Veterinarians ensure a healthy future
Like any neonate, a newborn foal depends on its mother's milk as its primary source of nutrition for the first few months of life. According to the National Research Council (NRC) Nutrient Requirements of Horses 2007, foals begin to suckle within one to two hours of birth.
Thoroughbred foals nurse about 10 times an hour for the first day for about 60 to 80 seconds at a time. For the first month, a Thoroughbred foal suckles about 45 minutes daily, with milk consumption at about 15 kg/day. At first, feral neonates have been noted to nurse 6 to 8 percent of the day, decreasing to about 2 percent by 8 weeks of age.1
The foal's changing GI anatomy
A newborn foal's gastrointestinal tract is quite different from that of an adult horse. In a foal's first month of life, the small intestine is the site of most growth, growing in both length and diameter, which increases the surface area of the villous surface for the digestion and absorption of the milk meals. The large colon plays a minor role. During this first part of a foal's life, the small intestine is the absorptive surface for its liquid diet.
"They really don't have enzymes to digest any of the other foods yet, so lactase is the prominent enzyme," Paradis says. "At 2 to 3 months of age, they get maltase, which helps digest some of the other things they might consume at that age, such as creep feed or small amounts of forage. At 4 months old, maltase takes over, and the lactase decreases."
Although owners want to have some food out so that the foals can recognize what hay, grain and other feedstuffs are, foals primarily learn feeding behavior from their dam, according to Paradis. At first though, they are not going to get much of any other nutrition except from milk, so it's important that they have a good source of milk.
During the second month of life, a foal begins to develop the cecum and the large colon as organs of digestion. However, nutritionally, the foal still depends on mare's milk as the primary source of nutrition. Over the next three to five months, the cecum and large intestine enlarge and begin to populate with microorganisms that assist in breaking down the structural elements of fibrous feeds.