The problem of partial or complete failure of fertilization following cervical insemination in superovulated ewes submitted for embryo transfer can largely be overcome by depositing semen directly into the uterine lumen. However this technique, when carried out by mid-line laparotomy in superovulated ewes is associated with a significant reduction in ovum recovery (Trounson & Moore, 1974; Boland & Gordon, 1978). Although the recent introduction of laparoscopic intrauterine (IU) insemination has now removed the need for major surgery when inseminating superovulated ewes its use in non-superovulated ewes often results in a slight depression in litter size (McKelvey, Robinson, Aitken & Henderson, 1985). Such results imply that it too may reduce embryo recovery rates. Indeed our initial experience with the widespread use of the laparoscopic technique to inseminate superovulated ewes, although devoid of proper conventionally-inseminated controls, gave disappointingly low values for embryo recovery.

The present study was carried out therefore to determine the effect of direct intrauterine versus natural cervical insemination on egg recovery and fertilization rates in ewes superovulated using porcine FSH or PMSG and GnRH.