[Folliculogenesis and embryo transfer in ruminants]

In ruminant embryo transfer development, the limiting step remains the superovulation of the donor: using both PMSG and pituitary extracts, the superovulatory response is variable. In our research unit, FSH and LH were purified until homogeneity. Superovulatory treatment includes the administration of pure FSH the day following the preovulatory LH pulse and an administration of an LH/FSH mixture in the middle cycle. This biphasic stimulation of folliculogenesis allows superovulatory response with more and higher quality embryos.