Bovine oocytes were studied after being injected with sperm to understand their development. The researchers found that when treated with ethanol, over 70% of injected oocytes started developing. However, many sperm heads remained condensed, affecting the development process. Only about half of the injected oocytes reached the 2-cell stage, and even fewer progressed to the 8-cell stage compared to normal fertilization. The study also showed that a significant portion of oocytes developed parthenogenetically, which means they started developing without sperm. This suggests that the low success rate of bovine oocyte development after injection is mainly due to this type of activation.