Late-gestation abdominal pain in mares can be a perplexing enigma, a blend of mystery and urgency

A horse of any sex or reproductive status could experience abdominal pain from gastrointestinal (GI) distress or muscle pain in the abdomen. But a pregnant mare showing abdominal discomfort could be aborting her fetus or developing pregnancy complications.

Most colics resolve uneventfully: no surgery or even fluids needed. “Abdominal pain is common in horses in general,” notes Ashley VanderBroek, DVM, Dipl. ACVS-LA, assistant professor of large animal surgery at Michigan State University (MSU) College of Veterinary Medicine, in East Lansing.

When it comes to dealing with pregnant mares, “I would say the majority of colic cases are similar to horses that are not pregnant—usually mild and resolve on their own,” VanderBroek says. However, when a pregnant mare’s colic becomes severe, it might require “prompt surgical management.”

Causes of Late-Gestation Colic

“Colic is just a term to describe abdominal pain in the horse,” VanderBroek explains. “Most of the time that’s associated with the GI tract, but it doesn’t have to be.”

“We have to think about the GI tract, urinary tract, and reproductive tract when a horse is displaying signs of colic,” adds Julie Strachota, DVM, MS, Dipl. ACT, assistant professor and director of clinical education at MSU’s College of Veterinary Medicine.

In late gestation space is scarce in the abdomen. So, in a pregnant mare experiencing abdominal pain, “some of it could just be discomfort from everything being a little bit more compressed,” VanderBroek says.

When the mare’s internal organs get compressed and displaced, diagnostics become challenging.

“It is very, very hard to call some of these ‘GI problems’ just based on palpation or based on ultrasonography,” says Ahmed Tibary, DMV, MS, DSc, PhD, Dipl. ACT, professor emeritus in the Department of Veterinary Clinical Sciences at Washington State University College of Veterinary Medicine, in Pullman