Quoting White Chocolate Milk:" He gets a sippy of milk when he eats breakfast lunch and dinner and he gets a bottle to go to sleep which ... [snip!] ... milk but it has to be going some where lol. And I seriously doubt DS is able to drink that much and still eat the way he does."
A sippy is probably about 5 oz, so with him getting one at each meal thats about 15 and then the bottle at night time you would have to add.
With night time bottles, try water instead, and/or reduce the amount and continually reduce it so you break the habit.