Risk factor | Affected farms | Negative controls |
---|---|---|
Age of first occurrence of disease | 15.9a | 28.0a |
Age of clinical and necropsy examination | 24.8a | 32.5a |
Mortality at grow-out, % | 32.3 %a | 4.5 %b |
Presence of respiratory disease | 100 %a | 100 %a |
Presence of enteric disease | 100 %a | 0 %b |
Torticolis and neurological signs | 91.7 %a | 0 %b |
Haemorrhages in more than 1 visceral organ | 83.3 %a | 0 %b |
Thymus atrophy | 100 %a | 0 %b |
Bursal atrophy | 75 %a | 50 %b |
Ascites | 8.3 %a | 50 %a |
Air-sacculitis, perihepatitis and peritonitis | 16.7 %a | 50 %b |
Clouded air sacs | 50 %c | 100 %d |