What is colostrum like?

Colostrum is the general term for the milk secreted by female mammals within 2 to 3 days after giving birth. After delivery, the mother's hormone levels change and the breasts begin to secrete milk. However, there is a gradual change in the quality and quantity of lactation. Generally, the milk produced within 4 to 5 days after birth is called colostrum, the milk produced 6 to 10 days after birth is called transitional milk, the milk produced 11 days to 9 months after birth is called mature milk, and the milk after 10 months is called late milk. This change in the quality and quantity of breast milk is just what adapts to the digestion, absorption and physical needs of the newborn. Colostrum, in addition to fat lymphocytes ingested by phagocytosis, also contains mammary cells and cell fragments and nuclei from the ducts. Because colostrum contains a lot of salts such as calcium phosphate and calcium chloride, it has a mild laxative effect. Colostrum also has a higher calorie content than mature milk. After giving birth, when the effect of the placenta's follicle hormone disappears, the effect of prolactin begins, and the mother begins to secrete milk.

Within 1 to 2 days after delivery, the composition of colostrum is close to that of the mother's plasma. After that, the composition of colostrum changes significantly almost every day. The content of protein and inorganic matter gradually decreases, the lactose content increases day by day, and the proportion of casein increases day by day. After 6 to 15 days, it turns into normal milk. Colostrum is not suitable for processing into daily drinking milk due to its poor sensory properties, slightly salty taste, and poor thermal stability. There are now many colostrum products on the market, and the main active substances retained are the immunoglobulins in the colostrum.