Superovulation and Embryo Quality in Majorera Goat: Bibliographic Review and Experimental Trial

Abstract

The goat sector is currently at the peak of its progress and development in new techniques. This is why the best possible offspring are being studied, which can be achieved through superovulation techniques of genetically superior goats and their embryos can be transferred to recipient females. This can be achieved by implementing oestrus synchronisation treatments for all participating animals, both donors and recipients, either through intravaginal sponges or with internal controlled drug release devices (CIDR) placed inside the vagina, both impregnated with drugs (mostly progesterone) and maintained for 7-14 days. Subsequently, donor females are superovulated with eCG (single dose), FSH (6-8 doses spaced 12 hours apart) or a combination of both, with better results in protocols using multiple doses of FSH. This is because it results in higher ovulation and embryo recovery rates, as well as more transferable embryos. Nevertheless, it is a more laborious protocol and causes more stress to the animals as they have to undergo two injections per day 12 hours apart for 3-4 days. Once achieved, the next step would be the removal of embryos from the donors with the application of surgical, laparoscopic or non-surgical techniques. Among these techniques, the non-surgical technique is considered the safest for the animals. However, the laparoscopic technique is faster and causes less damage to the reproductive tract. These embryos can be transferred fresh to recipient females directly, preserved for the future or shipped anywhere in the world. This is where the preservation of these embryos takes on special importance, with cryopreservation being of particular importance, which has two methods: controlled slow freezing or vitrification (ultra-rapid freezing with liquid nitrogen). Cryopreservation allows for safe trade in health and reduced transmission of possible diseases or deaths, as only embryos and not live animals are shipped.