An ultrasonic sounding apparatus is described for measuring backfat and determining pregnancy in animals, having a plurality of self-test features to ensure integrity of the measurements. In the preferred embodiment, a hand-held ultrasonic device is described for detecting increased amounts of amniotic fluid in an animal's uterus for an indication of pregnancy. Every two and one half seconds the hand-held ultrasonic device emits a small tone indicating that the transducer is in correct contact with the body of the animal. The generation of this skin contact tone is performed using the same ultrasonic circuitry that is used to detect the amniotic fluid, thereby providing the dual function of circuit self-test and skin contact test. In addition, the device includes a power-up confidence test to test the components of the circuit and indicate by an audible tone that everything is working properly. This power-up confidence test also uses the same ultrasonic circuitry that performs the detection of amniotic fluid. Included in this invention is a battery check that is also performed on power-up.