Ultrasonographic assessment of the ovarian response in eCG-treated goats

Abstract

A study was conducted to evaluate the accuracy of ultrasonographic evaluation of ovulation rate during the early luteal phase of does and to estimate the reliability of ultrasonic scanning to differentiate between the corpus luteum and luteinized follicles. Both ultrasonographic and laparoscopic observations of ovarian structures and radioimmunoassays of progesterone in plasma were performed in 47 goats on day 7 after estrus synchronization using intravaginal FGA sponges and eCG. Ultrasonographic scanning allowed the determination of the presence or absence of ovulation. Total efficiency in detecting the occurrence of multiple ovulations was 87.5%. However, accuracy to establish the number of corpora lutea decreased to 23.5% in goats with three or more ovulations, due to an increasing underestimation as the number of corpora lutea in the ovary increased ( p<0.001). Ultrasonographic assessment of ovulation rate can be used to determine if a goat has ovulated or if multiple ovulations have occurred, but not to establish the precise number of corpora lutea. Evaluation of the ratio between cavity diameter and total luteal-tissue diameter is useful in distinguishing between corpora lutea and luteinized follicles, since the diameter differed between the two (0.36±0.21 vs. 0.64±0.16, respectively; p<0.005).