Studies on the physiopathology of chronic obstructive pulmonary disease in horses. I. Clinical signs.

This research investigates the physical symptoms of chronic obstructive pulmonary disease (COPD) in horses, detailing how they differ from those in normal horses and how they’re not always reliable indicators of COPD.

Introduction and Methodology

• The study observed twenty horses showing symptoms of chronic coughing from the lungs and reduced performance.
• These horses were compared with a control group consisting of 38 horses that exhibited no clinical signs of disease.
• The researchers evaluated horses’ physical signs, like work tolerance, cough duration, pulmonary sounds, and abdominal expiratory efforts, to identify symptoms of COPD.

Results and Findings

• Based on the study, reduced work tolerance, persistent coughing (more than three months), and abnormal pulmonary sounds (known as râles) were identified as the primary signs of COPD in horses.
• More additional signs that could confirm the presence of COPD included forced abdominal expiratory efforts, and a symptom referred to as the ‘pumping of the anus’.
• However, the study found that not all observed signs are completely reliable in diagnosing the disease. For example, neither nasal discharge nor increased marginal distance were reliable signs of COPD.
• Moreover, the research also revealed notable differences in respiratory frequencies: the average respiratory frequency of the horses with COPD was significantly higher (25.4 breaths per minute) than that of the normal horses (16.7 breaths per minute).
• The statistical significance of this difference was noted as P < 0.001, indicating it's not due to random chance, but is a real, significant difference.

Conclusion

• The findings of this study provide valuable information that can help in diagnosing COPD in horses, although some clinical signs previously considered indicative of the disease were found to be unreliable.
• This emphasizes the importance of using a combination of clinical signs—particularly work tolerance, cough duration, abnormal pulmonary sounds, and forced abdominal expiratory efforts— and respiratory frequency levels for a more accurate diagnosis of COPD in horses.