Morphometric Analysis of Ovaries and Follicles and Their Relationship with Oocyte Quality in Embryo Donor Cows

Abstract

This study aimed to evaluate the morphological characteristics of ovaries, follicles, and corpora lutea in heifers, primiparous, and multiparous cows using ultrasound, and to assess the potential of ultrasound for follicle quality evaluation in embryo donor cow selection. Thirty cows, of which there were 10 heifers, 10 primiparous cows, and 10 multiparous cows, were examined using a 5 MHz transrectal ultrasound probe (Caresono Technology Co., Ltd, HD 9300, China). In ten reproductive-age cows (2.5 to 5.5 years), corpora lutea were observed in 7 right ovaries, follicles in 2, and no structures in 1. In ten heifers, corpora lutea were present in 4 right ovaries, with 2 also exhibiting follicles. Left ovaries in heifers showed corpora lutea in 5 and follicles in 3. In ten late-parity cows, corpora lutea were found in 6 right ovaries, and follicles in 5. Left ovaries of late-parity cows showed corpora lutea in 6, follicles in 6, corpora lutea and follicles in 3, and 1 non-functional ovary. Heifers exhibited statistically significantly smaller right ovary length and width (p < 0.05) compared to primiparous and multiparous cows. The examination also revealed smaller left ovaries in heifers compared to the other examined cows, though the difference was not statistically significant. Ultrasound alone cannot contribute to making definitive decisions regarding the selection of embryo donor cows. Apart from determining ovarian morphometric characteristics, it is necessary to assess hormone concentrations, particularly Anti-Müllerian hormone.