Somatic cell nuclear transfer with recipient oocytes derived from ovum pick up

The aim of this experiment was to determine whether it was feasible to produce embryos using a combination of somatic cell nuclear transfer (SCNT) and ovum pick up (OPU) and to determine whether use of transfected donor cells for cloning alters developmental potential of embryos. Heifers were subjected to OPU once weekly. In total, 1861 oocytes were recovered from 2436 follicles and recovery rate was 76.4% (7.8 ± 0.4 oocytes/session per animal). Oocytes were then subjected to SCNT (cumulus cell-NT, CC-NT; transfected cumulus cell-NT, TCC-NT) and in vitro fertilization (IVF). Cloned embryos derived from transfected donor cells had a similar in vitro developmental competence and a lower in vivo developmental competence compared with non-transgenic cloned embryos. Three cloned calves were obtained and survived for more six months. In conclusion, the combination of SCNT and OPU is feasible and genetic modification may exert a negative effect on pregnancy rates derived using the present protocol.