Ultrasonic transit-time measurement of blood flow in the umbilical arteries and veins in the bovine fetus during stage II of labor

Effect of xylazine, isoxsuprine, and lidocaine on Doppler sonographic uterine and umbilical blood flow measurements in cows during the last month of pregnancy

“…Epidural anesthesia with lidocaine also increased blood flow to the maternal portion of the placenta, and because there were no systemic adverse effects in the fetus, this treatment may have potential usefulness in intrauterine resuscitation. It seems that in a cow with dystocia, the elimination of strong contractions could improve placental perfusion considering that venous blood flow to the fetus is impaired during a contraction [11]. In contrast, xylazine should be given to cows in the final stage of pregnancy or during parturition only after careful consideration because of the risk of transient fetal hypoxia.…”

“…There has been one study on umbilical blood flow in calves during parturition using sonographic transducers fixed to the umbilical vessels [11], and several others in canine, equine and ovine fetuses [12][13][14][15][16]. showed an increase in RI in the last few weeks of gestation [13].…”

Transabdominal ultrasonographic evaluation of fetal well-being in the late-term mare and cow

“…Venous blood flow is more severely affected than arterial blood flow during strong contractions because the walls of the umbilical veins are thinner and have fewer muscle fibres than those of the umbilical arteries. Umbilical arterial and venous blood flow in acidotic calves was lower than that in non-acidotic calves during the last 30 minutes before birth (Bleul et al, 2007).…”

“…It also allows us to investigate the relationships between umbilical blood flow, uterine contractions and fetal heart rate (Bleul et al, 2007). A decrease in blood flow is most likely caused by compression of the umbilical vessels during uterine contractions.…”

The relation between the birth process and the condition of the newborn piglet and calf

“…The latter is caused by hyperstimulation of uterine contractions, because plasma oxytocin reaches peak levels at this late stage of delivery (Hydbring et al 1999), and by involution of the now unoccupied distal part of the uterine horn. A recent study, using ultrasonic transit-time measurements of umbilical blood flow during second stage labour, demonstrated that in calves born with a jugular blood pH<7.2, umbilical blood flow significantly decreases at the end of the expulsive stage; blood flow in the umbilical arteries and vein even ceased completely during passage of the calf's head through the vulva (Bleul et al 2007). This corresponds rather well with earlier observations by our own group that in acidotic calves the baseline foetal heart rate significantly increases during the final hour before birth and that jugular plasma catecholamine levels in such calves are significantly higher at birth than in nonacidotic newborns (Jonker et al 1996).…”