Equine colitis: Causes, consequences and management challenges for veterinarians

Equine colitis: Causes, consequences and management challenges for veterinarians

Strategies on fighting this all-too-common and life-threatening condition in horses.
Nov 01, 2012

Paynter, a 3-year-old colt, fought down the racetrack's lane, just missing the win by a neck to Union Rags at the Belmont Stakes on June 9. On July 29, he fought again, this time pulling away from the rest of the field at the top of the stretch to commandingly win the $1 million Haskell Invitational.

But sadly those races would not be his biggest fights. After he contracted a fever and pneumonia, Paynter was sent to the Mid-Atlantic Equine Medical Center in New Jersey and administered fluids and antibiotics on July 31. Shortly thereafter, he was shipped to Belmont Park in Elmont, N.Y., to recuperate and then to Saratoga Race Course in Saratoga Springs, N.Y., for a shot at the late summer derby, the Travers Stakes, Aug. 25.

For the win: Paynter, a thoroughbred shown here winning the Haskell Invitational at Monmouth Park in Oceanport, N.J., has been diagnosed with the debilitating disease equine colitis, and the fight to conquer this condition has begun. (BILL DENVER/EQUI-PHOTO)
Again showing signs of illness on Aug. 28, he was sent to the Upstate Equine Medical Center, Schuylerville, N.Y., and was placed under the care of Laura Javsicas, VMD, DACVIM. Paynter was treated aggressively with intravenous fluids and plasma on a 24/7 regimen to try to combat a bout of severe colitis. On Sept. 2, Paynter began to show signs of laminitis, a common complication of colon inflammation. As of Sept. 12, Paynter is stable and still being treated.

Paynter's story is an illustration of the devastating effects equine colitis and its associated complications can have on affected horses.

Equine colitis overview

According to Douglas Thal, DVM, DABVP, Thal Equine LLC, Santa Fe, N.M., the equine digestive tract is a complex and fragile system that is easily disrupted. One sign that the colon is disturbed is the development of diarrhea, from mild to severe—even life-threatening. Once colon health is disrupted, its ability to carry out the normal functions of digestion and absorption are critically affected.

"Serious colitis causes severe diarrhea, which accounts for huge water loss, and can cause rapid loss of fluid from the circulatory system," Thal says. "This leads to a vicious cycle of low blood pressure and reduced blood flow to vital organs and circulatory shock, which can quickly result in death if untreated."

Colitis disrupts the integrity of the mucosa. Once a horse is affected, the ability of its colon to absorb water and nutrients—the colon's normal function—is compromised. In addition, major shifts take place with respect to the bacterial population needed for normal gastrointestinal (GI) function.

GI inflammation can take several forms. It can occur as segmental disease, limited to one section of the GI tract, or as more diffuse, nonsegmental disease, says K. Gary Magdesian, DVM, DACVIM, DACVECC, DACVCP, professor at the University of California-Davis School of Veterinary Medicine. Magdesian notes that the illness is called:

  • Colitis when restricted to the large colon
  • Typhlocolitis if the cecum also is involved
  • Enterocolitis if the small intestine is included
  • Enteritis when it's limited to the small intestine
  • Gastritis if the inflammation affects only the stomach
  • Gastroenterocolitis if the entire GI tract is involved.

In general, the younger the horse, the more likely it is to have primarily small intestinal involvement. But even mature horses can have any of these forms, including diffuse disease, disease limited to the small intestine or disease limited to the large colon.