With the globalization of horse racing, racehorses are frequently shipped long-distances via airplane or horse trailer. Transport-associated fever is a common and potentially serious issue that can disrupt training and racing schedules or indicate an infection, potentially leading to pneumonia or pleuropneumonia. So, veterinarians, researchers, and owners alike are in search of ways to reduce a horse’s likelihood of developing transport-associated fever.

Recently, Yoshiro Endo, DVM, of the Japan Racing Association’s Hidaka Training and Research Center, in Hokkaido; Seiji Hobo, DVM, PhD, of Kagoshima University; and colleagues investigated the effects of administering 2 mg/kg of marbofloxacin (MRFX) to healthy Thoroughbreds prior to long-distance transport. Another group of horses received saline and served as controls.

The team determined that MRFX was significantly more effective than saline in protecting against transport-associated fever.

Still, this new quinolone (synthetic broad-spectrum antibacterial) antibiotic isn’t the be-all and end-all of transport-associated fever prevention. Antibiotic use raises concerns about the potential for resistant bacteria and, as a result, the Japanese Ministry of Agriculture, Forestry and Fisheries restricts MRFX use. Endo said the rule targets cattle, but still applies to horses, as well; “We think that this rule is unnecessary,” he added.

To reduce the chances of resistant bacteria development, Endo recommended the following guidelines for using MRFX in association with long-distance transport: “MRFX should only be used at transportation and only for long periods