The impacts of obesity on the avian respiratory system

To visualize and describe the anatomy of the lower respiratory system in obese and nonobese white cockatoos, red-tailed hawks, and New World vultures, and discuss the use of current body condition scoring (BCS) methods in avian veterinary practice.

Using micro-CT of live, sedated obese and nonobese birds, 3D anatomical models were built to visualize and extract air sac volumes. All live birds were imaged for clinical purposes unrelated to this specific study, and the DICOM image stacks were later donated to the project.

Internal adipose tissue affected the volume and displacement of the air sacs in all obese birds examined. In obese and egg-bearing specimens, the caudal group of air sacs (abdominal and caudal thoracic) was compressed, resulting in a reduced total volume, while the cranial group of air sacs (cervical, interclavicular, and cranial thoracic) and their diverticula often expanded into the cervical and axillary regions.

The effects of obesity on air sac volume and shape varied in the birds examined, and further work is needed to determine the functional implications of these differences. Additionally, current avian BCS methods do not account for internal adipose distribution or its potential anatomical effects in avian patients.

Excess internal adipose may alter air sac volume and displacement patterns, with potential implications for clinical and perioperative management. Species-specific BCS methods should be employed when possible to assess obesity in birds.