Improve pronucleus formation in zygote derived from Bos gaurus dead sperm and Bos taurus small oocytes by pre-maturation culture

Growing oocytes derived from small antral follicles (2-3 mm) have poor maturation rates and developmental competence compared to fully grown oocytes collected from large antral follicles (4-6 mm). Hence, a pre-in vitro maturation (Pre-IVM) subculture with in vitro maturation (IVM) was applied to support small oocytes growth.