Rewiring the luteal microenvironment: hemodynamic and molecular insights into eCG-supported CL development in indigenous White Lamphun cattle

This study tested whether a small dose of equine chorionic gonadotropin (eCG), a hormone naturally produced during pregnancy in horses, can enhance ovarian function in native Thai cattle. We added eCG to a short estrous synchronization program, a hormone-based protocol used to align the timing of ovulation among cows within a few days, and evaluated key reproductive processes: egg release (ovulation), development of the CL, a temporary gland formed after ovulation that secretes progesterone (P4), a hormone essential for establishing and maintaining early pregnancy, and blood flow to the CL. We also measured hormone levels and the activity of genes involved in forming new blood vessels. Cows that received eCG showed stronger ovarian activity, including larger preovulatory follicles, more robust CL development, better ovarian blood flow, and higher P4 levels. Genes related to vascular growth were also more active. These findings indicate that low-dose eCG supports CL function and ovarian physiology and may help improve the efficiency of breeding management in local cattle.