Why mother’s milk is considered very essential for the new- born infant?

Why breast-feeding during the initial period of infant growth is recommended by doctors or important for bringing up a healthy baby ? or why mother’s milk is considered very essential for the new- born infant?

The mammary glands of the female undergo differentiation during pregnancy and starts producing milk towards the end of pregnancy by the process called lactation. This helps the mother in feeding the new- born. The milk produced during the initial few days of lactation is called colostrum which contains (The yellowish fluid colostrum secreted by mother during the initial days of lactation has abundant antibodies (IgA) to protect the infant. The foetus also receives some antibodies from their mother, through the placenta during pregnancy. ) several antibodies absolutely essential to develop resistance for the new-born babies.