Correlations between ovarian follicular blood flow and superovulatory responses in ewes

The primary goal of this study was to employ ultrasonography to examine the ovariesof ewes undergoing superovulatory treatment for correlations between antral follicularblood flow and ovarian responses/embryo yields. Five Santa Inês ewes were subjected toa short- (Days 0–6, Group 1) and five to a long-term progesterone-based protocol (Days0–12, Group 2) to synchronize estrus and ovulations after the superovulatory treatment. Porcine FSH (pFSH, 200 mg) was administered in 8 decreasing doses over 4 days, start-ing on Days 4 and 10 in Groups 1 and 2, respectively. After CIDR removal, all ewes werebred by a ram and embryos were recovered surgically 7 days later. Transrectal ovarianultrasonography was performed the day before and on all 4 days of the superovulatorytreatment. Both an arbitrary-scale [(0) non-detectable; (1) small; (2) moderate; (3) intenseblood flow] and quantitative analysis of the blood flow area were used to assess the fol-licular blood flow in color Doppler images. There were no significant correlations betweenthe arbitrary blood flow scores and superovulatory responses in the ewes of the presentstudy. However, there was a positive correlation between the quantitative estimates offollicular blood flow on the final day of the superovulatory treatment, and the number (DA: r = 0.68, P < 0.05; DA/TA × 100%: r = 0.85, P < 0.05) and percentage (DA: r = 0.65, P < 0.05;DA/TA × 100%: r = 0.91, P < 0.001) of unfertilized eggs (DA: Doppler area, TA: total area ofthe largest ovarian cross section). This experiment presents a commercially practical toolfor predicting superovulatory outcomes in ewes and evidence for the existence of follicu-lar blood flow threshold that may impinge negatively on oocyte quality when surpassedduring hormonal ovarian superstimulation.