HEATIME™ is an innovative system to determine heat symptoms in cows. HEATIME™ not only detects motion activity in a narrow sense but also detects overall motion activity, including general nervous movement or straddling. This system offers a variety of unique and innovating features. Easy installation (plug & play), it does not require any calibrations. "optic-infrared" data transmission; measurement of the "activity index" which accurately respects the overall animals behavior; it operates separately from other herd managing systems and allows data transmission to a computer.