2019 Havemeyer Workshop Panelists Focus on Equine Colic
Each year the Dorothy Russell Havemeyer Foundation hosts a handful of workshops on important horse health topics; in August 2019 researchers tackled equine colic. A panel of four experts answered audience questions about colic-related issues at a table topic session reviewing this workshop during the 2019 American Association of Equine Practitioners Convention, held Dec. 7-11 in Denver, Colorado.

The panel included Frank Andrews, DVM, MS, Dipl. ACVIM, of Louisiana State University; Barbara Dallap-Schaer, VMD, Dipl. ACVS, ACVECC, of the University of Pennsylvania; Michelle Barton, DVM, PhD, Dipl. ACVIM, of the University of Georgia; and workshop organizer Diana Hassel, DVM, PhD, Dipl. ACVS, ACVECC, of Colorado State University.

Oral and Rectal Fluids

Sometimes practitioners provide oral fluids to horses suffering from impaction colic, especially if they suspect dehydration as a contributing factor. Veterinarian attendees expressed interest in what the panelists add to these fluids. While vets often administer mineral oil, the panel agreed that its greatest benefit is as a marker for liquid passage through the gastrointestinal (GI) tract. Some panelists mentioned administering 5 liters of balanced electrolyte fluids once an hour for five hours. If the impaction is due to sand, and the sand is moving, they recommended administering Epsom salts and psyllium.

Discussion then turned to administering fluids rectally. The panel agreed this can be beneficial in some cases, especially if clients can’t afford for the veterinarian to administer intravenous fluids or other treatments. Anecdotally, some panelists have found continuous rectal infusion of tap water more beneficial in some cases than oral electrolytes. Partially used 5-liter fluid bags are particularly useful as a fluid source for rectal administration. One clinician in the audience said his clinic keeps these fluid bags specifically for this purpose. Take caution, the panelists said, when administering rectal fluids, as there is the potential for rectal tears.

Non-Steroidal Anti-Inflammatories (NSAIDs)

Next the veterinarians discussed NSAID use, specifically whether its negative impacts on mucosal healing were worth the risk. Panelists agreed that while NSAIDs can compromise mucosal health and repair, the benefits of controlling pain outweigh the risks, because pain reduces GI motility. COX-2 specific inhibitors such as firocoxib can be particularly beneficial in small intestinal inflammation cases such as postoperative resections or duodenitis/proximal jejunitis, the panelists said.

Gut Motility

When a patient needs increased gut motility—such as during impactions, after colic surgery, or when in pain—Andrews said he places an apple-flavored bit in the horse’s mouth. Having the horse chew on a bit stimulates motility and has resulted in shorter reflux durations in some postoperative colic cases. chew on the bit for 15 to 30 minutes every six hours. Researchers are currently evaluating the effect of bit chewing on particle movement through the digestive tract (total transit time). Bit use and chewing might stimulate small intestinal motility in horses with small intestine ileus after abdominal surgery, he said. Doctors take a similar approach in human patients with postoperative ileus using chewing gum.

On the topic of motility, the audience returned to the topic of psyllium, asking whether it’s appropriate for impaction cases with reduced small intestinal motility. The panelists agreed that veterinarians should give nothing if small intestine motility is reduced. Again, in cases of impaction due to sand, veterinarians should administer psyllium, but only after the colic has subsided. At this point, the veterinarian can administer it daily via nasogastric tube until the sand is seen clearly moving out the digestive tract.

Fecal Water

Chronic fecal water, in which horses pass water either with their feces or after defecating, is another common problem veterinarians see. The panel offered no magic bullets for this problem; however, they engaged in a lively discussion about ingredients in oral supplements and feeds that might help maintain horses’ mucosal lining. Attendees showed particular interest in supplementing with encapsulated butyrate. This short-chain fatty acid promotes the growth of tissues lining the gastrointestinal tract and might help reduce leaky gut incidence. Leaky gut occurs when the tight junctions between intestinal lining cells are disrupted, creating gaps that allow molecules to pass between the gut and the bloodstream. Butyrate is an end product of fiber digestion, and feeding psyllium might naturally result in hindgut butyrate production.

Transfaunation

In cases of hindgut disruption, veterinarians sometimes perform transfaunation, in which they administer feces from a healthy horse as a slurry via nasogastric tube to an affected horse in hopes of populating the hindgut with beneficial bacteria. Attendees asked whether this practice would benefit horses suffering from colitis (inflammation of the large colon, aka large intestine) . The panelists said no well-controlled studies on this technique currently exist; however, the technique might benefit some cases.

Hand-Walking Colicky Horses

Hand-walking is popular practice among horse owners when dealing with actively colicking horses. The panel agreed that hand-walking is generally a good idea but offered some cautions. First, Hassel advised that you need to know whether the condition is colic, because other conditions such as botulism might produce similar symptoms, and hand-walking in these cases is contraindicated. Second, colicking horses shouldn’t be walked to exhaustion. In Andrews’ clinic, horses with medically managed colic are walked every four hours. However, others on the panel walk horses for five minutes every two hours.

Acupuncture

The session ended with a discussion on whether acupuncture might benefit horses suffering from impaction colic. Andrews said that despite initial skepticism, he has had horses that were showing little progress pass manure quite quickly after  acupuncture treatment. He said he now uses the practice often in cases of pelvic flexure impaction and postoperative ileus. Typically, horses need more than one acupuncture treatment  daily for several days. He cautioned that he doesn’t have scientific data as to whether acupuncture is more effective than traditional approaches, because it is difficult to get enough cases to conduct a controlled study. Additionally, acupuncture isn’t useful for surgical colics except to relieve pain, he said. Audience members shared that they use acupuncture for refractory cases that are also refluxing and that electroacupuncture might be more useful in some cases.

Take-Home Message

Colic continues to be the No. 1 killer of horses, but  researchers are actively  working to improve prevention and treatment (and, therefore, prognosis) for many forms of colic. Panelist take-homes from the session included:

  1. Colicking horses benefit from oral, intravenous, and in some cases rectal fluid therapy.
  2. Mineral oil given via a nasogastric tube to colicky horses is a good marker for liquid passage through the GI tract.
  3. Veterinarians should use COX-1 inhibiting NSAIDs (flunixin meglumine, etc.) with caution for colicking horses, because the drugs might inhibit tissue repair. Specific COX-2 inhibitors such as firocoxib might offer a good alternative for pain control in some colic patients.
  4. Light hand-walking is beneficial for horses with colic; however walking to exhaustion is contraindicated.
  5. Complementary medicine, such as acupuncture, might benefit some horses with impaction colic by stimulating motility or reducing pain.