Foetal Monitoring, Uterine Dynamics and Reproductive Performance in Spontaneous Farrowings in Sows

To determine the farrowing process and to evaluate the effect of parity on uterine dynamics and reproductive performance, 120 Yorkshire X Landrace hybrid sows, twenty for each parity number from 1 to 6 were used. Frequency, duration and intensity of contractions were monitored as indicators of uterine activity, foetal cardiac frequency (FCF) was monitored to determine fetal distress. Overall, farrowing duration was 189 min, contraction number and intensity were 40.9 and 9.89 mm Hg, respectively. Sixth parity sows had the shortest labor duration. The average number of fetuses with severe bradycardia and distress was 0.5. There was a significant increase (P=0.001) in the number of uterine contractions in gilts and second parity sows. First parity sows showed the highest intensity of contractions (12.30 mm Hg, P=0.001) and the largest number of delayed FCF decelerations, (0.90, P=0.004), which agrees too with a large average number of intra-partum stillbirths (0.90) found. The present study establishes the basic uterine dynamics of eutocic parturitions which may help in swine obstetrics to design uterotonic treatments reducing the stillbirth rate due to asphyxia. These findings emphasize a need for farrowing supervision, especially for first and over fifth parity sows.