A tamper proof ear tag system for preventing reattachment of an ear tag to a second animal that was removed from a first animal. The tamper proof ear tag system includes an attachment member that is permanently inserted into a receiving member wherein the receiving member is attached to an ear tag. The...http://www.google.fr/patents/US20030121188?utm_source=gb-gplus-shareBrevet US20030121188 - Tamper proof ear tag system
