Technical note: a pressure-sensitive sensor for measuring the characteristics of standing mounts of cattle

A pressure-sensitive sensor that reacts to pressure by changing its electrical resistance was used to measure the characteristics of standing mounts of estrous cattle. While an estrous heifer fitted with a sensor on the rump was standing when mounted by a bull (i.e., during a standing mount), the sensor reacted to the addition and removal of pressure against it by the bull. The times of electric contact signals produced by these pressure changes were recorded to pinpoint the time of the mounted response and the duration of the mount. To detect the characteristics of standing mounts accurately, three types of sensors with different sensitivities and various positions on the rump of heifers were examined. When 13.5-cm sensors that operated with a pressure of 1,000 g/cm2 were fitted on the line combining the highest points of the left and right hip bones toward the tail, or 6.5 cm behind this position, on the rump of heifers (200 to 225 kg), mounts by vasectomized bulls (278 to 556 kg) were accurately recorded with the sensors more than 85% of the time. However, the correlation between the observed and automatically recorded lengths of mounting varied with combinations of the mounted and mounting animals or with locations of the sensor (r = .19 to .86). The pressure-sensitive sensor proved to be a promising device for continuously measuring the characteristics of standing mounts, especially the exact time at which a mount occurs.