Validation of a High Frequency Radio Frequency Identification (HF RFID) system for registering feeding patterns of growing-finishing pigs

•A HF RFID system was validated for registering feeding pigs.•The system was used in simulated commercial farm conditions.•Specificity for individual pigs with one or two tags was always above 85%.•Sensitivity varied for individual pigs, tags and different time windows used.•A sensitivity of 88.58% and a specificity of 98.34% can be reached.

Automated monitoring of the feeding patterns of growing-finishing pigs would allow detecting problems with individual pigs or groups of pigs and thus improving health, welfare and productivity of the farm. In this paper a High Frequency Radio Frequency Identification (HF RFID) system was validated for its suitability to register individual pigs’ feeding patterns at a round trough in a group-housing context. High Frequency RFID antennas were installed above the troughs of a commercially available type of round feeder to identify feeding pigs fitted with one or two passive RFID tags on their ears. A multiplexer was used to connect multiple antennas to a single reader. During 11.5 h, video observations of 20 focal pigs (equipped with two tags) at an age of 16 weeks were performed to validate the system. A large variation in feeding patterns of the 20 focal pigs was found. Correlation between the number of registrations per pig and the feeding duration on video was low (R2 = 0.53) mainly due to four pigs with specific feeding behaviour (with the four pigs excluded: R2 = 0.88). The RFID registrations of the 20 focal pigs – with irregular time gaps between them – were compared with instantaneous video samples using several time window sizes around the video sample. The specificity for individual pigs with one or two tags was always above 85%, but sensitivity varied for individual pigs, tags and with different time windows used. A quantitative comparison between the use of one or two tags per pig was made based on a receiver operating characteristic (ROC) curve. For two tags per pig a sensitivity of 88.58% and a specificity of 98.34% can be reached with a time window size of 9 s. For one tag per pig, sensitivity is only above 85% at a time window of size 31 s. Of the total number of RFID registrations 77.11% occurred during feeding visits, and 92.23% occurred during or within 10 s of feeding visits on video. This system showed good potential for measuring feeding patterns of growing-finishing pigs in commercial pig houses, for research purposes, or to detect potential problems with pigs by signalling changes in the registered feeding patterns.