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Home / Equine Research Bank / Animals (Basel) / Differences in Endocrine and Cardiac Changes in Mares and He...
Animals : an open access journal from MDPI2020; 10(9); 1577; doi: 10.3390/ani10091577

Differences in Endocrine and Cardiac Changes in Mares and Her Fetus before, during, and after Parturition in Horses of Different Size.

Abstract: Equine fetomaternal monitoring is based on endocrine and cardiac parameters which may differ among small, medium-size, and full-size horses. Therefore, Shetland ( = 6), Haflinger ( = 8), and Warmblood pregnancies ( = 9) were studied during late gestation and at foaling. Weight of mares, foals and placenta, plasma progestin and cortisol concentration, heart rate and heart rate variability (HRV) were determined. Foal weight always approximated 10% of mare weight but relative placenta weight was highest in full-size mares ( < 0.05). Progestin ( < 0.001) and cortisol ( < 0.05) concentration was highest in full-size mares. Progestin concentration decreased towards parturition ( < 0.001) while cortisol concentration increased ( < 0.01). Maternal heart rate increased before foaling with the most pronounced increase in small mares ( < 0.001). The HRV increased during foaling and decreased when delivery was completed ( < 0.001). Changes were most pronounced in full-size mares ( < 0.001). Atrio-ventricular blocks regularly occurred in parturient full-size mares but only occasionally in medium-size and small mares (time < 0.05, time × group < 0.05). This may reflect breed differences in cardiovascular efficiency. Fetal heart rate decreased towards birth ( < 0.001) with the most pronounced decrease in full-size horses ( < 0.01). Fetal HRV showed no consistent changes before birth but increased when the foal was born ( < 0.001), this increase being most pronounced in full-size foals ( < 0.05). In conclusion, this study demonstrates both similarities and differences in peripartum endocrine and cardiac changes in horses of different size.
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Publication Date: 2020-09-04 PubMed ID: 32899617PubMed Central: PMC7552300DOI: 10.3390/ani10091577Google Scholar: Lookup
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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 study focuses on understanding the differences in hormonal and cardiovascular changes in horses during pregnancy and childbirth, with particular emphasis on comparing these changes across different sizes of horses, namely Shetland, Haflinger, and Warmblood breeds.

Methodology and Parameters Studied

  • The researchers studied pregnancies of Shetland, Haflinger, and Warmblood horses during late gestation and at the time of foaling.
  • The parameters evaluated were the weight of the mares, foals, and placenta, plasma concentration of progestin and cortisol (two important hormones), heart rate, and heart rate variability (HRV) of both the mares and foals.

Differential Findings amongst Horse Breeds

  • The studies revealed that the weight of foals was approximately 10% of the mother’s weight irrespective of the breed. However, the relative weight of the placenta was found to be the highest in Warmbloods, the largest breed in the study.
  • Furthermore, the levels of progestin (a hormone that helps maintain pregnancy) and cortisol (a stress hormone) were found to be highest in Warmbloods to maintain pregnancy in full-size mares.
  • Also showed that the heart rate of the mothers increased before foaling (birth), and this increase was most pronounced in the Shetland breed, the smallest of the horses studied.
  • Heart rate variability (HRV), a measure of variation in the time interval between heartbeats, was seen to increase during delivery and decrease once delivery was complete.
  • Atrio-ventricular blocks, a type of heart condition, were regularly observed in the parturient Warmblood mares while they were just occasional occurrences in the smaller breeds, suggesting breed differences in cardiovascular efficiency.
  • Another important finding was a decrease in the fetal heart rate as birth approached, with the most significant drop observed in full-size horses, and a substantial increase in fetal HRV when the foal was born, again most pronounced in full-size horses.

Conclusion

The study was able to identify both similarities and differences in hormonal and cardiovascular responses before, during, and after birth in horses of different sizes. These findings can be used to optimize reproductive management and monitoring of pregnant mares and might eventually contribute to a better understanding of the equine peripartum period.

Cite This Article

APA
Nagel C, Melchert M, Aurich C, Aurich J. (2020). Differences in Endocrine and Cardiac Changes in Mares and Her Fetus before, during, and after Parturition in Horses of Different Size. Animals (Basel), 10(9), 1577. https://doi.org/10.3390/ani10091577

Publication

Animals : an open access journal from MDPI
ISSN: 2076-2615
NlmUniqueID: 101635614
Country: Switzerland
Language: English
Volume: 10
Issue: 9
PII: 1577

Researcher Affiliations

Nagel, Christina
  • Graf Lehndorff Institute for Equine Science, Vetmeduni Vienna, 16845 Neustadt (Dosse), Germany.
Melchert, Maria
  • Artificial Insemination and Embryo Transfer, Department for Small Animals and Horses, Vetmeduni Vienna, 1210 Vienna, Austria.
Aurich, Christine
  • Artificial Insemination and Embryo Transfer, Department for Small Animals and Horses, Vetmeduni Vienna, 1210 Vienna, Austria.
Aurich, Jörg
  • Obstetrics, Gynecology and Andrology, Department for Small Animals and Horses, Vetmeduni Vienna, 1210 Vienna, Austria.

Conflict of Interest Statement

None of the authors of this paper have financial or personal relationships with other people or organizations that could inappropriately influence or bias the content of the paper.

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