INTERSPECIFIC TRANSFER OF IVM-IVF-DERIVED RED SHEEP (OVIS-ORIENTALIS-GMELINI) EMBRYOS TO DOMESTIC SHEEP (OVIS-ARIES)

Two embryo production methodologies were investigated to generate Red sheep embryos for use in an interspecific embryo transfer program. In Experiment 1, 4 multiparous female Red sheep (Ovis orientalis gmelini) were implanted with CIDR type G devices for 11 d. Forty-eight hours p rior to CIDR removal, a total of 22.5 mg bid of FSH-P was administered over a 3-d period. Laparoscopic embryo collection was performed 5 d p ost breeding, and embryos were transferred to domestic recipient ewes (Ovis aries and Ovis orientalis musimon). In Experiment 2, 7 nulliparo us female Red sheep were implanted with CIDR devices and injected with 200 IU of PMSG and 25 mg of FSH-P on the 8th day of implant insertion . At 60 to 70 h post PMSG/FSH-P treatment, follicular oocytes were asp irated laparoscopically. The recovered oocytes were matured in M199 (w ith fetal calf serum, FSH, LH, penicillin and streptomycin) at 39 degr ees C in a humidified atmosphere containing 5% CO2. At 24 h oocytes we re fertilized with frozen-thawed semen at a concentration of 1.6 X 10( 6) sperm/ml. The ova/embryos were placed in CR2 or BOEC culture medium at 20-22 h post IVF. Following 3 to 4 d in culture, embryos were tran sferred laparoscopically to the uterine horn of synchronized recipient s. In Experiment 1, 4 embryos and 6 UFO were collected from 2 embryo d onors, respectively. Two embryos were transferred with the aid of a la paroscope to each of 2 Rambouillet recipients, one of which gave birth to a healthy Red sheep lamb at 158 d of gestation. In Experiment2, a total of 62 oocytes was collected from 7 oocyte donors; 16 developed t o the 16- to 32-cell stage and were transferred to 8 recipients. Three of these IVM-IVF embryos were transferred laparoscopically to 2 Moufl on recipients, resulting in no pregnancies, Thirteen IVM-IVF embryos w ere transferred to 6 Rambouillet recipients. Each of these gave birth to a single healthy Red sheep lamb. Gestation lengths of the 3 IVM-IVF lambs ranged from 152 to 162 d. This research demonstrates that when using compatible species IVM-IVF technology in conjunction with inters pecific ET can lead to the production of live offspring and can be use d to propagate exotic ovine species.