Colostrum is a milk-like substance that comes from the breasts of  mammals for the first few days following birth. It is sometimes referred to as first milk, as it comes before true milk appears and is high in fat for energy, proteins, carbohydrates, vitamins and minerals. However, it is the protein molecules that hold a special function. Some of these proteins are antibodies that fight disease-causing agents such as bacteria and viruses, which a newborn is exposed to as soon as it enters the environment outside of its mother. These provide the newborn with passive immunity; basically kick-starting the immune system development.
Antibody levels in colostrum can be 100 times higher than levels in regular milk. Anti-microbial factors are also contained within colostrum, adding to the protective nature of this substance. Another important component of colostrum is the range of growth factors; these stimulate the development of the gut. Colostrum also contains proline rich peptides (PRPs) which are other special protein molecules. PRPs are the ‘messenger’ molecules that modulate the immune system, acting like a kind of volume switch, turning up when needed and turning down when things are quieter.