Meconium is the first faeces passed by a foal and is recognisable by its dark color and firm consistency. The meconium consists mainly of secretions and dead cells from the foal’s intestinal tract, accumulated during fetal development.
In a normal foal, meconium starts passing within the first 12 hours and has often passed within 24 hours. In many foals, meconium may start passing shortly after their first milk intake. Milk intake and light physical activity promote the passing of meconium.
Meconium retention is the most common cause of straining, colic and bloating in the newborn foal. Affected foals are often seen straining and swishing or raising their tail.
The condition affects colts more frequently, possibly because they have a narrower pelvis compared to fillies.
A commercially available fleet enema can be given shortly after birth to assist in expelling the meconium. It can also be administered to foals with mild symptoms, but over-use should be avoided as it can cause electrolyte imbalance.
Short light exercise may also aid in meconium passing. However, in foals with persistent signs, for example those that stop nursing or get severely bloated, immediate veterinary attention is required.
In most cases the meconium impaction can be solved using more potent enemas, pain killers and fluid therapy, but sometimes more invasive measures such as surgery are needed.