A vent plug for a milking liner has a shielded inlet that reduces the likelihood that it will become clogged with debris from the floor of the milking parlor. In one embodiment, the vent plug has a plurality of redundant inlets that allow the vent plug to function if one of the inlets becomes clogged. In another embodiment, the inner flange of the body of the vent plug is at least twice the thickness of the body tube to help secure the vent plug in the milking liner.