Practical test and evaluation of optimized UHF ear tags for behavior monitoring of fattening pigs

Abstract

Abstract. Low frequency radio frequency identification (LF-RFID) systems have been established as a standard for animal identification. Ultra-high frequency (UHF-) RFID systems could provide other advanced applications such as automated activity measurement and real-time localization of animals. However, strong influence of reflections and absorption lead to signal attenuation, which poses major challenges for UHF systems. Especially ear tissue causes strong absorption of the electromagnetic waves, changes in the resonance frequency of UHF transponders and, thus, impairs reading performance. In a current research project, UHF transponder ear tags, readers and antennas for pig farming are being developed further. The objective of this study is to test a series of small UHF ear tags, which were designed especially for use in growing-finishing pigs. Five different types of UHF transponder ear tags were tested in a test setup for behavior monitoring. For this purpose, a playing device with a straw container and a wooden beam was equipped with a RFID antenna to detect the pigs‘ visits. The RFID data was compared to reference data from video observation to evaluate the readability in a defined area around the playing device. A binary classification was used to calculate sensitivity, specificity, precision and accuracy of the visit detection to the split second. Three of five transponder types achieved a satisfying performance. Based on these results, suitable types will be selected for a further reduction of size for piglet ear tags. This field trial showed that a reduction of transponder antenna size without loss of performance is possible.