PrintColostrum is so important to a foal’s immune and digestive systems that breeders should know how to test, store and supplement it.
Within minutes of birth, a foal struggles to his spindly legs, falling and standing again until he can make his way to his mother and begin nursing. Those first tentative steps lead him to an essential element in his health—the mare’s first milk, or colostrum.
Colostrum stimulates the gastrointestinal tract, to help the foal pass his first bowel movements and eliminate the meconium, and contains a creamy fat that is high in energy and easily digested. The antibodies in colostrum provide passive transfer from the dam to protect the foal until his own immune system can start producing antibodies. Thus it is important for the foal to nurse as soon as possible after birth.
Peter Sheerin, DVM, of Rood & Riddle Equine Hospital, Lexington, Ky., said that the mare produces antibodies in response to pathogens she is exposed to in her environment.
“[That’s] one reason many farms request that foaling mares come to the facility at least 30 days prior to foaling. This will allow the mare to develop antibodies to local pathogens, to help protect the newborn foal,” he said.
Pre-foaling vaccinations also stimulate production of antibodies that will hopefully appear in a mare’s colostrum.
“Owners should vaccinate mares against diseases that might be a concern on their farm, four to six weeks ahead of the mare’s expected foaling date [in order to produce peak levels of antibodies in the colostrum],” Sheerin said.
A foal needs to consume the colostrum within the first couple of hours of life. When he is first born, the antibodies can cross the intestinal mucosa and be absorbed, but once the foal starts ingesting colostrum, the ability to absorb these large antibodies decreases.
“This does not decrease in a linear fashion, however,” said Sheerin. “Even though the absorption rate is 100 percent at birth and by 24 hours is zero, you can’t draw a straight line from 100 percent to zero and say that at 12 hours it’s 50 percent. It drops off much more quickly than that once the foal begins to nurse.”
This is nature’s way of “shutting the door” to opportunistic pathogens that might also cross through the gut lining. It’s always a race between the pathogens and the protective antibodies, so horse owners need to get as much colostrum into the foal as early as possible.
More Than Immunity
John Madigan, DVM, from the University of California, Davis, said that colostrum works in the gut to help the foal, in addition to providing the antibodies that can slip through the gut lining into the bloodstream and lymph system to stimulate systemic immune response.
“Colostrum is a natural laxative. It also contains glucose and energy from fat that gives the foal more strength to stand and nurse or deal with inclement weather [without becoming so chilled] or other stresses,” said Madigan.
Colostrum also contains IgA (immunoglobulin A), which does not cross through the gut lining; these antibodies stay in the tract to fight off pathogens that cause diarrhea. These can be helpful even after gut closure occurs and the foal can no longer absorb antibodies into the bloodstream.
In fact, Madigan recommends that horse owners hand feed the foal’s first meal before it gets up.
