CT-assisted versus silicone rubber cast morphometry of the lower respiratory tract in healthy amazons (genus Amazona) and grey parrots (genus Psittacus).

The objective of this study was to examine the normal respiratory tract of grey parrots and amazons by using two different methods. The lower respiratory tract of five amazons and four grey parrots, all healthy, were investigated applying computerised tomography (CT). Volumes and densities of the body, the body cavities, the normal lungs, and the airsacs in the living animals were defined as reference values of healthy birds to give a basis for future CT-diagnosis of respiratory diseases and their precise locations in parrots. In a parallel study, the lung and air sac volumes of six amazons and two grey parrots were measured using silicone rubber casts produced after the method described by H.-R. Duncker. Values for identical respiratory structures gained by these different methods were compared.