A bovine estrus detection device includes a generally rectangular base having sides and ends, the base having a predetermined length and a predetermined width, and the width being less than the length, the base having a first side and. a second side. The first side of the base has a central region having a first color and end regions having a second color. The second color is different from the first color. An adhesive is disposed on the second side of the base for coupling the base to a female cow or heifer. A removable coating is disposed over the first side of the base. The removable coating is exposed for contact by male or female cows mounting the female cow or heifer to which the device is attached. The coating is adapted to being removed by mounting male or female cows, whereby the first and second colors become visible. Exposure of the first color in the central region is an. accurate predictor of activation and estrus.