The oocytes were fixed 18 h after insemination, and 29 out of 48 oocytes (60 %) were fertilized.48 h after insemination the cleavage, > 4 cell and > 8 cell rate and on day 8 after insemination the blastocyst formation rate have been scored. (Quelle: bmb+f Forschungslandkarte Deutschland 1998)