Stabling is associated with airway inflammation in young Arabian horses

We examined the effect of stabling on upper and lower airway inflammation i n 14 yearling Arabian horses that had been at pasture since birth, Horses w ere divided into 2 groups of 7, One group was stabled for 3 months and the other remained at pasture. The groups were then switched over for another 3 months. The nasopharynx, guttural pouches and trachea were examined endosc opically and bronchoalveolar lavage performed every month. An upper airway inflammation score was devised based on the magnitude of pharyngeal lymphoi d hyperplasia and guttural pouch inflammation. During stabling this score r emained constant, whereas it decreased during the 3 months at pasture, Stab ling was also associated with a higher number and percentage of neutrophils in bronchoalveolar lavage fluid and with a smaller percentage of lymphocyt es, There was no correlation between upper airway inflammation score and br onchoalveolar ravage cytology, During a nasal occlusion test, dorsal displa cement of the soft palate occurred more times in stabled than in pastured h orses, but this was heavily biased by the results from one animal, We concl ude that stabling is associated with inflammation of both the upper and low er airway of young horses.