Clinical parameters
Since the two main complaints reported by the owners were poor performance and coughing, then the dataset further sub-divided horses into four groups based on clinical symptoms:
Group 1: no clinical symptoms,
Group 2: poor performance,
Group 3: coughing,
Group 4: both poor performance and coughing (Table 1).
Referring veterinarians were requested for the clinical examination (temperature, pulse, respiration and lung auscultation) and details of the endoscopic examination, including: TMS, BAL volume as well as BAL volume aspirated.
Referring veterinarians were given a protocol on how to perform the endoscopic examination, including how to score mucus and the BAL volume to use (Appendix 1).
Tracheal mucus score (TMS) for each horse was based on a qualitative ordinal scoring system ranging 0-5 (Gerber et al., 2004b) (0 = no mucus, 1 = small blobs, 2 = multiple blobs, 3 = stream-forming, 4 = pool-forming and 5 = profuse amount). A TMS ≤2 was considered acceptable in healthy sports horses (Couetil et al., 2016). Initial BAL volume used was standardized to 200-250 ml, and the amount aspirated as a percentage of the volume instilled was calculated. Based on the results, horses were sub-divided normal BAL cytology or diagnosed with either MEA or SEA based on alternative BAL cytology reference values (Couetil et al., 2016) and differences in the aspirated volume between EA diagnoses were explored.