EN
The aim of the study was to improve the methods of recovery, maturation and fertilization in vitro (IVМ/IVF) of lamb oocytes in order to get offspring from prepubertal donors. Oocytes were obtained from 4-9-week-old lambs, oocytes from slaughtered adult ewes were run in parallel as control. Ewe lambs received subcutaneous implants (1 mg norgestomet) for 5 days. At the time of implant removal the animals were injected with FSH and PMSG. After 24 h oocytes (60 per donor) were collected by laparotomy under general anesthesia. Oocytes were matured and fertilized in vitro 24 hours after IVЕ, presumptive zygotes were transferred to the intermediate recipients for 6 days. From 9 definitive recipients which received 18 blastocysts, 8 were confirmed pregnant by scanning performed on days 35 and 60. One sheep has already delivered two normal lambs.