We know that long-hauls trips can have a negative impact on horses’ respiratory systems and increase their risk of associated infections. But what about the shorter trips we take more frequently—to a local show down the road or to the neighboring town for lessons? As it turns out, researchers have not yet studied the effect of short distance trips on horses.

“The question is: Does it create low-degree inflammation that could influence test results when horses are evaluated for respiratory problems?” said study author Mathilde Leclere, DVM, PhD, Dipl. ACVIM, an assistant professor at the University of Montreal Faculty of Veterinary Medicine, in Quebec, Canada.

Leclere anticipated that her team’s recent study would reveal higher bacteria counts in the horse’s windpipe following a short trip, but it simply was not the case, she said. In the study, the team examined healthy horses transported in the same trailer over the same countryside roads for two and half hours on two occasions, with or without hay. While bacteria numbers were not increased following transportation, lung inflammation was higher following some, but not all, transports.

“We cannot say for sure what transport conditions induce airway inflammation because here, horses without hay in the trailer had more inflammation than horses with hay, which is counterintuitive,” she said