Cannulation for a bovine fetus in late gestation under regional anesthesia

摘要

This experiment was carried out to collect fetal blood and fluid via catheters fitted to elucidate interaction between the mother and her fetus during a comparatively long term. Fifteen cows in late gestation were used for this study. Under regional anesthesia, an incision was made in the left paralumbar fossa in the standing position. A catheter for fetal blood was inserted into a vein of the fetus and catheters for fetal fluid were inserted into amniotic and allantoic sacs respectively. Four types of catheters were used for collecting fetal blood. The best of these catheters for fetal vein was the angiographic catheter covered with spring tube. Fetal blood samples were able to be collected for more than seven days constantly from four fetuses until parturition. Fetal fluid could be collected daily from three fetuses until parturition perfectly. Parturition occurred at the end of a normal gestation period. The concentration of fetal and maternal cortisol decreased to the basal level within 24 hours (P<0.05) after operation. The changes in fetal and maternal cortisol during periparturition were the same as previously reported. These results suggested that this method would be beneficial for fetal cannulation and the sample collected by this method was useful for endocrine study during the perinatal period in cattle.