Relationship between sheep attendance, time spent and weather variables at RFID-equipped lick and loose-lick feeders

Our study investigated the relationship between sheep attendance and time spent at lick and loose-lick feeders in grazing environments. These feeders were equipped with radio frequency identification (RFID) systems specifically designed for collecting the data simultaneously from multiple animals in a group feeding situation using either low-frequency (LF) or ultra-high frequency (UHF) readers. Two trials on two separate sites were conducted: site a) lick feeders offering a pelleted ration (Wagga Wagga, NSW, Australia), or site b) loose-lick feeders offering coarse salt (Cowra, NSW, Australia). Each site had two replicates (45 lambs per paddock) for each RFID system. We observed a strong relationship between daily visit frequency and daily time spent at the feeder; the fitted models explained more variation for pellets (R² = 0.96 for LF; 0.98 for UHF) than for salt (R² = 0.82 for LF; 0.80 for UHF). At the individual level, we observed that lambs showed moderate to high associations between attendance and time spent at the feeder (R² = 0.66 to 0.93). However, frequent visits by some lambs did not reflect longer feeding time. We used partial least squares analysis to identify variables associated with visitation based on the LF dataset. For salt, visitation was positively associated with humidity and negatively associated with delta temperature and vapour pressure deficit. For pellets, air temperature showed the strongest negative association with visitation, whereas humidity and average daily gain (ADG) were positively associated. Attendance and time spent at the feeder provide practical individual-level monitoring indicators, which could aid efforts to improve the uniformity of supplement delivery.