My baby is 4 months old . He was on mixed breast feed and formula feed . Now am expressing breast milk and keeping it in feeding bottle . Just before his feed time I express . But whenever he is hungry he is not eating the breast milk , rather he is adequately taking formula feed . Amount of breast milk consumed is also less . What to do . I want to give him breast feeding either directly or through expressed milk . Please suggest . May be it due to milk becoming cold which he don’t like . How to warm the bottle containing the breast milk . Please suggest