Vaginal mucus conductivity as measured by the Walsmeta MKIV does not accurately predict the moment of ovulation or the optimum time for insemination in sows

The course of vaginal mucus conductivity (Walsmeta MKIV®, Masterbreeders (AI) Ltd., UK) during oestrus has been related to the moment of ovulation (determined with transrectal ultrasonography). Forty-four multiparous cycling sows were checked for oestrus and vaginal conductivity at 8 h intervals and for ovulation at 4 h intervals. In the course of oestrus the electrical conductivity of the vaginal mucus increases significantly (P < 0.01); however, conductivity at the start of oestrus or changes in conductivity during the first 8–24 h of oestrus cannot be used to predict the timing of ovulation or the duration of oestrus which is related to ovulation time. Use of the readings obtained with the Walsmeta would have led to 88% of the animals having been inseminated too early when the optimum timing for insemination is defined as the period 0–24 h before ovulation. It is concluded that the Walsmeta cannot be used to predict the moment of ovulation or the optimum time for insemination.