Colostrum Colostrum Colostrum (known colloquially as beestings, bisnings or first milk) is the first form of milk produced by the mammary glands of mammals (including many humans) immediately following delivery of the newborn. Most species will generate colostrum just prior to giving birth. Colostrum contains antibodies to protect the newborn against disease. In general, protein concentration in colostrum is substantially higher than in milk. Fat concentration is substantially higher in colostrum than in milk in some species, e.g. sheep and horses, but lower in colostrum than in milk in some other species, e.g. camels and humans. In swine, fat concentration of
Immunoglobulin A is the most prevalent and is also called "secretory IgA" (sIgA). sIgA is the main immunoglobulin found in mucous secretions, including tears, saliva, sweat, colostrum and secretions from the genitourinary tract, gastrointestinal tract, prostate and respiratory epithelium. It is also found in small amounts in blood. The secretory component of sIgA protects the immunoglobulin from being degraded by proteolytic enzymes, thus sIgA can survive in the harsh gastrointestinal tract environment and provide protection against microbes that multiply in body secretions. sIgA can also inhibit inflammatory effects of other immunoglobulins. IgA is a poor activator of the complement system, and opsonises