Morphological study of tracheal shape in donkeys with and without tracheal obstruction.

The research aims to examine the tracheal shape of donkeys to understand if there are differences in those with and without tracheal obstructions. Utilizing post mortem examinations, the scientists discovered that donkeys, particularly those of older ages, frequently had some form of tracheal abnormalities, but these often did not cause health issues unless concurrent respiratory diseases were present.

Objective and Methods

• The study’s primary objectives were to investigate tracheal shapes in donkeys with and without evidence of tracheal obstruction, to measure tracheal size and shape and to gather data on prevalence, location and characteristics of detected tracheal abnormalities.
• The study involved post mortem examinations of the tracheas of 75 donkeys, mainly of older ages (median age 30 years, range 7-48 years). These animals had either died of natural causes or were euthanized on humane grounds.
• Five out of the seventy-five examined had severe breathing difficulties caused by tracheal obstruction, while seven showed post mortem evidence of severe tracheal obstruction.
• For each donkey, every 5th tracheal ring was dissected, and the inner and outer vertical and transverse dimensions and cross sections were measured. These dissected rings were then photographed and classified based on their shape and any structural abnormalities.

Results

• The average count of tracheal rings was 43 (range 34-50). The shape was more oval in the distal cervical region and circular to oval in 31.2% of all examined rings.
• The research team found various tracheal abnormalities, with dorso-ventral flattening in 0.9% of tracheal rings, dorsal ligament separation in 24.4%, slight cartilage deformity in 26.0%, moderate cartilage deformity in 10.4%, marked cartilage deformity in 1.9%, and miscellaneous other abnormal features present in 4.9% of tracheal rings.
• Donkeys showing ante or post mortem evidence of tracheal obstruction had a significantly higher grade of tracheal abnormality compared to the others.

Conclusion

• The research concluded that many older donkeys have structural tracheal abnormalities. However, these abnormalities typically do not lead to clinical issues if the donkeys do not also have concurrent respiratory illnesses.
• This understanding of tracheal morphology in donkeys could assist veterinarians and researchers in diagnosing and treating respiratory diseases in these animals more effectively.