The effect of induced standing reflex, cervical stimulation and insemination on intraluminal pressure variations in the isthmus of the oviduct in unrestrained gilts.

Four gilts were each equipped with 2 ultra-miniature pressure sensors, placed at 2 different points along the same isthmus of the oviduct, on the morning of the first day of standing oestrus (Day 1). Intraluminal pressure recordings were started the same afternoon. After an initial recording period, intraluminal pressure was recorded while the gilts showed standing oestrus and during cervical stimulation followed by insemination with either 100 ml saline or 100 ml boar semen. Monitoring of the pressure variations in the isthmus was continued for up to 6.5 h after the last insemination. Blood samples for monitoring oestradiol-17 beta, progesterone and 15-ketodihydroprostaglandin F2 alpha were collected before and after each manipulation of the gilt and every 30 min during the rest of the test period. None of the above manipulations had any consistent effect on the intraluminal pressure in the porcine isthmus, although, a clear 15-ketodihydroprostaglandin F2 alpha peak could be seen after insemination with boar semen.