Rezác Petr, Pöschl Michael, Krivánek Ivo
Department of Morphology, Physiology and Veterinary Medicine, Mendel University of Agriculture and Forestry, Zemedelská 1, 61300, Brno, Czech Republic.
Theriogenology. 2003 Mar;59(5-6):1325-34. doi: 10.1016/s0093-691x(02)01168-8.
The impedance technique is one of many methods that can be used for noninvasive monitoring of reproductive events occurring in cyclic animals. The influence of the depth of probe insertion on changes in vaginal impedance in sows during the estrous cycle was examined. Sows were checked twice a day for estrus via exposure to a sexually mature boar. The criterion for confirmation of ovulation was an increase in plasma progesterone levels above 4.0 ng/ml 8 and 12 days after the beginning of estrus. The impedance measurements were carried out using a four-terminal method at a distance of 8, 10, 12, 14, 16 and 18 cm from the vulva. In all six locations of the vagina the mean impedance values decreased gradually after weaning (P<0.01), achieved a nadir 1-2 days before estrus and increased during estrus (P<0.01). It was found that the probe location within the vagina and the parity of sows significantly affected the impedance measured by means of a four-terminal method. The study suggests that the causes of impedance fluctuation are not only technical but also include a number of poorly understood biological causes.
阻抗技术是可用于对处于发情周期的动物所发生的生殖事件进行无创监测的多种方法之一。本研究考察了探头插入深度对母猪发情周期中阴道阻抗变化的影响。通过让母猪接触性成熟公猪，每天对母猪进行两次发情检查。确认排卵的标准是发情开始后8天和12天血浆孕酮水平升高至4.0 ng/ml以上。使用四端法在距离外阴8、10、12、14、16和18 cm处进行阻抗测量。在阴道的所有六个位置，断奶后平均阻抗值逐渐下降（P<0.01），在发情前1-2天达到最低点，并在发情期间升高（P<0.01）。研究发现，探头在阴道内的位置以及母猪的胎次显著影响通过四端法测量的阻抗。该研究表明，阻抗波动的原因不仅有技术方面的，还包括一些尚不清楚的生物学原因。
