Uterine motility of cows during advanced pregnancy, calving and the puerperium. I. Spontaneous motility
Kundig, H.; Thun, R.; Zerobin, K.; Bachmann, B.
Schweizer Archiv für Tierheilkunde 132(2): 77-84
In four cows, pressure microsensors and electrodes were surgically implanted into the pregnant horn three to four weeks prior to calving. During the final two to three weeks of gestation, only isolated weak uterine contractions were recorded, sometimes associated with activity by the fetus. Frequency and amplitude of waves of contraction began to increase about 18-20 h ante partum, the waves being then tubo-cervically directed, becoming extremely strong when the fetus entered the birth canal, and particularly during expulsion of the calf. Uterine motility was drastically reduced following expulsion of the placenta, only increasing again by the second week after calving.