Equine pulmonary disease: a case control study of 300 referred cases. Part 1: Examination techniques, diagnostic criteria and diagnoses.

The research reports on a detailed examination into equine pulmonary diseases, with a particular focus on Chronic Obstructive Pulmonary Disease (COPD), across 300 referred adult horses. Different diagnosis methods were used to identify the cause of reduced performance or prolonged breathing difficulties after racing.

Study Methodology

• The study was conducted on 300 adult horses referred from 1990 to 1993 for pulmonary examination.
• A mix of diagnostic techniques were used to diagnose the horses. These included standardised history taking, clinical examination, intrapleural pressure test, arterial blood gases, and bronchoscopic and tracheal and broncho-alveolar lavage fluid (BALF) cytological examinations.
• Out of the 300 horses, 235 were referred due to overt signs of pulmonary disease, and the remaining 65 were referred due to reduced performance (typically in racing) or prolonged dyspnoea (breathing difficulty) after racing.

Results and Findings

• The examinations revealed no pulmonary disease in 30 cases. Out of the remaining 270 diagnosed with pulmonary disease, the majority (148 cases, 54.8%) was Chronic Obstructive Pulmonary Disease (COPD).
• In addition to COPD, other identified diseases included infectious or post-infectious pulmonary disease constituting 16.7% of the cases, Streptococcus zooepidemicus pulmonary infection at 2.6%, lungworm infection at 2.6%, and primary exercise-induced pulmonary haemorrhage (EIPH) at 5.9%.
• A few horses (3.3%) were diagnosed with chronic idiopathic hypoxaemia, and 7.4% had different identified pulmonary disorders. 6.7% suffered from undifferentiated pulmonary disorders where the specific disease could not be determined.
• The researchers also observed 2 cases of primary summer associated obstructive pulmonary disease (SPAOPD), and found that 9.5% of horses suffering from COPD also had SPAOPD.

Conclusion

The research revealed a high prevalence of COPD among the studied horses. It also brought attention to the other types of pulmonary diseases that may affect race horses’ performance, underscoring the importance of early detection and diagnosis for effective performance management and maintenance of overall equine health.