Brochoalveolar lavage in donkey: diagnostic procedures and clinical findings

Donkeys and horses usually share similar respiratory problems. Nevertheless, donkeys developed some anatomical differences with horses mainly related to upper airways [1] allowing to reduce their susceptibility to respiratory distresses as well as clinical signs severity [2]. For early diagnosis, the bronchoalveolar lavage (BAL) could represent an useful diagnostic procedure although the technique was never described before in these animals. The goals of the present investigation were to describe for the first time BAL procedures in healthy donkeys and to evaluate the related clinical findings. Nine, healthy, large size, female donkeys, with means (±SD) body weight of 338±61kg, wither height of 135.8±6.6cm and thoracic girth of 150.7±10.2cm were enrolled. All of them were submitted to complete clinical examinations (with particular focus on the cardio-respiratory system) and video-endoscopy. After sedation, based on acepromazine maleate 1% (0.025mg/kg IV) and Xylazine hydrochloride 20% (0.8 mg/kg IV), BAL was performed using the “blind technique” and an administration of 120 ml of Ringer lactate at 37°C. At the end of the procedure, the fluid collected was submitted for macroscopic and microscopic evaluation and differential cells count [3]. Blood and parasitological analysis were also performed. BAL was easily performed in all the subjects. Several epithelial cells (ciliated cells of various type and goblet cells, ranged: 11.2 33%; means±SD: 49.55±14.48), some macrophages (21- 46.50%; 71.66±16.31), few neutrophils (0.5-23.5%; 19.33±18.78), rare lymphocytes (12-47%, 55,44±15,54), and very rare eosinophils (0-5.25%, 4±3,9) were detected. The technique required analogous level of animal handling reported for horses and no obvious difficulties have been observed. Nevertheless, because of the anatomical differences of the upper airways between the two species [1,4], a good extension of the head (until to create a straight line with the spine) has been necessary both to facilitate the procedure and to use catheters usually employed for horses otherwise too long for donkeys. Blood investigations revealed normal values in all the subjects while coprological examination were positive for gastrointestinal strongyles in all them, although no larvae in the alveolar bronchial fluid were detected. BAL’s samples allowed to perform a differential count of the cells present in the lower airways of the animals. The means cellular values observed in healthy donkey were significant different from those one described for healthy horses [3]. The difference observed may be related to different specie-specific inflammatory response mechanisms between the two species although further investigation are warranted to confirm this hypothesis