With diseases such as Foot and Mouth, TB, and of course Mad Cow still presenting a danger to cattle, it's of the utmost importance that farmers monitor the health of their animals, and immediately proceed to isolate any that might be showing symptoms. If you have a herd of over 500 cows, however, keeping track of individuals can be rather tricky. That's why scientists at England's Newcastle University have developed electronic ears tags, that they're trying out on a herd of test cattle.

Each ear tag is equipped with an RFID (radio frequency identification) chip, that transmits a short-range 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.

If a cow isn't eating enough - which could indicate that it isn't feeling well - the system notifies the farmer, identifying which cow should be looked at.

The cattle also have pedometers attached to their ankles, which measure how much time the animals spend being active versus lying down - another indicator of their health.

"Modern farming systems have minimized the contact between the animal and its keeper," said project co-leader Prof. Ilias Kyriazakis, "so we need to constantly look for ways to re-address the balance."

The Newcastle research was recently published in the Annual Proceedings of the British Society for Animal Science Conference 2011.