The immunoglobulin fraction in bovine colostrum is composed of approximately 70-80% IgG, 10-15% IgA, 10-15% IgM, while IgE and IgD are found in small amounts.
Local protection in the form of immuno-supplementation with bovine milk antibodies has been shown to be an effective means of providing local protection to the GI tract.
The function of these immunoglobulins (antibodies) is as follows:
IgG — predominant immunoglobulin in bovine milk colostrum; primary function is to identify and help destroy invading pathogenic microbes.
IgA — predominant immunoglobulin in human milk and colostrum; primary role is as first line of defense, protects mucosal surfaces and prevents the attachment of pathogens to them.
IgM — primary role is “first to fight;” enhances phagocytosis by destroying invading pathogens.
IgE — involved with the allergic reaction and histamine-associated allergic reaction; also involved with active defense against enteric parasites.
IgD — attached to B cells; it stimulates lymphocytes to produce antibodies by presenting antigens to them.
Laboratory analyses of both immune and growth factors from bovine colostrum indicate that they are identical to those found in human colostrum except for the fact that the levels of these factors are significantly higher in the bovine version. Bovine colostrum is actually 40 times richer in immune factors than human colostrum. For example, human colostrum contains 2% of IgG (immunoglobulin G) while cow colostrum contains 86% of IgG, the most important of the immunoglobulins found in the body.