Abstract: An estrus detection system using a transponder mounted to an animal and including a motion sensor. The motion sensor produces a series of pulses as a function of movement. A counting circuit is energized by the sensor. A storage circuit retains the count together with an identification code unique to the animal. The transponder is interrogated to receive data and such is processed to determine estrus.

Abstract: A system for passively identifying remote objects such as livestock is disclosed. A power transmitter transmits a plurality of radio frequency burst signals at a given frequency, and a uniquely coded transponder associated with the object to be identified produces a plurality of coded identification signals in response to the burst signals from the transmitter. The coded identification signals are read by a receiver to identify the object. The transmitter and receiver are time division multiplexed for alternate operation. Accordingly, when an object is to be identified, the transmitter is switched on to transmit the burst signals, thereby activating the transponder to produce the coded identification signals. The transmitter is then switched off and the receiver switched on to receive the identification signals for identifying the object.

Abstract: This invention is drawn to a bovine vaginal probe capable of measuring electrical resistance in a bovine vaginal tract with sufficient accuracy to allow detection of changes in electrical resistance indicative of estrus.The electrodes of the probe are generally axially aligned on the surface of a generally cylindrical support. In the essentially axially parallel electrode configuration, in order to obtain the desired sensitivity where one set of electrodes are employed, the electrodes should be separated from each other by at least 45.degree. and preferably at least about 90.degree.. One preferred essentially axially parallel configuration employs two sets of electrodes, each separated by approximately 90.degree. so that two sets of resistance figures, ventral and dorsal can be obtained.