I wouldn't do that. Just because once you heat up milk it's not good to reheat it. Also once the baby drinks from a bottle they say not too keep it too long due to the increase risk of bacteria growth.
Actually. Sorry I take my last comment back. Apparently I'm completely wrong. I never re-reheated breast milk but its actually alright to do. Here's a little something I just read about it. Hope it helps
Breast milk is super-resistant to bacteria. It's way more durable than formula, which means that you can leave it out a while and refrigerate it and the baby can still drink it. Look up La Leche League for information.