Colostrum is the first milk that a mare produces after foaling. It is particularly rich in antibodies, which provide immunity for newborn foals.

Foals are born without a fully developed immune system and rely on a passive transfer of antibodies from their dam to help build their immune defenses. Consuming enough high-quality colostrum in the first 6 – 12 hours of life is critical for the foal’s health and survival.

Colostrum contains antibody proteins called immunoglobulins and other factors, which help combat diseases that could otherwise be deadly for foals.

Foals that do not get enough high-quality colostrum are at greater risk of infections, such as diarrhea caused by pathogens. If your foal cannot be nursed for any reason, donor colostrum should be fed to support immunity. Another option is to infuse equine plasma directly into the circulation to deliver antibodies.

You can determine whether your foal has consumed adequate colostrum with an IgG test from your veterinarian to measure the immunoglobulin concentration in your foal’s blood.

Importance of Colostrum for Foals

Foals are born with limited immune defences. They do not receive any immunity from their dam while in the uterus. [1]

When a foal is born, she primarily relies on colostrum from her mother to obtain protection from common diseases and start to develop an immune system. [2]

Colostrum is rich in several components including hormones, growth factors and antibodies. Many of these components support immunity and gut health, such as insulin-like growth factor, lysozymes, lactoperoxidase and lactoferrin. [5]

This first milk also contains high levels of vitamins and minerals, especially vitamin A.

Colostrum is also a source of oligosaccharides and essential fatty acids, which have been shown to promote gut development and improve thermoregulation (the ability to maintain a stable body temperature). [3][4]

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Antibodies

The antibody levels in colostrum are 100 times higher than in mature milk. These antibodies provide newborn foals with early protection from harmful bacteria and contagious diseases.

Immunoglobulins are the main antibodies in milk. They are large bioactive molecules composed of short and long polypeptide chains. The three most abundant types are:

  • immunoglobulin G (IgG)
  • immunoglobulin A (IgA)
  • immunoglobulin M (IgM)

Newborn foals have specialized cells in their digestive tract to accommodate these large molecules, allowing them to absorb the immunoglobulins in colostrum.