[en] Real-time ultrasonography is an essential diagnostic tool in the bovine reproductive tract examination. It is a simple, reliably and non invasive imaging technique that provides information beyond transrectal palpation of the ovarian and the non pregnant as well as the pregnant uterus. The ultrasound examination admits of estimation the normal structures, anomalies and homodynamic changes in reproductive organs and the embryo and fetus development. To obtain a good quality and detailed images of the reproductive tract is preferred a 5.0 to 7.5 MHz probes. This paper has focused the principles of ultrasound imaging use in a cow’s theriogenology.