associate chief of staff and chief of the large animal surgery department at the University of Florida. Colic ranked second and third in causing days of lost use and morbidity (illness), respectively.

But colic treatment success continues to improve; Freeman noted that while from 1968-1986, 49% of horses undergoing small intestinal surgery died, in 2005 that number was down to 12-18%.

"We are constantly learning about this disease," he said. "We know a lot of things, but not all we'd like to know.

Types of Colic

Freeman noted that the overall incidence of colic is about 10-36%, according to the 1999 Handbook of Colic by White and Edwards. This breaks down into various types of colic as follows:

  • Mild idiopathic (of unknown cause) colic: 83%. "I suspect that most idiopathic colics are impactions," Freeman commented.
  • Impaction: 7%. "Those related to diet are mostly from fine-textured coastal Bermuda grass, particularly in the Southeast," he reported.
  • Gas/spasmodic colic: 4%. "Gas is associated with all colics," he noted.
  • Intestinal strangulation (twisting): 3%. "Strangulations require surgery," he stated.
  • Gastric (stomach) rupture: 2%
  • Enteritis (intestinal inflammation): 1%. "Enteritis mostly manifests as diarrhea, but there are other manifestations as well," Freeman said.

Colic can result from odd non-food things horses eat as well. "Horses are supposed to be picky eaters," he commented. "But all of us who do colic surgery have these little trophies to disprove that theory (part of a lead rope, sand, gravel chunks, etc.). One horse I treated ate nipped-off clinches (pieces of horseshoe nails left after farriers clinch and clip the nails when setting shoes) from the ground and enteroliths (solid rocklike masses in the gut) formed around it. These can be as big as a football, but usually they're softball size."

Prognosis varies with the type and location of the colic. For example, Freeman reported that lesions of the large colon have a better prognosis than those of the small intestine, and the prognosis for a strangulated (twisted) intestine is not as good as that for a non-strangulating lesion.

You Can Fight Colic

Freeman described these steps to helping your horse survive colic:

  • Establish a solid working relationship with your veterinarian, preferably before the horse gets sick. Include the veterinarian at the referral hospital if you can, he recommended.
  • Record observations and a chronology of events. Observe your horse when he's normal so you can recognize the abnormal. It's not a bad idea to keep a log of observations if you notice a change in behavior.
  • Contact your veterinarian at first signs of colic.
  • Don't treat the horse yourself--especially do not give Banamine (flunixin meglumine) in the muscle! Myositis (voluntary muscle inflammation) is one complication. "I have seen three horses that by the time they got to clinic, their colic was over, but they died from the myositis," recalled Freeman. "It's not a risk you want to take."
  • Do not repeat Banamine doses frequently. The full dose should only be given once or twice a day. Kidney damage can result because the horse is often already dehydrated from not drinking. "The odds are low, but when it happens, that's it. You can't bring the kidneys back," said Freeman. Repeated doses can mask signs of pain from colic.

Freeman also discussed the value of several on-farm treatment and management practices for colic:

  • Painkillers "We have all these great painkillers now, but signs of pain are what you use to see how the horse is recovering or not," Freeman cautioned. "Don't say your horse is a baby about his clinical signs. They're a lot tougher than you think. Some horses show little pain even with severe problems. But if they paw, look at their flanks, roll, etc., after getting painkillers, that's bad."
  • Walking does prevent injury to horses, people, or property, he said. However, walking a horse excessively might mask signs of deterioration, he warned; stop frequently to assess the horse's demeanor. If he needs surgery, walking won't help.
  • Feed/Water Do not feed horses until colic is resolved, as this makes it worse, he warned. "I've seen a lot of really sick horses still eat," he said. "They're amazingly tough; far tougher than we are. It's not unusual for a colicking horse to have a good appetite." He also noted that water might not be recommended if the horse's stomach is already distended; adding water might rupture the stomach. Your veterinarian can examine the horse and tell you whether he should have water.
  • Oral medications Don't give these to a colicky horse, recommended Freeman.

Surgical vs. Medical Colic

Freeman said "referral" to a veterinary hospital for a colic case might include any of the following scenarios:

  1. "Your vet has decided that colic is too severe to be managed on the farm. The horse needs to be monitored and observed closely. He might not need surgery--maybe 50% of horses referred don't need surgery. Perhaps it's the therapeutic trailer ride," he said with a smile.
  2. The horse might need surgery, more intensive pain management, and/or more advanced diagnostic methods.
  3. You can't watch the horse forever; you might have to go to work or somewhere else, and if he's at hospital, someone will be watching him continuously.

"We're probably 80% accurate on making that choice of whether a horse should be referred," he reported. Medical colics (those that can usually be managed without surgery) include impactions from feed material and colics due to inflammation (from enterocolitis, or inflammation of the small and large intestines; colitis, inflammation of the large intestine only; or proximal enteritis, inflammation of the upper gastrointestinal tract). Surgical colics include strangulations, displacements, and nonresponsive impactions.

Evaluating Colicky Horses

"When we work up a colicky horse, we get a history, what drugs he's been given and when (this is very important), do a physical exam, and check his cardiovascular system (this is critical; it tells us if he's in shock)," said Freeman. "We pass a stomach tube to see if there is reflux (backflow of stomach contents via stomach tube). Fluid in the gut will back up from the obstruction all the way to the stomach, so reflux is a diagnostic test, and it helps the horse feel better. The more reflux you have, the closer the obstruction is to the stomach. We usually see reflux with small intestinal disease, but not large intestinal disease."

He said he might also test peritoneal fluid (from the abdominal cavity); bloody color means the affected gut is probably dead. That is not a good sign. Rectal palpation might also be employed, or ultrasound, which is non-invasive and can be used to evaluate the whole abdomen to a depth of about six inches or so. Ascarids, intussusceptions (telescoping of one portion of intestine into another), and a variety of intestinal changes can be seen with ultrasound, he said.

Some bowel displacements can be corrected by anesthetizing the horse and rolling him and/or using other nonsurgical treatments. However, if a diagnosis can't be reached with the aforementioned procedures, surgery might be used for diagnosis as well as treatment, he noted. During surgery, bowel can be replaced if it is out of position, its contents can be removed (enterotomy), and it can be cut out if it is strangulated and dead. If this occurs, the healthy bowel on either side is stitched together (anastomosis).

Some horses might need a second surgery for complications, he reported.


Endotoxemia can occur with various infections or a strangulating lesion. Freeman said that when the gut is strangulated and black, it's dead--its surface cells die and its contents, which are full of endotoxin from bacteria, can get out into the bloodstream. Endotoxin makes the horse sick and causes the most serious complications of colic.

"Endotoxin itself is not damaging, but cells overrespond to it," he explained. "Flunixin (flunixin meglumine, or Banamine) is helpful because it blocks the body's response to endotoxin. There is some evidence that flunixin might interfere with healing of the small intestine, but it is doubtful that that effect is enough to not use it in these horses until we get a better drug for treatment of pain and endotoxemia."

How do you know if a horse has endotoxemia? If you see a red ring around the tops of his gums. "We call this a toxic ring," said Freeman. "Also, some horses so depressed the owners think he's quieter and getting better. But if he's got red gums and is in shock, with his skin cold and clammy, he's got severe endotoxic shock and he is not getting better."

Surgery Aftercare

After surgery, the horse will need frequent monitoring and physical exams, possibly antibiotics, fluid therapy, pain medication, and a gradual return to hay and water. He'll be hospitalized for four to seven days, said Freeman, then he'll need 60 days of rest at home before resuming normal activity. He recommends stall rest only for Days one to 14, then stall rest with hand walking on Days 15-30. If the horse is quiet, he can be placed in a small paddock or round pen if the incision is healthy for Days 31-60.

Feeding can resume when the surgeon thinks it's safe, usually 18-36 hours after surgery, and water should be provided free choice. "The bowel doesn't recover from surgery right away; initially it has lower motility called postoperative ileus," said Freeman. "Start with feeding little handfuls of hay and see how he handles it. Watch for feces; that means the plumbing is working."

Antibiotics will often be given for two to three days to inhibit infection at the surgical site. Banamine is usually given for at least two days to inhibit pain and inflammation. Check your horse's temperature (normal is 99.5-100.5°F) and report fevers to your veterinarian. Why not give antibiotics for a longer period? They don't kill everything, said Freeman, and if you get antibiotic-induced diarrhea, you might lose your horse.

"It kills off good bacteria and the bad ones take over," he said. "I like to keep any antibiotic treatment as short as possible. Plus it's a little like showing the enemy your weapon--they get resistant. Some major hospitals have been closed because of outbreaks of antibiotic-resistant salmonella."

Most horses will be quiet from the stress of the disease and surgery, and some might lose weight. Mild colic might also occur; report this to your veterinarian.

Possible incision problems include infection and hernia. "You'll always get swelling along the incision," said Freeman. "Get the veterinarian to look at it if you're worried or if it's draining fluid. This can lead to a weakened incision and hernia. Hernias aren't life-threatening; mares have had foals with them, and horses have competed with them. Some people have killed horses because of hernias; don't do that! Some hernias even self-resolve."

Ponies vs. Horses vs. Drafts

Freeman said that light-breed horses tend to come through colic surgery better than heavy horse breeds. Why? "Everything is big, everything inside them is big, so the surgery takes longer and they're lying on that huge muscle mass for a long time--some can't get up after surgery because of muscle damage," he explained. "That's one of our challenges--improving their success rate."

But it's not simply a case of smaller is better--Miniatures and ponies have issues, too. "When they're off feed, they will mobilize fat stores (full-sized horses don't do this as much)," he noted. "They will end up with hyperlipidemia (a lot of fat mobilized into the bloodstream) and end up with liver damage, so they don't do well either. They come through surgery fine, the surgery is very easy, but because they didn't eat before or after surgery, they need to be fed via tube, IV, whatever, or they'll die from hyperlipidemia.

Life After Colic Surgery

"The first six months after surgery is the critical period, and if you get to one year after surgery, you can relax a little," Freeman said. "People think a horse after colic surgery is finished, but that's not true. We now know that many of these horses go back to very top-level performance. For example, Left Bank was a Thoroughbred racehorse who colicked as a 2-year-old and had some small intestine removed. He raced from two to five years old, and had 24 starts and 14 wins (three of them Grade 1 stakes). He won $1.4 million lifetime and set records.

"A steeplechaser named Victorian Hill had large colon torsion and resection; he raced for five years and won $296,000 after surgery," he added. "He was a leading steeplechaser at the end of his career.

"There's no longer a perception that if a horse steps on the trailer for colic surgery, he's not coming back," Freeman said.

Owner Responsibilities

Most of an owner's job involves preparation, says Freeman. He made the following suggestions:

  • If your horse is boarded, provide your contact information, assign responsibility for care decisions in your absence, provide insurance information, and establish limitations on treatment, if any.
  • Be prepared for financial obligations.
  • Be prepared for emotional trauma; think about what you'd do in this situation ahead of time to avoid the "trapped-owner syndrome." It's hard to make decisions at 3 a.m. when you can't call anyone.
  • Maintain a positive relationship with your veterinarian and referral hospital.
  • Remain educated, but keep an open mind; there are many differences of opinion on colic treatment practices.

Prevent the Problem

What can you do to avoid this mess? Minimize abrupt management and diet changes, and keep plenty of fresh water available at all times, said Freeman. Maximize grazing time, feed good-quality roughage and few concentrates, and maintain a good deworming program.

Get research and health news from the American Association of Equine Practitioners 2006 Convention in The Horse's AAEP 2006 Wrap-Up sponsored by OCD Equine. Files are available as free PDF downloads.

About the Author

Christy M. West

Christy West has a BS in Equine Science from the University of Kentucky, and an MS in Agricultural Journalism from the University of Wisconsin-Madison.

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