Fetal heart rate and fetal heart rate variability in Lipizzaner broodmares.

This research investigates the fetal heart rate and heart rate variability in Lipizzaner mares during pregnancy, providing insights into normal and pathological conditions in the foal. The study found significant changes in these rates as the pregnancy progressed and raised possibilities for further research into the application of these parameters in clinical and stud settings.

Research Objectives and Methodology

• The main aim of the research was to establish reference values for normal heart rate during Lipizzaner mares’ pregnancy and do a time-domain analysis of heart rate variability (HRV).
• The study involved seventeen mid-to-late term (from 121 to 333 days) Lipizzaner mares. They were examined using fetomaternal electrocardiography (ECG), a non-invasive technique to monitor fetal heart rate.

Key Findings

• The researchers discovered that both the FHR (Fetal Heart Rate) and HRV decreased significantly as the pregnancy progressed. This is contrary to previous equine studies, indicating further research in this area is warranted.
• The data indicated an overall decrement in FHR ± SD values from 115 ± 35 to 79 ± 9 bpm between the 5th and 11th month of pregnancy. The SDNN (standard deviation of normal-normal intervals) appeared to be higher than what has been previously reported.
• The RMSSD (root mean square of successive differences), a measure of variability in heart rate, decreased from 105 ± 69 to 77 ± 37 msec between the 5th and 11th month of gestation. This might again suggest that the equine fetal heart rate and its variability modify as the pregnancy advances.
• Through the use of telemetric ECG equipment, the researchers were able to detect an equine fetal heartbeat as early as day 121 of the pregnancy. This breaks new ground in equine fetal monitoring techniques.
• The study also found large variations in heart rate values among four mare-fetus pairs over four consecutive months. This suggests the possibility of ‘high-HR’ and ‘low-HR’ fetuses in horses, a new area for exploration in equine research.

Conclusion and Future Work

• The study concluded that the monitoring of FHR and FHRV offers promise as a tool to assess fetal well-being in horses. However, it noted that the application of these parameters in clinical and stud settings requires further investigation.
• This pioneering work opens up opportunities for more extensive studies in the field and the development of useful veterinary diagnostics and treatments for Lipizzaner mares and other breeds.