Heart rate and heart rate variability in horses undergoing hot and cold shoeing.

This research article explores the impact of two different shoeing methods (cold and hot) on the heart rate variability (HRV) of horses, an indicator of autonomic responses. Notable differences in various HRV components were observed, indicating that hot shoeing tends to increase the sympathovagal activity in horses more than cold shoeing.

Study Design and Participants

• The study was designed to compare the HRV variables in horses that underwent either cold or hot shoeing procedures.
• Two groups of horses were taken, with 25 horses undergoing cold shoeing and 26 horses undergoing hot shoeing.

Measurement and Comparison of HRV Variables

• The researchers measured multiple HRV variables, which included time, frequency, and nonlinear variables, at various points – before, during, and after shoeing at 30-minute intervals up to 120 minutes.
• These variables were then compared between the horses that underwent cold and hot shoeing.

Results and Observations

• The study showed that the shoeing method significantly influenced various HRV variables over time, such as the standard deviation of RR intervals (SDNN), root mean square of successive RR interval differences (RMSSD), low-frequency band (LF), total power, and others.
• Hot shoeing particularly increased SDNN, RMSSD, and total power after 30 minutes and also increased LF, SD1 and SD2 after 30-60 minutes.
• Triangular interpolation of normal-to-normal intervals (TINN) and the HRV triangular index notably increased during the hot shoeing procedure and up to 120 minutes afterward while TINN increased only during cold shoeing.
• The study also found that SDNN, TINN, HRV triangular index, LF, total power, and SD2 were higher in hot-shoed horses than cold-shoed horses throughout the 120 minutes post-shoeing.
• This indicated a significantly increased sympathovagal activity in horses that underwent hot shoeing compared to those that underwent cold shoeing.

Implications and Conclusion

• The study showed distinct differences in HRV variables between hot and cold shoeing methods, indicating that the type of shoeing has a direct impact on the physiological responses of horses.
• Given the evident increase in sympathovagal activity in horses subjected to hot shoeing, it becomes crucial to understand the implications of this on the overall health of the horses and adapt practices accordingly.