This GPS-Tracking Ear Tag System, which includes tags and app, allows one to remotely monitor livestock-not only as to their location, but also on their safety, health, and performance-related conditions/situations. The tags' sensors continually monitor and (via the app) report to one's cellular device the animal's movement and (1) instantly send out-of-fence, illness-suspected, and calving alerts and (2) detect and daily report bull-mounting and cow estrus occurrences. The tags are solar powered and Bluetooth enabled. (Note. No base station is required, but cellular connectivity requires a $50 annual subscription fee per tag.)