Watch for Meconium Impactions in Foals

Watch for Meconium Impactions in Foals

Foals with meconium impactions strain to defecate and also show signs of persistent abdominal pain.

Photo: Bonnie Barr, VMD, Dipl. ACVIM

Foaling season is upon us, and owners are preparing for the arrival of their next superstars. After a foal is born, several events must occur to ensure he or she remains healthy. One of the most important is passing meconium. This is the first feces, composed of mucus, amniotic fluid, and sloughed cells from the gastrointestinal (GI) tract. It is typically dark greenish-brown or black and ranges in consistency from firm pellets to sticky paste. Foals usually begin passing meconium in the first hours after birth and shortly after ingesting the mare’s colostrum, which acts as a laxative and a stimulator of GI motility. 

Meconium passage is generally complete within 24 hours, but it can take up to 48 hours. It is not atypical for newborn foals, standing or in recumbency (lying down), to strain considerably with an arched back when passing meconium. These attempts should be productive, however. 

Male foals and foals born after a prolonged gestation appear to be predisposed to meconium impactions, which can be classified as either high or low. A low impaction is an obstruction of the small colon/rectum at the pelvic inlet (the front entry of the pelvis). A high impaction is found earlier in the GI tract, generally at the transverse or right dorsal colon. Low impactions far outnumber more serious high -impactions. Delayed meconium passage prevents proper digestive movement, with subsequent gas/fluid distension causing abdominal pain.

Meconium, the first feces, is composed of mucus, amniotic fluid, and sloughed cells from the GI tract. It is typically dark greenish-brown or black and ranges in consistency from firm pellets to sticky paste.

Photo: Bonnie Barr, VMD, Dipl. ACVIM

In addition to straining, a foal with a meconium impaction will swish its tail frantically and show signs of persistent abdominal pain, including kicking at the abdomen and rolling. Some nurse frequently but not effectively because of the pain. They often stand under the mare’s streaming udder and have dried milk on their heads. Significant -abdominal -distension might develop if the meconium occludes the intestinal lumen (cavity) and prevents gas from passing. If your foal shows signs of severe abdominal discomfort or distension, contact your -veterinarian. 

The veterinarian will base diagnosis on the foal’s health history, clinical signs, physical examination, and other test results. Performing a digital (finger) examination might help identify fecal material at the pelvic inlet; however, a lack of fecal material does not rule out meconium retention. If you or your veterinarian suspects an impaction, you might be able to confirm it simply by administering a mild enema and observing the response. If signs of abdominal pain persist, the veterinarian should pursue abdominal radiography and ultrasonography to rule out other issues. Radiographs after administering a barium enema as a contrast medium can be very useful if other diagnostics are -inconclusive. 

Treatment varies depending on severity and duration. Careful manual removal of fecal material might be all that’s needed. Mild enemas usually soften and lubricate the feces to make their passing easier. Commercial products are available and can be effective. A safe, nonirritating enema solution consists of 500-1,000 mL of warm water with 5-10 mL of soft soap (such as Ivory). Many veterinarians recommend gravity flow retention enemas containing 4% acetylcysteine (a drug that clears mucus). Repeated enemas can irritate the sensitive rectal mucosa. If one enema does not resolve the impaction, contact your veterinarian. 

Your veterinarian may choose to administer laxatives or cathartics (which ease and accelerate defecation, respectively) via nasogastric tube, particularly if he or she suspects a high impaction and it persists despite the use of an enema. These products likely work by stimulating GI motility. Judicious use of analgesics to control pain is important. It is rare that the foal requires abdominal surgery to resolve the impaction, but this step might be necessary due to unrelenting, nonresponsive pain and/or severe gas distension. 

As with many conditions, early recognition and treatment are important for managing these impactions successfully.

About the Author

Bonnie Barr, VMD, Dipl. ACVIM

Bonnie Bar, VMD, Dipl. ACVIM, is a shareholder at Rood & Riddle Equine Hospital, in Lexington, Kentucky.

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