Bacterial Burden in the Air of Indoor Riding Arenas

Airway diseases in horses are often multifactorial and have a strong environmental background because diseased horses react to inhaled agents. In this study, the air quality of closed riding arenas was analyzed monthly in four riding arenas over the course of one year with special emphasis on bacteriology. A standardized riding program with one horse was used to measure exposures to airborne bacteria. Air samples were taken from the heights of the riders’ and the horses’ breathing zone (2.5 m and 1.5 m, respectively) at four sampling points before and after the riding program. The bacterial loads in all four arenas significantly increased after the riding program. However, the results showed no differences between the breathing zones of the riders (2.5 m height) and those of the horses (1.5 m height). Gram-positive bacteria and especially Staphylococcus spp. occurred as the predominant aerobic mesophilic bacteria; 80% of the identified Staphylococci were Staphylococcus xylosus. The cultured samples from the ground of the arenas indicated that the ground was probably the main source of airborne Staphylococcus spp. during riding. The impact of an additional bacterial burden in riding halls on the health of riders and horses remains unknown; however, the air quality of riding arenas should be of special interest in future studies in terms of the high air consumption of horses during training periods.