My DD2 just turned 3 months this week. She feeds 7 times in a 24 hour period and takes about 4.5 oz each time, so that is about 31.5 oz. Some days she seems to want several 5 oz bottles, other days if I make bottles that size, she leaves an ounce or more. As Lolly said, appetite is highly variable among babies, and even among the same LO from day to day.