A PMSG/GnRH method for the superovulation of the monovulatory brush-tailed possum (Trichosurus vulpecula).

Optimal ovarian stimulation with minimal degenerative changes was achieved in brush-tailed possums 3 days after a subcutaneous injection of 10 i.u. PMSG. This treatment alone did not result in ovulation and only rarely in oocyte maturation. Ovulation of 8-24 mature oocytes occurred when on the 3rd day after 10 i.u. PMSG the female received 3 intramuscular injections of 50 micrograms synthetic gonadotrophin-releasing hormone (GnRH) 90 min apart. Superovulation was achieved in immature, cycling, pregnant and lactating females, but not in animals in the preovulatory phase of a natural oestrous cycle.