The experiments describe simple and effective methods used for the production of sheep embryos in vitro. The oocytes isolated from the ovarian follicles, 2-5 mm in diameter, were matured in culture for 22-24 h. After mixing with ram spermatozoa pretreated with heparin, 77-100% of fertilized oocytes were monospermic. Some of them (60-68.3%) cleaved in culture after 24-50 h to 2-4-cell stage. The transfer of cleaved embryos to the oviducts of 4 synchronized recipients resulted in pregnancies and 4 normal lambs were born at term.

Department of Genetics Czechoslovak Academy of Sciences Libĕchov