Each rfid animal ear tag is equipped with an RFID (radio frequency identification) chip, that transmits a signal. Antennas mounted on the feeding troughs will pick up that signal when the cow comes to feed, with a computer keeping track of the amount of time that elapses until the signal is lost when the cow leaves. In this way, the system can keep track of which cows are eating regularly, and that they're getting enough to eat when they do.