Application of RFID technology using passive HF transponders for the individual identification of weaned piglets at the feed trough

The study examined simultaneous individual animal identification of newly weaned piglets based on radio frequency identification (RFID) using passive high frequency (HF) transponders focusing on identification rate and identification accuracy. The antenna for simultaneous individual animal identification was integrated into the round trough of the feeder and connected to a conventional high frequency long range reader. HF transponders were attached to the eartags of the piglets. An anti-collision system was used in order to facilitate simultaneous registration of animals which were within reading range of the antenna at the same time. Anti-collision systems allow multiple access handling and prevent the collision of transponder data within the reading range of a RFID reader, which would render data unreadable. In order to determine the identification rate of this innovative system, trough visits of selected focal animals registered by the simultaneous individual animal identification were verified using video observation. The anti-collision system of simultaneous individual animal identification was validated through group observations.The identification rate of 97.3% in simultaneous individual animal identification was very high. 33.3% of the trough visits were thereby registered simultaneously. 64% of the trough visits were registered with a short time delay. Average time delay of simultaneous individual animal identification did not exceed 3.00 s. The simultaneous individual animal identification sensed the beginning of a trough visit 0.28 ± 6.08 s earlier than the observer. The simultaneous individual animal identification registered piglets leaving the trough on average 2.77 ± 7.11 s earlier than the observer. Frequenting the trough had a significant influence on the functionality of the simultaneous individual animal identification. The number of animals registered by the simultaneous individual animal identification differed on average by 0.19 ± 0.04 piglets from the result of the observer if one single piglet was within the range of the antenna. If more than five animals were within the range of the antenna, a deviation of 1.04 ± 0.19 animals was observed (P < 0.0001).The demonstrated system in principle represents a good possibility to simultaneously identify piglets online at the round trough of a feeder.