A nursing bottle assembly having a container with a closed bottom end, a top end opposite said bottom end and having an opening therein for receiving liquid into an interior of the container, a neck at the top end with an inner diameter defining the size of the opening at the top end, a nipple, and a threaded collar sealing between said nipple and said neck while allowing liquid to flow from said container to said nipple, and to provide closure for the opening at the top end, wherein the improvement comprises: