Bovine follicular and luteal bloodflow during the estrus cycle. Clinical evalutation of the ultrasound Doppler technology.

Abstract

Color Doppler technique in cattle reproduction is a useful tool to visualize physiological and pathological processes of the reproductive system. The objective of this study is to make an evaluation of the blood flow during follicular and corpus luteum development in the estrus cycle and find a correlation between the blood flow, progesterone levels and size during the cycle. Six Holstein-Friesian cows are synchronized and examined sonographic during the estrus cycle and progesterone levels are measured every other day. Ovulation is induced using prostaglandins at day 14. The maximal cross-sectional size of the follicles and corpora lutea are measured sonographic, the blood flow to follicles and corpora lutea are examined using Color Doppler images. A correlation of r=.351 between follicle growth and blood flow for follicles larger than 10 mm is found. The blood flow and progesterone levels are correlated during growth, static and regression phase, where progesterone and luteal size are only correlated during growth and regression phase. Over the complete cycle a correlation of r=.788 is found between blood flow and progesterone levels (r=.766 for progesterone and luteal size). This indicates that blood flow can give a reliable estimation of the functionality of the corpus luteum. It is concluded that the ovarian blood flow is a reliable research method, which gives useful additional information in fertility counseling.