Table 3.
Mean (± SD) heart rate and heart rate variability measurements of dairy calves given a hiding place (hide) or not (no hide) before (baseline; first 5-min lying bout in the hour preceding separation) and during (separation; 5 min after dam removed) the 60-min period of temporary separation from the dam. The change between the separation and baseline periods (separation – baseline) is also indicated
| Treatment | |||
|---|---|---|---|
| Hide | No hide | P-value | |
| Baseline period | |||
| HR (bpm) | 130.2 (± 15.6) | 143.0 (± 13.8) | 0.06 |
| R-R Interval (ms) | 466.2 (± 52.0) | 422.8 (± 38.1) | 0.06 |
| RMSSD 1 (ms) | 9.4 (± 3.5) | 7.1 (± 5.0) | 0.19 |
| LF:HF 2 | 17.9 (± 15.0) | 18.4 (± 23.7) | 0.34 |
| SD2/SD1 | 2.8 (± 1.6) | 3.7 (± 1.9) | 0.29 |
| PNS Index | –3.5 (± 0.4) | –3.8 (± 0.4) | 0.09 |
| SNS Index | 8.4 (± 1.4) | 11.24 (± 3.4) | 0.06 |
| Separation period | |||
| HR (bpm) | 143.7 (± 17.8) | 158.0 (± 18.3) | 0.11 |
| R-R Interval (ms) | 422.8 (± 49.3) | 383.8 (± 41.9) | 0.11 |
| RMSSD (ms) | 9.6 (± 5.9) | 5.2 (± 2.6) | 0.10 |
| LF:HF | 31.6 (± 37.2) | 28.8 (± 21.8) | 0.34 |
| SD2/SD1 | 4.2 (± 3.0) | 3.2 (± 0.9) | 0.47 |
| PNS Index | –3.7 (± 0.3) | –4.2 (± 0.3) | 0.02 |
| SNS Index | 8.9 (± 1.4) | 13.4 (± 4.3) | 0.02 |
| Change between baseline and separation periods | |||
| HR (bpm) | 13.5 (± 25.5) | 17.9 (± 1.1) | 0.40 |
| R-R Interval (ms) | –43.3 (± 74.0) | –39.0 (± 40.1) | 0.40 |
| RMSSD (ms) | 0.2 (± 8.1) | –2.0 (± 6.6) | 0.50 |
| LF:HF | 13.7 (± 38.9) | 10.4 (± 32.9) | 0.34 |
| SD2/SD1 | 1.3 (± 3.1) | –0.5 (± 2.5) | 0.09 |
| PNS Index | –0.2 (± 0.6) | –0.4 (± 0.2) | 0.50 |
| SNS Index | 0.5 (± 2.1) | 2.2 (± 2.8) | 0.24 |
1
RMSSD = Root mean squared of successive differences in the R-R interval
2
LF:HF = low frequency (0.04–0.29 Hz) to high frequency (0.30–0.80 Hz) ratio