Measuring lamb activity during lactation by actigraphy.

Twenty-two lambs were used to determine their locomotor activity during lactation, and its circadian rhythm, based on data collected by actigraphy; the relationships among lambs were also measured calculating their proximity and distance. Lambs were fitted with Bluetooth-enabled (BT) accelerometers during weeks 1 and 4 of age, and data were downloaded as activity counts at 1-min intervals (Vector Magnitude, VM). Sensors were programmed as receivers and as beacons of the BT signal to calculate proximity (min/h) and distance (m) to another lamb.