Fig. 1

Sensor position, orientation and orientation changes when lying and standing. a Orientation and location of the neck collar mounted sensor on the neck of the cow. b Schematic figure of the coordinate frame of the sensor with X forwards, Y right and Z down according to the illustration. When a cow is wearing a neck collar with attached sensor, a change in the acceleration in the x-axis corresponds to a sidewise movement to the left or to the right. A change in the acceleration in the y-axis measures the forward and backward movements while changes in the acceleration in the z-axis measure the sidewise rotation of the neck. c Example of the orientation of the sensor when a cow is observed standing. The component in the y-axis of the gravitation acceleration varies according to \( \overrightarrow{{\mathit{\mathsf{g}}}_{\mathit{\mathsf{y}}}}=\mathit{\mathsf{g}}\ast \mathsf{cos}\ \left(\mathsf{180}-\beta \right) \) where β is the angle in degrees of the sensor relative to the horizontal. d Example of the orientation of the sensor when a cow is observed lying. The component \( \overrightarrow{{\mathit{\mathsf{g}}}_{\mathit{\mathsf{y}}}} \) will be different from standing as the angle α for lying is bigger than β