Colostrum (from Latin, of unknown origin), also known as foremilk, is the first form of milk produced by the mammary glands of humans and other mammals immediately following delivery of the newborn. Animal colostrum may be called beestings, the traditional word from Old English dialects. Most species will begin to generate colostrum just prior to giving birth. Colostrum contains antibodies to protect the newborn against disease and infection, and immune and growth factors and other bioactives. The bioactives found in colostrum are beneficial for a newborn's health, growth and vitality. Colostrum strengthens a baby's immune system.
At birth, the environment of the newborn mammal shifts from the sterile conditions of the mother's uterus, with a constant nutrient supply via the placenta, to the microbe-rich environment outside, with irregular oral intake of complex milk nutrients through the gastrointestinal tract. This transition puts high demands on the gastrointestinal tract of the neonate, as the gut plays an important part in both the digestive system and the immune system. Colostrum contributes significantly to initial immunological defense as well as to the growth, development, and maturation of the neonate's gastrointestinal tract by providing key nutrients and bioactive factors. Bovine colostrum powder is rich in protein and low in sugar and fat. Bovine colostrum can also be used for nonorganic failure to thrive in children and acute non-steroidal anti-inflammatory drug-induced increase in intestinal permeability in males and can boost a neonate's immunity.