Figure 2.

Determining cage dirtiness using the Bedding Status Index (BSI). The BSI is measured in units of electrical capacitance. The initial value is an arbitrary starting point established when the board is calibrated, meaning that this number has no significance. As the bedding becomes saturated with fluid over time, this value steadily decreases until it reaches the Drop_board value that triggers an alert for cage change. When the cage is changed, the capacitance returns to the initial value.