Which type of milk is produced first after childbirth and is rich in antibodies?

The correct choice is colostrum, which is the milk produced in the first few days after childbirth. Colostrum is particularly significant because it is rich in antibodies and essential nutrients that support the newborn’s immune system. This thick, yellowish fluid is packed with essential proteins, fats, vitamins, and minerals, making it a vital first food that helps establish a healthy gut flora in infants. The antibodies found in colostrum provide critical protection against infections and diseases during the early days when the baby's immune system is still developing.

In contrast, milk letdown refers to the reflex that allows milk to be released from the breasts during breastfeeding, rather than being a type of milk itself. Mature milk, which appears a few weeks postpartum, has a different composition than colostrum, being higher in fat and lower in protein and antibodies. Sour milk typically refers to milk that has fermented or spoiled, which is not suitable for feeding to infants. Thus, colostrum stands out as the specialized milk produced immediately after birth, distinguishing its unique benefits for newborns.