Stress response and cardiac activity of term and preterm calves in the perinatal period.
This study tested the hypothesis of gestational age affecting fetal cardiac activity and the stress response at birth. Heart rate (HR), heart rate variability variables, SD of the beat-to-beat interval and root mean square of successive beat-to-beat differences, and postnatal salivary cortisol concentration were studied in calves born at term (Term, n = 7, gestation length 286.3 ± 2.1 days) or after induction of parturition (Preterm, n = 7, gestation length 279.6 ± 0.2 days). Observation periods covered the last month of gestation (phase A), the last hours before birth including the first stage of labor (phase B), and the neonatal period (phase C). Fetal HR decreased in phase A (P < 0.001) and did not differ between groups. During phase B, HR increased (P < 0.05) and was higher in Preterm than in Term calves in phases B (P < 0.05) and C (P < 0.01). In Term calves, heart rate variability increased from Day 6 until birth (P < 0.05). At birth, SD of the beat-to-beat interval was higher in Term than in Preterm calves (P < 0.01). On Day 1 after birth (phase C), HR accelerations were more frequent in Term than Preterm calves (P < 0.01), whereas decelerations were more frequent in Preterm calves (P < 0.05). Cortisol concentration increased postnatally (P < 0.001) and was correlated with gestation length (r ≥ 0.68, P < 0.01). Because of a certain degree of immaturity, the ability to cope with the stress of birth may be impaired in calves born 1 week before term.
Centre for Artificial Insemination and Embryo Transfer, Vetmeduni Vienna, Vienna, Austria. Electronic address: christina.nagel@vetmeduni.ac.at.
Christina
C
Nagel
Division for Obstetrics, Gynecology, and Andrology, Vetmeduni Vienna, Vienna, Austria.
Jörg
J
Aurich
Centre for Artificial Insemination and Embryo Transfer, Vetmeduni Vienna, Vienna, Austria.
Lisa
L
Trenk
Centre for Artificial Insemination and Embryo Transfer, Vetmeduni Vienna, Vienna, Austria.
Natascha
N
Ille
Clinical Unit for Heard Health Management in Ruminants, Vetmeduni Vienna, Vienna Austria.
Marc
M
Drillich
Kremesberg Research and Teaching Farm, Vetmeduni Vienna, Vienna Austria.
Werner
W
Pohl
Centre for Artificial Insemination and Embryo Transfer, Vetmeduni Vienna, Vienna, Austria.
Christine
C
Aurich
D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001724:Birth Weight; D002417:Cattle; D005260:Female; D005865:Gestational Age; D006339:Heart Rate / Q000502:physiology*; D006340:Heart Rate, Fetal / Q000502:physiology*; D006854:Hydrocortisone / Q000032:analysis; D007751:Labor, Induced / Q000662:veterinary; D007743:Labor, Obstetric / Q000502:physiology; D036801:Parturition / Q000502:physiology; D011247:Pregnancy; D012463:Saliva / Q000737:chemistry; D013312:Stress, Physiological / Q000502:physiology*
D006854:Hydrocortisone
Calf; Cattle; Cortisol; Fetus; Heart rate; Heart rate variability