a valve mechanism comprising:

a valve body having a chamber, at least one inlet, and an outlet for fluid communication with the inlet through the chamber;

a valve stem in the valve body chamber rotatable about an axis of rotation between at least two positions including an open position permitting fluid flow from said at least one inlet of the valve body to said outlet of the valve body and a closed position preventing such fluid flow, said valve stem having a front portion comprising a fluid pathway in fluid communication with said at least one inlet and said outlet when in said open position and not in fluid communication with said at least one inlet and said outlet when in said closed position and a back portion; and

an open-top channel in the back portion of the valve stem for receiving a rotatable shaft on said flow control apparatus, said open-top channel having an open top along the length of the channel intersecting said axis of rotation;

said channel being aligned with said outlet when the valve stem is in said closed position to permit engagement of the valve mechanism to the flow control apparatus and misaligned with said outlet when the valve stem is in said open position to prevent disengagement of the valve mechanism from the flow control apparatus;

inlet tubing attached to the at least one inlet of the valve body;

outlet tubing attached to the outlet of the valve body; and

a mounting member on said outlet tubing adapted for engagement with said flow control apparatus;

said mounting member having first and second portions, and one or more identification members selectively positioned on one or both of said first and second portions of the mounting member in a configuration corresponding to a particular functional configuration of said administrative feeding set.