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.
Copyright © 2016 Elsevier Inc. All rights reserved.
Publication Date: 2016-06-14 PubMed ID: 27393220DOI: 10.1016/j.theriogenology.2016.06.001Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
The research documents the variations in blood pressure, heart rate, blood profile, and heart rate variability in pregnant horses towards the end of gestation and during the peripartum period.
Study Methodology
The study involved taking blood samples and varying physiological measurements from ten pregnant Warmblood mares at different stages of pregnancy and postpartum:
- Days 245 to 330 of gestation (Phase A)
- Two to one day before giving birth (Phase B)
- Within 12 hours after giving birth (Phase C)
- One to three days postpartum (Phase D)
In these phases, researchers collected data on blood pressure, heart rate, and heart rate variability (HRV), alongside measuring levels of different types of blood cells and plasma electrolytes.
Key Findings
- Blood pressure of the horses decreased in the last three months of gestation, reached the lowest point at birth, and then increased rapidly.
- The mares’ heart rates escalated in phase A, peaked in phase B, and declined after giving birth.
- Significant fluctuations in heart rate variability were also observed, with an increase spotted just after birth.
- The count of polymorphonuclear granulocytes, a type of white blood cell, was higher during phases B, C, and D compared to phase A. The number of total leukocytes peaked in phase C.
- Red blood cell count and hematocrit rose immediately after birth, followed by a swift reduction.
- Plasma total protein reached its maximum one hour after birth.
- Sodium and chloride concentrations escalated from phases A to C and decreased in phase D. Calcium concentrations were lowest after birth.
Conclusion
These findings indicate that significant changes in cardiovascular function, along with a temporary increase in the concentration of blood cells (hemoconcentration), occur in horses around the time of birth. These changes are postulated to potentially enhance appropriate blood flow to the uterus.
Cite This Article
APA
Nagel C, Trenk L, Aurich J, Wulf M, Aurich C.
(2016).
Changes in blood pressure, heart rate, and blood profile in mares during the last 3 months of gestation and the peripartum period.
Theriogenology, 86(7), 1856-1864.
https://doi.org/10.1016/j.theriogenology.2016.06.001 Publication
Researcher Affiliations
- Graf Lehndorff Institute for Equine Science, Vetmeduni Vienna, Neustadt/Dosse, Germany. Electronic address: christina.nagel@vetmeduni.ac.at.
- Centre for Artificial Insemination and Embryo Transfer, Department for Small Animals and Horses, Vetmeduni Vienna, Vienna, Austria.
- Section for Obstetrics, Gynecology and Andrology, Department for Small Animals and Horses, Vetmeduni Vienna, Vienna, Austria.
- Graf Lehndorff Institute for Equine Science, Vetmeduni Vienna, Neustadt/Dosse, Germany.
- Centre for Artificial Insemination and Embryo Transfer, Department for Small Animals and Horses, Vetmeduni Vienna, Vienna, Austria.
MeSH Terms
- Animals
- Blood Cell Count / veterinary
- Blood Pressure / physiology
- Electrolytes / blood
- Female
- Heart Rate / physiology
- Horses / physiology
- Peripartum Period / physiology
- Pregnancy
- Pregnancy, Animal / physiology
Citations
This article has been cited 8 times.- Czyżewska-Dors E, Wierzchosławski K, Pomorska-Mól M. Serum Concentrations of Immunoglobulins and Cortisol Around Parturition in Clinically Healthy Sows and Sows with Postpartum Dysgalactia Syndrome (PDS). J Vet Res 2022 Jun;66(2):245-250.
- Tavares Pereira M, Nowaczyk R, Aslan S, Ay SS, Kowalewski MP. Utero-Placental Immune Milieu during Normal and Aglepristone-Induced Parturition in the Dog. Animals (Basel) 2021 Dec 19;11(12).
- Kaiser M, Dahl J, Jacobsen S, Jacobson M, Andersen PH, Bækbo P, Escribano D, Cerón JJ, Tecles F. Changes of adenosine deaminase activity in serum and saliva around parturition in sows with and without postpartum dysgalactia syndrome. BMC Vet Res 2021 Nov 18;17(1):352.
- Cruz-Aleixo AS, Castro Ferreira Lima M, Holanda DE Albuquerque AL, Tortorelli Teixeira R, Alves DE Paula R, Grandi MC, Laurenti Ferreira DO, Harumi Tsunemi M, Biagio Chiacchio S, Gomes LourenÇo ML. Heart rate variability in Dorper sheep in the fetal and neonatal periods until 120 days of age: Use of the technique in the field. J Vet Med Sci 2021 Jan 14;83(1):17-27.
- Nagel C, Melchert M, Aurich C, Aurich J. Differences in Endocrine and Cardiac Changes in Mares and Her Fetus before, during, and after Parturition in Horses of Different Size. Animals (Basel) 2020 Sep 4;10(9).
- Kaiser M, Jacobson M, Andersen PH, Bækbo P, Cerón JJ, Dahl J, Escribano D, Jacobsen S. Inflammatory markers before and after farrowing in healthy sows and in sows affected with postpartum dysgalactia syndrome. BMC Vet Res 2018 Mar 12;14(1):83.
- Suwannarueang S, Pongkan W, Pontaema T, Kenchaiwong W, Pongthaisong P, Chompoosan C, Lerdweeraphon W. Cardiac adaptations in early equine pregnancy: heart rate elevation without heart rate variability alteration in Thai native crossbred mares. Vet World 2025 Sep;18(9):2590-2597.
- Chompoosan C, Pongthaisong P, Kenchaiwong W, Pontaema T, Lerdweeraphon W. Effects of pregnancy on electrocardiographic, vasovagal tonus index, and echocardiographic variables in horses. Vet World 2023 Aug;16(8):1765-1771.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
