Colic and Digestive Health (AAEP 2006 Wrap-Up)

Each year the AAEP awards an outstanding practitioner the Frank J. Milne trophy to recognize a lifetime of service in a particular area of expertise. The 2006 designate was Nat White II, DVM, MS, Dipl. ACVS, the Jean Ellen Shehan Professor and director of the Marion duPont Scott Equine Medical Center at the Virginia-Maryland Regional College of Veterinary Medicine, and chairman of the AAEP Foundation Advisory Committee. White has spent a lifetime in service to the horse, specifically in researching and treating colic.

This year's presentation was sponsored by the AAEP Foundation ( and Platinum Performance (

White has authored more than 150 articles and 35 book chapters, in addition to writing several books, including Equine Acute Abdomen and Handbook of Equine Colic, as well as the surgical texts Current Techniques in Equine Surgery and Lameness and Current Practice of Equine Surgery. White, a former director-at-large of the AAEP, is a past president of the American College of Veterinary Surgeons (ACVS) and has served as director of the ACVS Veterinary Symposium since 1997.

His presentation, "Equine Colic: A Real Pain in the Gut," was attended by nearly 3,000 industry representatives and equine practitioners. White recounted a timeline of understanding equine colic using case examples from his clinical experience and research. He used computer-generated videos done in collaboration with a team at the University of Georgia to show intestinal diseases and rectal examinations.

White has spent a career caring for horses with all types of problems, but the mystery of colic has never lost its appeal.

"I remember when I was at UC Davis doing my residency and had 15 surgical colics in one month, and 14 died," recalled White. "The surviving horse came back and died with liver disease. I figured there had to be a better way."

Then he met Jim Moore, DVM, PhD, and Doug Byars, DVM, Dipl. ACVIM, who started the Bolshoi Colic Research Program at the University of Georgia. That meeting focused White's interest in colic.

White's complete presentation can be found in the AAEP's convention proceedings. The Glass Horse project that created the animated videos was founded by Moore with support of American Live Stock Insurance. For more on the Glass Horse visit

Colic Research and Risks

Colic, defined as any abdominal pain, has resulted in the deaths of horses throughout recorded history, stated White. In fact, it is second only to old age as the number one cause of equine deaths in the United States today. White said it is one of the most difficult diseases to study since there are so many things that can cause colic.

White and others have studied the incidence of colic. He said out of 100 horses in a population, four to 10 cases of colic can be expected per year. That number can vary widely between farms, ranging from zero to 35 cases per 100 horses per year.

About 10-15% of colic cases happen in horses that have had clinical signs of colic before, with some horses having two to four episodes per year. Fortunately, a majority of colic cases (80-85%) are termed "simple" because they either resolve by themselves or can be treated medically.

A small portion of colic cases (2-4%) require surgery. Large colon torsion is the most common portion of the bowel to be struck with strangulation obstructions, with strangulations of the small intestine causing the highest fatality rate.

In one study based on a sample of 28,000 horses in 1998:

  • Average loss of use due to colic was two to three days;
  • Value of horses lost due to colic in the United States was about $70 million; and
  • Total cost of colic to the U.S. industry was about $144 million.

White said another study estimated the number of colic surgeries in the United States annually is 12,000-24,000 cases, or possibly as many as 2.7 colic surgeries per hour.

While parasites were a major cause of colic earlier in the history of the horse, they became less important with the creation of modern anthelmintics. But White said as parasites become resistant to those drugs, there could be more colic caused by parasites in our horses' futures.

In 1966 the first work was done looking at the strangulated colon at Colorado State University. By 1970 there was more surgery being done to try and correct severe colic causes (twists, displacements, intussusceptions--when the gut telescopes back into itself).

"In 1978 Bana­mine came along and made us look at what was happening in the gut," said White. That was followed by research into ischemia reperfusion, endotoxic shock, and epidemiology. Discovering there were specific risk factors for colic helped veterinarians and horse owners begin to prevent colic, although not all of the answers have been discovered.

According to research findings, change in diet or feeding of large amounts of grain (greater than 5 kg/day in adult horses) increases the risk of colic by 6.3 times, and feeding concentrates at a rate of 2.5-5 kg/day increases colic risk by 4.8 times, noted White. Here are some other findings of colic associations:

  • It has been reported that some breeds are more susceptible to colic (Arabians, Thoroughbreds, Standardbreds, gaited horses, and Warmblood stallions);
  • Middle-aged horses are at higher risk for simple colic;
  • Older horses with colic are more likely to need surgery;
  • Weanlings and yearlings are more likely to have ileocecal (at the junction of the small and large intenstines) intussusceptions;
  • Older horses (greater than 12 years) are at a higher risk of developing strangulating lipomas (fatty benign tumors that can develop around the intestines);
  • Male horses and older horses have a slightly higher risk of entrapment of the small intestine in the epiploic foramen (the passage connecting the two sacs of the abdominal cavity;
  • Horses with sudden decreases in activity (such as strict stall confinement) are at greater risk of cecal and large colon impactions.
  • Location and management can be associated with colic (i.e., enterolith (intestinal concretion) formation related to diet and geographic region, such as California);
  • Cribbing is associated with increased risk of simple large colon obstruction and entrapment of the small intestine in the epiploic foramen;
  • Tapeworms are associated with ileocecal intussusception or cecocecal (pertaining to the cecum) intussusception;
  • Pregnant mares have an increased risk for colon displacement or volvulus intestinal obstruction due to a twisting or knotting of the bowel);
  • Ulcers can predispose a horse to colic;
  • Transportation has been linked with an increased colic risk;
  • Weather has been found to change management techniques, which resulted in feeding/turnout changes that are associated with colic.

More, and More

The information distilled above was only a small portion of White's presentation. He also covered Intestinal Response to Injury; Diagnosis: Determining the Need for Emergency Abdominal Surgery; Treatments for Colic, Prognosis and Prevention; and Future Research. More on these subsets of his talk will be presented in the online version of the AAEP Wrap-Up.

Down the Hatch

Veterinarians at Oregon State University have developed a method to get valuable calories into anorexic horses or those unable to eat normally. For horses with mouth or throat injuries, this method can be used to provide the horse's complete daily ration of feed and water. Shannon K. Reed, DVM, a surgery resident at Oregon State, explained the procedure.

The horse's complete daily ration of feed is weighed, dumped into a bucket, covered with enough water to make it crumbly, and soaked for about 30 minutes. The ration is divided into three or four small meals and stored in plastic bags.

At feeding time, the ration is mixed with one ration of water to create a thin gruel. A nasogastric tube is used to place the gruel in the horse's stomachso.

Reed called the method easy and affordable, and said that providing sufficient calories helps speed the healing process.

For feeding, the veterinarian mixes this ration with one ration of water to create a thin gruel. He places large-bore tube (about 4 cm in diameter) into the gruel and connects it to the bilge pump, then he inserts a nasogastric tube in the horse's stomach and connects that tube to the pump's outflow valve. The pump suctions the gruel out of the bucket and into the horse's stomach via the nasogastric tube.

Reed called the method easy and affordable, and said that providing sufficient calories helps speed the healing process.

Colic: An Overview for Horse 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%.

Types of Colic

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

  • 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.
  • Contact your veterinarian at first signs of colic.
  • 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.
  • Don't treat the horse yourself--especially do not give Banamine (flunixin meglumine) in the muscle! "I have seen three horses that by the time they got to clinic, their colic was over, but they died from the myositis (voluntary muscle inflammation)," recalled Freeman. "It's not a risk you want to take."
  • Don't 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. "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. "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 This does prevent injury to horses, people, or property, he said. However, walking a horse excessively might mask signs of deterioration; 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. "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.

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. 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.

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

Prevent the Problem

So what can an owner do to prevent colic in his/her horses?

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.

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