Stages of Embryo Development
| Zygote: Fertilized egg (about 20 hours after insemination) |
| 2 cell embryo (about 20 hours after insemination) |
| 4 cell embryo (about 48 hours after insemination) |
| 8 cell embryo (about 72 hours after insemination) |
| Morula: 16-32 cell embryo (about 96 hours after insemination) |
| Blastocyst stage embryo (about 115 hours after insemination) |

