Clinical Selection Criteria for Secondary Examinations of the Health‐Status of Broiler Flocks*

Abstract

Results of post-mortem and laboratory examinations of broilers sampled randomly or selected by clinical symptoms were compared. The male:female-ratio was in all cases nearly equal for randomly sampled and selected birds. Regarding post-mortem findings, differences dependent on selection criteria were observed: in randomly-sampled birds the frequency of breast-blisters and plantar inflammations was higher than in selected broilers, whereas in the latter osteodystrophy and bursal atrophy were seen more frequently. Alterations of joints and tendon-sheaths caused by a reovirus-arthritis in one flock were seen in same frequency in randomly sampled and selected birds, respectively. Parasitological examinations revealed the highest coccidial lesion scores in selected birds with lameness or slightly retarded growth but when dwarfism birds were included into calculations, there was no significant difference among both groups. Results of bacteriological and serological examinations showed no differences between the groups.