Factors Affecting Ovum Pick-Up (OPU) in Friesian Cattle: A Review

Abstract

Ovum pick-up (OPU) combined with in vitro embryo production (IVEP) has become an important reproductive biotechnology in dairy cattle breeding programs. The technique allows repeated recovery of oocytes from valuable donor animals, thereby accelerating genetic improvement and increasing reproductive efficiency. Friesian cattle, owing to their high milk-producing potential, are extensively utilized in OPU programs worldwide. However, the success of OPU depends on several biological, environmental, nutritional, hormonal, and technical factors that influence follicular development, oocyte quality, and embryo production. This review summarizes the major factors affecting OPU efficiency in Friesian cattle, including age, genetic background, nutrition, hormonal stimulation, follicular dynamics, heat stress, health status, operator expertise, and management practices. Understanding these factors is essential for optimizing oocyte recovery and improving the outcomes of assisted reproductive technologies in dairy herds.