ABSTRACT
The use of different ultrasound modalities (color, power and pulsed Doppler) in clinical research has enhanced knowledge of reproductive pathophysiology in equine, in addition to improving the clinical diagnosis of reproductive disorders in both the stallion and the mare. In the stallion, color Doppler ultrasound has improved the diagnostic potential of conventional ultrasound, improving the differential diagnosis of pathologies such as testicular torsion (decrease or absence of blood flow in the cord) and orchitis (increased blood flow in the cord). The function of the testicle is highly dependent on the blood flow it receives; therefore, any vascular alterations can affect both the quality and production of sperm. In recent years there have been a greater number of studies in which Doppler ultrasound is used as a tool in the diagnosis of testicular dysfunction and in the monitoring of medical and surgical treatments. In the mare, ultrasound technology has allowed numerous advances in basic research regarding the vascular hemodynamics of the ovary and uterus. Moreover, it has become an indispensable tool in reproductive practice. Among the clinical applications of this technique in mares are the evaluation of CL (corpus luteum) functionality, being a useful tool in the selection of recipients in embryo transfer programs or the use of power Doppler in the diagnosis of pregnancy as early as 7 days postovulation prior to flushing. Finally, the incorporation of color and pulsed Doppler ultrasound into the examination improves the diagnosis of mares with endometritis due to a pathological increase in uterine blood flow.