Final answer:
The importance of colostrum for a newborn lies in its high content of immunoglobulins, providing passive immunity that bolsters the newborn's immune system during the critical first days postpartum.
Step-by-step explanation:
A valid defense of breastfeeding, particularly the significance of colostrum during early breastfeeding, centers on its role in bolstering the newborn's immune system. While it is true that a baby only receives a tiny amount of colostrum, this substance is incredibly nutrient-dense and contains high levels of immunoglobulins that are crucial for protecting the newborn as they adjust to a nonsterile environment. Specifically, colostrum is secreted during the first 48-72 hours postpartum and, despite its small volume, is perfectly suited to the newborn's developmental needs. It helps the baby's digestive system expel meconium and clear bilirubin, thereby increasing the baby's immune defenses through what is known as passive immunity.