Doppler Ultrasound in the Reproduction of Mares

Doppler ultrasonographic (US) is a method that provides real-time information on vascular architecture and hemodynamic aspects of blood vessels. It can determine the presence, direction, and speed of blood flow, being subdivided into the categories of color Doppler (color flow and power flow) and pulsed Doppler. The objective of this chapter was to compile data from several studies addressing the use of US Doppler correlated with pathophysiological phenomena of equine reproduction. Initially we decided to describe the technique, advantages, and disadvantages of each Doppler mode. Then the applicability of US Doppler in mares related to equine reproduction. Thus, within this chapter, you will find the form of use and descriptions of studies carried out on vascular perfusion of the follicular dynamics, the corpus luteum, the uterine segments, which we have divided into post-insemination evaluation, endometritis diagnosis and pregnancy diagnosis. So, we hope that this chapter will expand the knowledge about US Doppler and increase the number of veterinarians who will introduce the technique into their practical routine.

Correlations of corpus luteum blood flow with fertility and progesterone in embryo recipient mares

The aim of this study was to evaluate the correlation between the corpus luteum vascularization with the concentration of progesterone and the fertility of embryo recipient mares. Mangalarga Marchador mares (n = 33) were distributed into groups according to the days (D) after ovulation, as follows: D3 (n = 8), D4 (n = 8), D5 (n = 9), and D6 (n = 8). The evaluations of the corpus luteum, endometrium, and blood collection to quantify the progesterone concentration were carried out on D3, D4, D5, and D6. Among the parameters evaluated, only progesterone concentration on D6 differed from the other groups (P <0.05). A positive correlation (P <0.05) between the diameter and the area of the corpus luteum, and the objective and subjective methods of the corpus luteum vascular perfusion, was identified. Likewise, a positive correlation (P <0.05) was observed between the objective and subjective methods of the vascular perfusion in the corpus luteum and the progesterone concentration. The pregnancy rate obtained in this study (54.54%) was not affected (P> 0.05) by the day of embryo transfer, whose percentages were 37.50% (3/8) on D3, 50% (4/8) on D4, 66.70% (6/9) on D5, and 62.50% (5/8) on D6. It was estimated that with each increase on the day of embryo transfer, the pregnancy rate increases. The results allow to conclude that the corpus luteum vascularization in mares, evaluated by Doppler ultrasound, correlates with progesterone concentration and the embryo transfer day.