WHEN SHIPPING FEVER STARTS
Effective screening for pleuropneumonia, commonly called shipping fever, may require longer follow-up after a transport than previously thought, according to an international study.
Researchers at Kitasato University in Towada, Japan, and the Equine Veterinary Medical Center at the Qatar Foundation in Doha, Qatar, monitored the body temperatures of 53 young Thoroughbreds and Anglo-Arabians during trips that lasted from 36 to 61 hours over three different study periods.
Riding in commercial trailers driven by professional haulers, the horses were given rest stops every four to five hours. Each horse was provided with a hay net and water but was not allowed to lower his head below knee height---a restriction that inhibits clearing of the airways and is known to increase the risk for shipping fever. Researchers traveling with the horses took their temperatures every three to five hours during the journey and one final time at the end of the trip.
Twenty-five of the study horses developed signs of shipping fever in the week after transport, but only 10 of those had fevers at the very end of the trip. This, the researchers note, “supports the suggestions that measuring body temperature upon arrival to determine the presence or absence of shipping fever could result in missed diagnoses for some horses with subclinical pneumonia.”
The highest incidence of fever occurred from 20 to 49 hours after the start of the trip, so continuing to monitor a horse’s temperature for that period, even if he is no longer traveling, “is a simple method for not missing horses with subclinical pneumonia,” the researchers conclude.
LATE ARRIVAL: A horse developing transport-related pleuropneumonia may not have a fever immediately after a long trailer ride.