The present invention 10 provides a system and method of monitoring and tracking a plurality of physical variables from a remote location. The invention 10 utilizes a plurality of radio frequency identification transponders 20 each coupled with a sensor for measuring physical data. The transponders 20 are powered by a radio frequency reader/interrogator 60 that provides radio frequency excitation to the transponders 20 and receives and demodulates back-scattered signals therefrom. The invention 10 is particularly advantageous in monitoring temperature in cattle herds as an aid to early diagnosis of bovine respiratory disease.