The deposition of semen under laparoscopic visualisation directly into the uterine lumen alleviates the problem of low fertility in superovulated ewes. However, we have recently demonstrated that intrauterine insemination when carried out at 52 h after progestagen pessary withdrawal results in a significant reduction in the percentage of embryos recovered. This observation seemed to suggest that intrauterine insemination, the timing of which was chosen to coincide with ovulation, is interfering with collection of the oocytes by the fimbria or altering the rate of oocyte transport. The present experiment was carried out to test this hypothesis by assessing ovum recovery and fertilization rates following intrauterine insemination unilaterally in the right horn only or bilaterally, at either 48 or 60 h after progestagen pessary withdrawal.

Twenty-five Finnish Landrace x Dorset Horn ewes were studied during seasonal anoestrus in May 1988. Ewes were individually penned under natural lighting conditions (57°N 2°W) and were offered 1.4 kg per day of a complete diet supplying 9 MJ of metabolizable energy/kg.