In one aspect of the invention features nursing bottle. The nursing bottle includes a container for holding a liquid and having a rim defining an open end and a nipple assembly secured to the container at the open end. The nipple assembly includes a flexible nipple extending away from the container and defining an interior nipple volume, a vent bulb disposed within the interior nipple volume and defining an interior bulb volume, a tube extending into the container to a distal end disposed in a closed end of the container, and a vent manifold. The vent manifold defines a first aperture providing fluid communication between the container and the interior nipple volume, a second aperture providing fluid communication between the tube and the interior bulb volume, and a vent conduit providing fluid communication between the interior bulb volume and atmosphere.