A system and method of determining a physiological state of a ruminant animal by monitoring the pH and temperature of the animal's stomach. A battery-less, single unit sensor and transmitter is placed within the rumen or reticulum of the animal. pH and temperature measurements are taken and transmitted...http://www.google.fr/patents/US20040133131?utm_source=gb-gplus-shareBrevet US20040133131 - In vivo ruminant health sensor
