My Horse Has Diarrhea and Won't Eat—Now What?

Supportive care and dietary management are paramount for positive outcomes in acute colitis cases

When horses develop diarrhea, they don’t have to dart frantically to the loo like humans do, but it’s still a veritable mess. And while humans often recover uneventfully after a few days of TLC, diarrhea in horses can rapidly develop into a full-fledged, life-threatening emergency.

A primary cause of diarrhea is colitis, which is inflammation of the colon (large intestine). Complications associated with colitis develop quickly—usually within about 72 hours of disease onset—and can include severe edema (fluid accumulation in the lower limbs and abdomen), thrombophlebitis (blood clots), rectal prolapse, and the dreaded hoof disease laminitis.

“Prompt veterinary intervention and early referral to an equine hospital is always recommended for colitis cases, rather than a wait-and-see approach,” says Luis (Memo) Arroyo, Lic. Med. Vet., DVSc, PhD, Dipl. ACVIM, an associate professor at the University of Guelph’s Ontario Veterinary College, in Canada.

Even with platinum-level care and treatment, about 30% of horses succumb to colitis. If horses become dehydrated or anorexic (they’re reluctant to eat), their condition declines rapidly—within about 72 hours of the first clinical signs.

A Ticking Time Bomb

There’s more than one way to manage a colitis case. Therapy might include: 

  • Treatments to stabilize the cardiovascular system (e.g., fluid and electrolyte administration);
  • Addressing low blood protein levels in diarrheic patients (e.g., plasma ­transfusions);
  • Neutralizing the effects of toxins in the blood—endotoxin is released by Gram-negative bacteria after they pass through the gut wall and are vanquished by immune cells—or removing them from the gastrointestinal tract (e.g., administering low-dose non-steroidal anti-inflammatories, intestinal support products such as di-tri-octahedral smectite [Bio-Sponge], respectively);
  • Restoring the intestinal microbiome (e.g., probiotics, fecal transplant); and
  • Preventing equine gastric ulcer syndrome (e.g., gastric protectants, proton pump inhibitors) and laminitis (e.g., ­cryotherapy [because colitis is associated with systemic inflammation, it can cause the tissues that support the coffin bone within the hoof capsule to become inflamed and fail]).

“Every case is different, but management typically includes intensive fluid therapy and some form of antimicrobial, depending on the possible causative agent,” says Rodney Belgrave, DVM, MS, Dipl. ACVIM, staff internist and director of the internal medicine department at the Mid-Atlantic Equine Medical Center, in Ringoes, New Jersey. “The cornerstone of treatment in all of these cases, regardless of the cause, is the use of anti-­inflammatory drugs to ameliorate the effects of the endotoxemia on the body and lessen the risk of laminitis. Cryotherapy—icing of the feet as a prophylaxis (preventive method) for laminitis—is also now universally employed.”

In addition to administering medications, it’s critical you address the horse’s nutritional needs for a positive outcome.

Feeding To Heal

“Early nutritional intervention provides the patient with the ‘dietary resources’ needed for healing and expediting the recovery process,” says Gary Magdesian, DVM, Dipl. ACVIM, ACVECC, ACVCP, CVA, the Roberta A. and Carla Henry Endowed Chair in Emergency Medicine and Critical Care at the University of California, Davis.

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