In vitro fertilization (IVF) and embryo transfer (ET) are highly practical embryo engineering techniques used for experimental manipulation and reproductive production of bovine embryos. Since the 1980s, when 0PU operation was performed under B-ultrasound monitoring, this technology has been widely used for in vitro production of bovine embryos. OPU technology has the advantages of wide application, convenient operation, high efficiency, repeatability, and minimal damage. By combining OPU and IVF technologies, the reproductive potential of high-quality cattle can be fully enhanced and high-quality embryos can be produced in large quantities.

Prior to the OPU procedure, the cow stood in a stable position, received 2mL lidocaine tail epidural anesthesia, and 1 mL of "846 mixture II" intramuscular injection. Remove rectal feces, clean the external genitalia, and disinfect the external genitalia with 0.1% chlorhexidine. Gently insert the probe with an egg collection needle into the vaginal vault, and the operator pulls the ovary through the rectal wall to the end of the probe. Based on the display screen image, adjust the position of the ovary and probe so that the ovary is on the puncture guide line, advance the egg collection needle, and use a foot switch to control the vacuum pump to suction follicular fluid at a pressure of about 100 mmHg (except for Experiment 1.3.4). Rinse the egg collection needle and catheter with DPBS (containing 3% BSA and% 2 U/mL heparin), and place the flushing solution into the collection tube. All follicles ≥ 2 mm were punctured, and the number of punctured follicles was recorded.

OPU provides a valuable method for in vitro production of high-quality bovine embryos. With the completion of bovine genome sequencing and the mapping of new quantitative trait loci [26I], the recovery of oocytes with clear genetic backgrounds through bovine 0PU will provide valuable experimental materials for studying bovine embryonic development at the molecular level, and ultimately have significant economic and practical value for producing high-quality bovine embryos.