Monitoring variability in sheep time spent at commercial loose-lick feeders using radio frequency identification

We used Low-frequency (LF) Radio Frequency Identification (RFID) technology to assess individual lambs' time spent at commercial loose-lick feeders as a proxy for individual supplement attendance variability, in a context where supplement intake was not directly measured. Ninety Merino ewe lambs (42.7 ± 5.2 kg) grazing lucerne-dominant pasture were supplemented with coarse salt for 28 days. Marked individual and temporal variation in time spent at the feeder was observed throughout the trial (P < 0.05). We observed significant variability in feeder time, with some lambs spending, on average, under 1 minute, and others over 5 minutes per day. Approximately 70% of the lambs spent a minimum of 0.6 minutes per day at the feeder. Also, temporal variability was evident, with certain lambs increasing their attendance toward the end of the study, while others showed consistently low attendance. Using clustering analysis, we identified that 29% of lambs spent more time at the feeders (4.1 ± 0.278 min/an/day), exhibiting longer visit durations and higher visit frequency, compared to 18% of lambs with the lowest time spent (1.62 ± 0.094 min/an/day). Our findings emphasise the difficulty of ensuring consistent supplement consumption in extensive grazing systems. Fitting LF RFID to commercially available loose-lick feeders could improve understanding of factors influencing supplement delivery, such as mob size, feeders per mob and grazing environment.