Oviductal isthmic motility patterns as monitored by Polyview (TM) in unrestrained sows around ovulation

A method for monitoring oviductal isthmic motility in sows incorporating a computer programme (Polyview(TW)) was developed. This method was found to b e reliable and easy for recording and analysing data. Isthmic motility patt erns were monitored from 11 h prior to and up to 36 h after ovulation in 13 unrestrained multiparous sows during their second oestrus after weaning. T he amplitudes and frequencies of phasic pressure fluctuations in relation t o the hormonal profiles were also calculated. The isthmic motility patterns were regular before ovulation changing to wave patterns during the peri-ov ulatory period and eventually to irregular patterns after ovulation. The am plitudes and frequencies of phasic pressure fluctuations were significantly higher (p < 0.05) prior to and soon after ovulation than afterwards. Plasm a oestradiol-17 beta levels significantly (p < 0.05) decreased before ovula tion while plasma progesterone levels increased significantly (p < 0.05) af ter ovulation. Despite a significant decrease in the plasma levels of oestr adiol-17 beta prior to ovulation, the amplitudes and frequencies of phasic pressure fluctuations remained high until shortly after ovulation. This cou ld have been due to the endogenous levels of oestradiol-17 beta bound to th e nuclear oestradiol-17 beta receptors that might still have been present i n the isthmus. Conversely, the irregular isthmic motility patterns, the dec line in the. frequencies of phasic pressure fluctuations and amplitudes see n after ovulation may have been due to the rising plasma levels of progeste rone. The amplitudes and frequencies of phasic pressure fluctuations were h ighest at the time when oestradiol-17 beta levels were highest and when pro gesterone levels were low. It can be concluded that the changes in the isth mic motility patterns, amplitudes and frequencies of phasic pressure fluctu ations in relation to the changes in the plasma levels of oestradiol-17 bet a and progesterone seen in the present study prior to and after ovulation