Innovative monitoring of supplement intake in grazing beef cattle using bluetooth ear tags

Forage-based beef cattle production systems commonly provide supplements to optimise production. However, current methods assess supplement intake at the herd level, failing to capture individual variation. This study aimed to 1) evaluate the use of Bluetooth ear tags to estimate individual supplement intake by tracking time spent at the feeder; and 2) assess the performance of Bluetooth ear tags in predicting individual time spent at the feeder. Fourteen Droughtmaster heifers (268 ± 32.7 kg) were fitted with Bluetooth ear tags, allocated to a 10-ha paddock with low-quality pasture, and provided two protein supplements (low intake and high intake) over 12 weeks. The time spent at the feeder was recorded through visual observation, supported by camera footage, and Bluetooth receiver, which logged the presence and received signal strength indicator (RSSI) values from the ear tags. RSSI values ≥ -50 dBm were found to accurately estimate time spent at the feeder when compared with video data (R 2 adj = 0.47, P < 0.001). Incorporating the acceleration index mean further improved the predictive power of the model (R 2 adj = 0.70, P < 0.001). Significant individual variation in supplement intake was observed, with a coefficient of variation ranging from 26 % in period 1–14 % in period 2. Overall, Bluetooth ear tags demonstrated potential for predicting time spent at the feeder, a key factor in estimating individual supplement intake. Bluetooth ear tags could be valuable for developing phenotyping metrics, selecting animals with efficient responses to supplements, and improving productivity and sustainability in beef cattle production.