Table 1.
Attributes used for the classification of stress in pigs.
| Attribute | Unit | Description |
|---|---|---|
| Sex | - | Male or Female |
| Distress | - | Normal (baseline), pain, cold and hunger |
| Signal energy | Pa²*s | Energy emitted in the sound wave |
| Signal duration | S | Duration of the sound wave |
| Maximum range | Pa | Maximum range of the sound wave |
| Minimum range | Pa | Minimum range of the sound wave |
| Intensity | dB | Sound wave intensity |
| Pitch frequency | Hz | Determines the pitch level |
| First formant | Hz | First formant frequency |
| Second formant | Hz | Second formant frequency |
| Third formant | Hz | Third formant frequency |
| Fourth formant | Hz | Fourth formant frequency |
| Range | Pa | Difference of maximum and minimum ranges |
| Sum of the formants | Hz | Sum of the 4 formants frequencies |
| Average formants | Hz | Average of the 4 formants frequencies |
| F3-F4 | Hz | Difference between the 4th and 3rd formants frequencies |
| F4-F2 | Hz | Difference between the 4th and 2nd formants frequencies |
| F4-F1 | Hz | Difference between the 4th and 1st formants frequencies |
| F3-F2 | Hz | Difference between the 3rd and 2nd formants frequencies |
| F3-F1 | Hz | Difference between the 3rd and 1st formants frequencies |
| F2-F1 | Hertz | Difference between the 2nd and 1st formants frequencies |
| Sum of the differences | Hertz | Sum of the differences between the formants |
| Average of the differences | Hertz | Average of the differences between the formants |