Plasma steroid hormone concentrations and blood flow of the ovarian structures of the female dromedary (Camelus dromedarius) during growth, dominance, spontaneous ovulation, luteinization and regression of the follicular wave

Abstract

The objectives of this study were to investigate the ovarian follicular waves and their corresponding hormonal changes in she-camels and to elucidate blood perfusion of the ovarian structures. Three reproductively sound, non-pregnant female camels were examined daily using B-mode and color Doppler to detect changes in their ovarian structures and blood vasculature for 22 follicular waves. Blood area (BA) and percentage (BA%) were determined for the ovarian structures. Three phases of follicular development, those of growth, maturation, and regression, were observed during each follicular wave. Deviation occurred on Day 6.1±1.08. Estradiol increased from basal levels of 27.4±0.4pg/ml to peak concentrations of 134.4±47.5pg/ml as the follicle reached a diameter of 13.2mm. Peripheral progesterone concentrations remained low (<0.4ng/ml) throughout the follicular waves. The blood flow to the dominant follicles increased gradually with follicular growth. The BA and BA% reached the maximum values of 18.4±11.6mm2 and 6.04±2.03%, respectively, when the diameter of the dominant follicle was 17.5±3.4mm. The blood flow to the corpus luteum rose markedly after ovulation to reach a maximum BA% and BA at Days 5 and 7, respectively, post ovulation. In conclusion, the follicular wave pattern in dromedaries consists of individually variable periods of growth, maturation and regression. Deviation occurs 6.1±1.08d from emergence. Transrectal color-Doppler sonography is a useful technique for noninvasive evaluation of follicular vascularity in camels during various stages of the follicular wave. It provides additional information to assess the developmental stage and activity of the ovarian structures.