Might as well! Maybe just fill it like 1/4 of the way in case he doesn't drink it right away. That way you won't have to throw out a bunch of milk while he figures out that's how he will be getting his milk from now on
@ciraclesmiracle, yes! He does well with it but I'm not quite sure how to introduce milk in his sippy. The flow is too fast so I don't think he could just sit and drink all his milk like he would from a bottle. He likes to sip on water throughout the day, and obviously he can't do that with milk. Not sure how to do it.