Optimization and Application of in Vitro Embryo Production Technologies to Enhance Genetic Improvement in Dairy Cattle in Ethiopia
Authors: Ali* Sayid 
Published: May 2024

The reproductive potential of newborn male and female calves is enormous. However, by natural breeding, only a fraction of the reproductive potential of the outstanding animals could be utilized. Assisted reproductive technologies enabled dairy and beef breeders to utilize the naturally endowed potential of the male and female animals. Nevertheless, the use of these technologies entails prior optimization of techniques and protocols for optimal use of breed improvement. Therefore, the underpinning concepts of the current research project were the optimization of in vivo oocyte collection, and media for Invitro embryo Production from the Boran and Boran*Holstein breed through ultrasound-guided ovum pickup. Through transvaginal follicular aspiration procedure, both breeds exhibited cultivable performance in owing substantial follicular population and relative tameness for aspiration procedures that can be tapped by these reproductive techniques. With the transvaginal follicular aspirations, the current study has revealed that a total of 1645 follicles ≥ 3mm were visualized, counted, and aspirated. From punctured and aspirated follicles, 889 oocytes were retrieved from both Boran and their Holstein crossbred cows with an overall recovery rate of 54.0%. Breed-wise, Boran and Crossbred cows were 51.9% (436/840) and 56.3% (453/805) respectively and no significant differences were observed between the Breeds in oocyte recovery rate. Furthermore, similar patterns of maturation process and embryo development were observed for an oocyte collected from both the Boran and Crossbred cattle. Whereas for the type of media used for in vitro oocyte maturation, fertilization, and culture oocytes were well matured, fertilized, and cultured giving promising results compared to TCM -199 media. Relative to the number of incubated oocytes, the lower maturation rate of both Boran and Crossbred cattle oocytes observed could be attributed mainly to media optimization and mainly maintenance of the culture environment in a new laboratory setup. The decrease in the number of mature oocytes that developed into zygotes uttered that the events around the time of maturation are crucial in determining the developmental competence of the oocyte. Uncontrolled factors such as power blackouts, laboratory equipment optimization, frequent opening and closing of CO2 incubators due to the availability of only one incubator, and fewer exposed lab technicians might have contributed to the low outcome of in vitro embryo culture. The cumulative effect of the extrinsic factors surrounding the oocyte and the intrinsic factor (quality of each oocyte) affected the outcome of maturation, fertilization, and development of the cultured zygote to the embryo. Though all procedures were started from scratch with minimal experience of technicians particularly transvaginal oocyte retrieval techniques and the IVF procedures showed the great potential of indigenous genetics. Thus, the sustainable improvement of the procedures by enhancing local and national capacity to run a full-fledged bovine IVF laboratory needs due attention.