title: Changes in blood pressure, heart rate, and blood profile in mares during the last 3 months of gestation and the peripartum period.
abstract: In this study, peripartum changes in complete blood count, plasma electrolyte concentrations, blood pressure, heart rate, and heart rate variability (HRV) were determined in pregnant Warmblood mares (n = 10). Blood was collected from Days 245 to 330 of gestation (phase A), 2Days 3 to 1 before foaling (phase B), repeatedly within 12 hours after foaling (phase C), and on Days 1 to 3 postpartum (phase D). On the same days as blood collection, blood pressure and cardiac beat-to-beat intervals were measured and time domain HRV variables were calculated. Blood pressure decreased during the past 3 months of gestation, reached a nadir at foaling and increased rapidly thereafter (P < 0.001). Heart rate increased in phase A, reached a maximum in phase B, and decreased directly after foaling (P < 0.001) while HRV increased transiently after foaling (P < 0.001). The number of polymorphonuclear granulocytes was higher during phases B, C, and D than that during phase A (P < 0.001) and total leukocyte numbers peaked in phase C (P < 0.001). Erythrocyte counts and hematocrit increased immediately after foaling with a rapid decrease thereafter (P < 0.001), while plasma total protein was highest 1 hour after foaling (P < 0.001). Sodium and chloride concentrations increased from phases A to C and decreased in phase D (P < 0.001). Calcium concentrations were lowest immediately after foaling. In conclusion, changes in cardiovascular function and a transient hemoconcentration occur in peripartum mares. These changes may favor adequate uterine perfusion.
authors.affiliation: Graf Lehndorff Institute for Equine Science, Vetmeduni Vienna, Neustadt/Dosse, Germany. Electronic address: christina.nagel@vetmeduni.ac.at.
authors.forename: Christina
authors.initials: C
authors.lastname: Nagel
authors.affiliation: Centre for Artificial Insemination and Embryo Transfer, Department for Small Animals and Horses, Vetmeduni Vienna, Vienna, Austria.
authors.forename: Lisa
authors.initials: L
authors.lastname: Trenk
authors.affiliation: Section for Obstetrics, Gynecology and Andrology, Department for Small Animals and Horses, Vetmeduni Vienna, Vienna, Austria.
authors.forename: Jörg
authors.initials: J
authors.lastname: Aurich
authors.affiliation: Graf Lehndorff Institute for Equine Science, Vetmeduni Vienna, Neustadt/Dosse, Germany.
authors.forename: Manuela
authors.initials: M
authors.lastname: Wulf
authors.affiliation: Centre for Artificial Insemination and Embryo Transfer, Department for Small Animals and Horses, Vetmeduni Vienna, Vienna, Austria.
authors.forename: Christine
authors.initials: C
authors.lastname: Aurich
mesh_terms: D000818:Animals; D001772:Blood Cell Count / Q000662:veterinary*; D001794:Blood Pressure / Q000502:physiology*; D004573:Electrolytes / Q000097:blood; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006736:Horses / Q000502:physiology*; D058725:Peripartum Period / Q000502:physiology*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000502:physiology
chemical_list: D004573:Electrolytes
keywords: Blood count; Blood pressure; Horse; Parturition; Plasma electrolyte