after slaughter, the rate of maturation was higher and the
rate of degeneration was lower than for oocytes collected
after transport of ovaries to the laboratory (Hinrichs et al.,
2005). Overall, between 40% and 50% of the oocytes
reach metaphase II when matured in TCM199 + 10% FCS
or DMEM/F12 + 10% serum replacement (Invitrogen);
both media are also supplemented with gonadotrophins
and growth factors (Galli et al., 2007; Lagutina et al.,
2005). A proportion (approximately 20%) of the oocytes
will not mature within the expected timeframe; some