Colostrum is a special substance secreted by the mammary glands of all mammals near the time of birthing. It was designed by nature to promote health, strength, and vitality in the newborn. If you breastfed colostrum was your first meal. Colostrum contains a multitude of healthful components that work for adults as well as the newborn. Colostrum for human use is harvested from dairy cattle, after the calves have been given an amount adequate for their needs.