After 6 months or so, certainly past 1yo, kids who are otherwise growing well don't physically need those middle-of-the-night bottles - they're what the behaviorists call "trained night wakers". It's up to you how aggressively you want to wean this, but here's a good tip.
Take the bottle that hurts you the most (4am, anyone?), and water it down over several nights, until you're offering a bottle of just water. That often helps the child give up that particular habitual wakeup. Remember to be brief and boring about it, as well.