Meconium is the first fecal material produced by a newborn foal. Composed of cellular debris, amniotic fluid and intestinal secretions, it is formed during the time the fetus is in the uterus. The foal normally passes it within 30 minutes of the foal's first suckling or approximately two hours after birth.
Meconium retention occurs when the foal fails to pass the meconium and begins to experience abdominal pain. Normal meconium is generally dark brown and forms small balls, but in meconium retention, the fecal consistency is dry and hard. The total amount of meconium is a little over one percent of the foal's body weight or 1 pound in a 100 pound foal. If you line the balls up, you should have a line about 18 inches long.
Meconium retention is seen in the first day or two of life. In many instances, the cause of meconium retention cannot be found. It has been suggested that lack of oxygen at birth may affect intestinal motility. Hydration status may also effect the passage of fecal material. If the foal is a little dehydrated then the meconium balls could become hard. Colts appear to be more often affected than fillies. The male foal has a narrower pelvis and a convex pubis, which may predispose it to impaction.
What to Watch For
Other problems can present with similar clinical signs. Ruptured bladder may also result in signs that are mistaken as straining to defecate when they are actually straining to urinate. When straining to urinate, the foal hollows his back. Atresia coli will present with similar signs. The most consistent finding in the disease is that affected foals don't pass meconium following repeated enemas. Lethal white foals also present with no meconium production and colic. These foals are white with blue eyes. They are the result of the breeding of two overo paint parents.
Your veterinarian will examine the foal to determine the cause for the colic. Generally the foal's vital signs are within the normal limits. This examination will probably include a digital rectal examination of the foal. This involves gentle probing of the rectum with a lubricated finger. In meconium impaction, your veterinarian may feel small hard fecal material. It is important not to try and pull these fecal balls out. This could damage the delicate lining of the rectum. In most cases the history, clinical signs and the absence of adequate meconium leads to the diagnosis of meconium retention.
Meconium retention is best treated with the use of several types of enemas. Human phosphate enemas (Fleet®) are effective in treating mild meconium impactions. Enemas of warm soapy water (1 liter or quart in volume, using a mild hand soap) have been effective in relieving more persistent impactions. These enemas may be given using a soft rubber tube. Enemas must be done gently to prevent irritation and injury to the delicate rectal mucosa. Rectal irritation will cause continued straining even after the meconium has passed. Recently a newer enema concoction containing acetylcysteine that breaks up meconium has been described.
Sometimes meconium continues to be retained in the upper part of the large intestine and is not readily relieved with enemas. At this time it may be advisable to investigate the cause of the abdominal pain with an abdominal radiograph. Meconium may be seen as fecal material in the large colon, small colon and rectum. Gas distended loops of bowel maybe seen in front of the meconium. Barium enemas may also outline the meconium pellets.
If the impaction has not resolved with the use of enemas, then nasogastric intubation and administration of mineral oil (240-mls/40 kg foal) may be indicated. Mineral oil should not be administered before 18 hours of age in order to allow adequate colostrum absorption. Intravenous fluid therapy is beneficial in the dehydrated foals. Pain relief and sedation may be needed to relax the foal while the meconium is passing.
In rare cases surgical intervention may be necessary for foals that do not respond to medical therapy. Internal bowel massage with simultaneous enema or enterotomy (incision into the intestine) may be performed.
Foals should be closely watched after birth for the passage of meconium. If possible the amount passed should be noted. Foals may demonstrate some normal straining to defecate but it should be productive. If the foal becomes painful or stops nursing, you should call your veterinarian.
Some farms routinely administer an enema to foals soon after birth. This can be done using a Fleet® enema that is normally used for humans. This type of enema comes in a nozzled container. Before using this product the foal should be adequately restrained. One person should hold an arm around the front of the foal and lift the tail with the other hand, while a second person gently inserts the nozzle tip into the anus and squeezes the container. This should stimulate the bowel to evacuate its contents.
Foals should be observed following treatment for passage of meconium. This procedure should only be performed once by the owner. If it is not productive or the foal remains painful, your veterinarian should be called. CAUTION - rough handling during the administration of an enema can cause damage or perforation of the foal's rectum.