The present inventions relate to apparatus and systems for feeding livestock, particularly to nipple-actuated feeding stations which include a nipple insert assembly having an internal valve system actuable by a nipple and insertable into an insert assembly having a normally-closed internal valve system and connectible to a pressurized feed line. Inserting the nipple assembly into the insert assembly opens the insert assembly valve system and subsequent nipple actuation discharges fluid from the pressurized feed line. The nipple assembly may be removed from the insert assembly without depressurizing the feed line or manipulating other process conditions. A plurality of insert assembly and nipple assembly pairings may be positioned throughout one or more pressurized feed lines to form a feeding system, and the flow rates of each individual feeding station may be manually or automatically controlled.