Our hypothesis is that coughing horses have airway inflammation. Fifty horses – 36 coughing (Co Group)and 14 control (C Group) – of different gender, age, and function were evaluated. Physical and endoscopicexaminations, and cytological analyses of tracheal wash (TW) and bronchoalveolar lavage (BAL) fluids wereundertaken. Higher grades of tracheal mucus were observed in coughing horses. TW fluid neutrophil countwas higher (46.4% ± 30.8% vs. 19.5% ± 22.9%, p=0.003) in the Co group than the C group. In BAL fluid,neutrophil count was higher in the Co group than in the C group (30.3% ± 27.3% vs. 5.0% ± 4.2%, p=0.001,respectively). BAL fluid cytological profile compatible with inflammatory airway disease (IAD), recurrentairway obstruction (RAO), and normal were evidenced in 14 (38.9%), 17 (47.2%), and 5 (13.9%) of theevaluated coughing horses. IAD was diagnosed in 6 horses of the C group. Cough is a clinical sign of airwayinflammation in horses.

The immunological status of the respiratory tract is critical to racehorses’ performance. Respiratory diseases in young Thoroughbred (TB) racehorses are a major concern during their early athletic career. This study investigated the airway adaptations occurring in young TB race horses during their first year of race training. Eighteen animals were evaluated at five different time points over a one-year follow-up period. A physical examination was performed, followed by airway endoscopy, in which tracheal mucus (TM) and pharyngeal lymphoid hyperplasia (PLH) were observed. Differential cytology of the tracheal wash (TW) was also performed. The physical parameters in the five assessments and TM grade did not vary. The PLH grade was lower at time-points 3 (T3) and 4 (T4) than at the initial evaluation (T0) (P=0.028 and P=0.036, respectively). The cytological analysis revealed that neutrophil count decreased at T4 as compared with T0 (P=0.022). Epithelial cell count was increased, and macrophage count decreased, at T3 and T4, compared with T0 (P=0.004 and P=0.031, respectively). Haemosiderophage count was higher at T1 (P=0.020) and lower at T2 (P=0.003), compared to T0. A statistical correlation between mucus and all cell types was found, showing a non-specific immune response. In conclusion, young TB racehorses underwent airway modifications during the initial months of race training, and a thorough follow-up is needed during the initial period after stabling.

As afecções do trato respiratório inferior constituem a segunda maior causa de atendimentos na clínica dos equinos, sendo a tosse uma manifestação comum. O presente estudo teve como objetivo mostrar a importância do uso concomitante dos lavados traqueal (LT) e broncoalveolar (LBA) na avaliação de cinco cavalos apresentando tosse espontânea, como auxílio para diagnóstico preciso, importante para a determinação do tratamento mais adequado. Cinco cavalos, entre quatro e dezesseis anos de idade, de diferentes raças e atividades, foram avaliados por meio de exame físico, endoscópico e avaliação citológica de LT e LBA. No LT, 80% dos cavalos avaliados apresentaram processo inflamatório, resultado que aumentou para 100% no LBA. Adicionalmente, a avaliação citológica do LBA auxiliou na diferenciação diagnóstica entre doença inflamatória (DIVA) e obstrução recorrente (ORVA), das vias aéreas. A utilização associada do LT e do LBA fortaleceu o diagnóstico das doenças inflamatórias das vias aéreas dos cavalos. Sugere-se a avaliação completa dos cavalos com doenças das vias aéreas, por meio de exame físico e associação das técnicas citológicas com o LT e LBA.

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