Is it the milk you are wanting to stop or the fact that she has her milk in a bottle? I am assuming it is the bottle? Reason I ask as you could find that it is the milk she associates with waking and sleeping and not what she has it in ITMS? My DS who is just a few weeks older than your DD has 3 "milks" a day in the morning, after lunch before his nap and at night before he goes to bed. He has this in what ever I grab - sippy cup or straw cup and its definitely the milk that he wants rather than what he drinks it out of so like Starangelk said you could change to sippy cup and she mightn't even notice.

Either way IMO its not a problem how she drinks it. Don't know if she is using a open cup yet but you could introduce that for water during the day as well as her sippy cup.

HTH