Vol. 12, Special Issue 8 (2023)

Author(s):
Preeti, Anjali, Akshata Patil, Rajeshwari, Abhishek Bhardwaj and Jayanthi KV

Abstract:
Reproductive biotechnologies and genetic improvement programmes, have emerged as a strategy for increasing animal production. Ovum pick-up (OPU) has evolved as popular reproductive biotechnology in cattle from super stimulation and boosts maternal contribution to genetic improvement. OPU leads to significant genetic selection, and has decreased the time interval between generations and increased herd productivity. Following in vitro maturation (IVM), the majority of oocytes (90%) will enter metaphase II (M-II) and extrude the first polar body; about 80 percent will progress through fertilization and cleave to the two-cell stage. However, only 30–40 percent of embryos will ever develop into blastocysts. This would imply that the lengthiest phase of the in vitro embryo production process, the post-fertilization phase, is the key factor affecting blastocyst output. This is incorrect, as the percentage of immature oocytes those form the blastocyst is determined by events that occurred earlier along the developmental axis. The quality of blastocysts that do form is greatly influenced by the post-fertilization culture period, with in vitro created blastocysts continuously being of lower quality than their in vivo produced counterparts. The task is to alter the settings in our in vitro cultures for producing embryos in an effort to replicate those that naturally occur in vivo and so enhance blastocyst quality.