# Heart rate and heart rate variability of dairy cows with or without local anesthesia

## TL;DR

This study shows that using low-dose lidocaine for epidural anesthesia in cows does not affect heart rate variability, supporting its use as a stress indicator in animal welfare research.

## Contribution

The study validates HRV as a reliable welfare assessment tool in cattle undergoing epidural anesthesia.

## Key findings

- Low-dose lidocaine epidural injection did not alter HRV parameters in dairy cows.
- HRV changes observed during procedures can be attributed to stress, not anesthetic effects.
- Cows showed similar recovery times to baseline HRV values after both lidocaine and saline treatments.

## Abstract

Summary: This study investigated whether low-dose caudal epidural lidocaine administration affects cardiac autonomic regulation in dairy cows, a question crucial for validating heart rate variability (HRV) as a welfare assessment tool. Using a crossover design, 8 Holstein-Friesian cows received either 4 mL of 2% lidocaine or physiological saline via sacrococcygeal epidural injection. Heart rate and HRV parameters (root mean square of successive differences [RMSSD], high-frequency [HF], ratio of low-frequency and high-frequency components [LF/HF]) were monitored for 240 minutes postinjection using Polar V800 Polar Electro OY, Kempele, Finland) devices. Results showed no significant differences in area under the curve values for any HRV parameter between lidocaine and saline treatments. These findings demonstrate that sacrococcygeal epidural anesthesia does not detectably alter cardiac autonomic function in dairy cows. This validation supports the use of HRV analysis in welfare studies involving epidural anesthesia, confirming that observed HRV changes during procedures can be attributed to stress responses rather than anesthetic effects.

Summary: This study investigated whether low-dose caudal epidural lidocaine administration affects cardiac autonomic regulation in dairy cows, a question crucial for validating heart rate variability (HRV) as a welfare assessment tool. Using a crossover design, 8 Holstein-Friesian cows received either 4 mL of 2% lidocaine or physiological saline via sacrococcygeal epidural injection. Heart rate and HRV parameters (root mean square of successive differences [RMSSD], high-frequency [HF], ratio of low-frequency and high-frequency components [LF/HF]) were monitored for 240 minutes postinjection using Polar V800 Polar Electro OY, Kempele, Finland) devices. Results showed no significant differences in area under the curve values for any HRV parameter between lidocaine and saline treatments. These findings demonstrate that sacrococcygeal epidural anesthesia does not detectably alter cardiac autonomic function in dairy cows. This validation supports the use of HRV analysis in welfare studies involving epidural anesthesia, confirming that observed HRV changes during procedures can be attributed to stress responses rather than anesthetic effects.

•Caudal epidural lidocaine does not affect HRV in dairy cows.•HRV remains stable during epidural anesthesia, validating welfare studies in cattle.•The crossover design confirmed no autonomic effects from sacrococcygeal injection in cattle.•The low-dose technique preserves cardiac autonomic regulation in cattle.

Caudal epidural lidocaine does not affect HRV in dairy cows.

HRV remains stable during epidural anesthesia, validating welfare studies in cattle.

The crossover design confirmed no autonomic effects from sacrococcygeal injection in cattle.

The low-dose technique preserves cardiac autonomic regulation in cattle.

Heart rate variability analysis provides valuable insights into autonomic nervous system function but remains minimally explored in veterinary anesthesiology, particularly regarding its relationship with low-dose caudal epidural anesthesia in cattle. This study employed a crossover design to determine whether epidural lidocaine administration (4 mL of 2% solution) affects cardiac autonomic regulation compared with physiological saline in 8 healthy Holstein-Friesian dairy cows. Interbeat intervals were measured at baseline and for 240 min following epidural injection and cardiac autonomic activity-related parameters of heart rate variability (heart rate, root mean square of successive differences, high-frequency component, and ratio of low-frequency and high-frequency components) were calculated. Area under the curve for the first 240 min after the treatment and time to return to baseline were used to evaluate overall treatment effects on cardiac autonomic activity. Results revealed no differences in the area under the curve values for any parameters of heart rate variability between lidocaine and saline epidural interventions throughout the observation period, with comparable recovery times to baseline values between treatments. These findings suggest that sacrococcygeal epidural anesthesia did not detectably affect cardiac autonomic regulation in dairy cows under the conditions of this study.