Table 1.
Parameters measured on piglet calls produced during manual restraint by a human or during crushing by sows during the first 48 h of life.
| Parameter | Description |
|---|---|
| Total Duration; s | Total time from the onset to the end of a call |
| Start to peak; s | Distance from the beginning of the call until the loudest element is reached |
| Peak Frequency; Hz | Loudest frequency found within a call |
| Peak Amplitude; dB | Measurement of the highest energy within a call |
| Minimum frequency; Hz | The lowest frequency within a call above the threshold (30 dB) |
| Maximum frequency; Hz | The highest frequency within a call above the threshold (30 dB) |
| Bandwidth; Hz | The difference between the minimum and maximum frequency |
| Fundamental frequency, Hz | Lowest frequency in a distinct harmonic structure |
| First formant, Hz | First detectable concentration of frequencies forming a band structure within a call |
| Second formant, Hz | Second detectable concentration of frequencies forming a band structure within a call |
| Quartile 25%; Hz | Frequency found at 25% of the total energy in call |
| Quartile 50%; Hz | Frequency found at 50% of the total energy in call |
| Quartile 75%; Hz | Frequency found at 75% of the total energy in call |
| Entropy | The randomness within a call where zero is a pure-tone and one is completely random noise |
| Harmonic-to-noise ratio | Ratio of the degree of harmonic sound to additional noise produced within a call |