BRONCHOALVEOLAR LAVAGE IN HORSES - EFFECT OF EXERCISE AND REPEATED SAMPLING ON CYTOLOGY

Bronchoalveolar lavage (BAL) was performed at weekly intervals in 10 T horoughbred horses in race training (group 1) and in 4 rested horses ( group 2) for 10 weeks. Lavages were continued on a weekly basis in 4 g roup 1 horses for an additional 9 weeks (group 3), Cytological analysi s of samples included leukocyte counts, erythrocyte counts, differenti al leukocyte counts, and haemosiderophage score. The mean leukocyte co ncentration was significantly lower in group 1 (92.1 +/- 4.6 cells/mu L) when compared with group 2 (133.5 +/- 8.2 cells/mu L), P = 0.037, T he differential leukocyte data were not significantly different betwee n groups, There was a large amount of variability in the percentage of macrophages and lymphocytes in the differential counts over time with no obvious trends, The proportion of neutrophils demonstrated a tende ncy to decrease over time for both groups 1 and 2, Erythrocyte counts and haemosiderin scores were significantly higher in the exercising gr oup than the rested horses, Neither exercise nor the technique itself evoked an inflammatory response in the BAL fluid.