TY - JOUR

T1 - Influence of transrectal and transabdominal ultrasound examination on salivary cortisol, heart rate, and heart rate variability in mares

AU - Schoenbom, Hanno

AU - Kassens, Ana

AU - Hopster-Iversen, Charlotte

AU - Klewitz, Jutta

AU - Piechotta, Marion

AU - Martinsson, Gunilla

AU - Kissler, Andreas

AU - Burger, Dominik

AU - Sieme, Harald

PY - 2015/3/1

Y1 - 2015/3/1

N2 - 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. (C) 2015 Elsevier Inc. All rights reserved.

AB - 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. (C) 2015 Elsevier Inc. All rights reserved.

KW - Mare

KW - Stress

KW - Transrectal ultrasonography

KW - Transabdominal ultrasonography

KW - Cortisol

KW - PLASMA-CORTISOL

KW - ADRENAL AXIS

KW - STRESS

KW - RESPONSES

KW - HORSES

KW - OXYTOCIN

KW - RELEASE

KW - LACTATION

KW - PROLACTIN

KW - PREGNANCY

U2 - 10.1016/j.theriogenology.2014.11.010

DO - 10.1016/j.theriogenology.2014.11.010

M3 - Journal article

VL - 83

SP - 749

EP - 756

JO - Theriogenology

JF - Theriogenology

SN - 0093-691X

IS - 4

ER -