Culture Conditions for the Development of Equine Oocytes

Assisted reproductive technologies (ARTs) are gaining more importance for both human fertility treatments and veterinary purposes. Furthermore, horses and other big mammals can be used as animal models for research in fertility and reproduction studies. In recent years, improvements in the efficiency and convenience of ovum pick-up (OPU), in vitro maturation (IVM), and intracytoplasmic sperm injection (ICSI) techniques in horses allowed the use of ARTs as routine research and commercial procedures. However, improvements are still needed to increase the rate of successful oocyte IVM, as different laboratories use different protocols with variable maturation rates. Here, we present the protocol that we optimized for in vitro maturation of equine cumulus-oocyte complexes (COCs), which is suitable for maturing oocytes for in vitro embryo production and obtaining mature oocytes for research purposes.