Table 1. Summary of data collected from the questionnaire and Environment Canada weather stations for the analysis of the occurrence of breast myopathies.
| Variables obtained from questionnaire to processing plants (24 questions) |
|---|
| Farm variables |
| • Feed type (categorical)† |
| •Lighting program (categorical) † |
| • Number of floors in a barn (1 or >2, categorical) |
| • Forward sortation area (FSA) of growers and hatcheries (categorical) ‡ |
| Flock demographics variables |
| • Age (d, continuous) |
| • Average live weight at slaughter (g, continuous) |
| •Breed (categorical) † |
| • Sex (categorical) |
| • Sources of chicks (categorical) |
| Flock health variables |
| • Disease observed (categorical) |
| • Mortality rate during grow-out (%, continuous) |
| • Raised without antibiotics (categorical) |
| • Vaccination and medication records (categorical) |
| Transportation from farms to processing plant variables |
| • Birds per crate (b/c, continuous) |
| • Dead-on arrival (%, continuous) |
| • Feed withdrawal time* |
| • Water withdrawal time* |
| • Time of load start* |
| • Time of load end* |
| • Truck travel time (min, continuous) |
| Processing plant variables |
| • Hold time on lairage at plant (min, continuous) |
| • Time of exsanguination* |
| •Exsanguination to deboning time (min, continuous) † |
| • Condemnation (%, continuous) |
| Variables obtained from Environment Canada weather stations |
| Environmental variables |
| •Average temperature during grow-out and transport (°C, continuous) |
| • Precipitation during grow-out and transport (mm, continuous) |
| • Season (categorical) |
* The processing plants provided the times of each event, and these times were used to calculate the duration of specific segments (S1 Fig).
† Variables were excluded from further analyses because of lack of variability.
‡ Questions on egg storage time and incubation temperature were asked but not answered.