Schönbom Hanno, Kassens Ana, Hopster-Iversen Charlotte, Klewitz Jutta, Piechotta Marion, Martinsson Gunilla, Kißler Andreas, Burger Dominik, Sieme Harald
Clinic for Horses-Unit for Reproductive Medicine, University of Veterinary Medicine Hannover, Hannover, Germany; National Stud Lower Saxony, Celle, Germany.
Clinic for Horses-Unit for Reproductive Medicine, University of Veterinary Medicine Hannover, Hannover, Germany.
Theriogenology. 2015 Mar 1;83(4):749-56. doi: 10.1016/j.theriogenology.2014.11.010. Epub 2014 Nov 13.
Pregnancy diagnostics in equine reproduction are routinely performed using transrectal ultrasonography, although it is also possible to visualize the fetus by transabdominal ultrasound examinations from the 90th day of gestation onward. We hypothesized that ultrasound examinations may stress the mare and that the gestational stage status and lactation may influence the mare's stress reaction. To investigate the stress reaction, 25 thoroughbred mares of different age, pregnancy and lactational status underwent a transrectal examination. In pregnant mares, an additional transabdominal examination was performed. Salivary cortisol concentration, mean heart rate, and heart rate variability of mares were assessed to evaluate the reactions of hypothalamic-pituitary-adrenal (HPA) axis and of the autonomic nervous system. Significant differences were observed between lactating and nonlactating mares; with a lower responsiveness to stress in lactating mares. The transrectal ultrasound examination in nonlactating mares induced a significant increase in salivary cortisol (P < 0.05), and in the heart rate variability parameter, ratio of low to high frequencies (P < 0.05). This reflects an activation of the HPA axis and a shift to more sympathetic dominance. In contrast, a transabdominally performed pregnancy check did not induce an activation of the HPA axis over basal level but increased the mean heart rate and low to high frequency ratio. The results of this study indicate that checks of advanced pregnancies can be easily performed by transabdominal ultrasonography. With regard to animal welfare, this technique should be preferred during midgestation in nonlactating mares.
在马的繁殖中，妊娠诊断通常采用经直肠超声检查，不过从妊娠第90天起，也可以通过经腹超声检查观察到胎儿。我们推测超声检查可能会使母马产生应激反应，并且妊娠阶段状态和泌乳情况可能会影响母马的应激反应。为了研究应激反应，对25匹不同年龄、妊娠和泌乳状态的纯种母马进行了经直肠检查。对于怀孕母马，还进行了一次经腹检查。评估了母马的唾液皮质醇浓度、平均心率和心率变异性，以评估下丘脑 - 垂体 - 肾上腺（HPA）轴和自主神经系统的反应。在泌乳母马和非泌乳母马之间观察到了显著差异；泌乳母马对应激的反应较低。非泌乳母马的经直肠超声检查导致唾液皮质醇显著增加（P < 0.05），以及心率变异性参数低频与高频之比显著增加（P < 0.05）。这反映了HPA轴的激活以及向更为主导的交感神经状态的转变。相比之下，经腹进行的妊娠检查并未导致HPA轴超过基础水平的激活，但增加了平均心率和低频与高频之比。本研究结果表明，晚期妊娠检查可以通过经腹超声检查轻松进行。就动物福利而言，在非泌乳母马妊娠中期应优先采用这种技术。
