It is better to stick to one medium formula feed only once if you face problem. Mostly boys have a higher appetite compared to girls. As Sonali mentioned it could be nipple confusion. Slowly you can introduce bowl and spoon which is easier to sterilise too.

When a baby has been given the bottle it causes nipple confusion as feeding from a bottle is very different as compared to feeding from the breast. It is also much easier and hence baby prefers the bottle. If you would want to have the baby latch directly it is very importation first completely stop the use of the bottle for atleast seven days. Even if it means fussing a crying. To answer your second question do not give outside milk toned double toned full cream skimmed to a baby under one year of age.