Applications of Doppler ultrasonography in reproductive health and physiology of small ruminants / Aplicações da ultrassonografia Doppler na fisiologia e saúde reprodutiva de pequenos ruminantes

ABSTRACT

Major applications of Doppler ultrasonography for evaluating reproductive potential of healthy sheep and goats are discussed in this mini-review. Basic principles of Doppler imaging and examination techniques used are also briefly described. In ewes and does, Doppler ultrasonography has primarily been used in reproductive research involving superovulatory treatments and fetal development. In both species, color Doppler sonography has proven to be an accurate non-invasive method of detecting luteal structures and monitoring changes in luteal status/dynamics during the interovulatory period and pregnancy. Studies in rams have documented changes in testicular blood supply during the period encompassing the onset of puberty as well as seasonal fluctuations in velocimetric indices of testicular arteries and their relationships to spermatogenesis/semen quality, testicular volumes and circulating concentrations of reproductive hormones. Quantitative correlations between high-velocity antral follicular blood flow and superovulatory yields in ewes promise to provide a reliable non-invasive method to predict superovulatory outcomes. Umbilical cord hemodynamics are a useful marker of fetal development and health status. However, the relationships among velocimetric indices of major supplying arteries and ovarian/testicular or mammary gland function are still equivocal and require additional confirmatory studies of multiple influencing factors.(AU)