Olympic Transport

How would you like to have a dozen or so concise, easy-to-understand pages put together as a how-to of keeping your horse healthier and what to do before, during, and after you load your horse in a trailer and ship him? Include some


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How would you like to have a dozen or so concise, easy-to-understand pages put together as a how-to of keeping your horse healthier and what to do before, during, and after you load your horse in a trailer and ship him? Include some fill-in-the-blank charts telling you exactly what you should monitor on what day to make sure you don’t miss any signs of illness after your horse travels. Then have some of the leading researchers and veterinarians from around the world tell you in plain English over a half-dozen or so pages the risk factors of which you should be aware. For those of you with curious minds, add 80 or so pages that recap research from around the world on transporting horses, including studies from Japan that never before have been published or translated.

This amazing little book is entitled Guidelines for Horse Transport by Road & Air, and it was published this spring in response to last year’s inaugural meeting of the International Workshop on Equine Transport, sponsored by the Nevins Farm and Equine Centre of the Massachusetts Society for the Prevention of Cruelty to Animals (MSPCA)(see sidebar below).

“The purpose of the initial meeting was to review what has been written on transport and see what we know, then see what questions need to be answered,” said Catherine Kohn, VMD, Dipl. ACVIM, editor of the book.

The initial meeting was a “think tank” to define areas that need research. Since everyone ships horses at some time, it would be of great benefit to the entire industry if owners knew risk factors of transportation, and knew what factors had the greatest impact on transported horses.

“The other objective of the meeting was to put forth initial guidelines to tell horse owners what things are important in shipping horses,” continued Kohn. “The first two chapters of the book summarize the risk factors and offer those guidelines. The last chapters substantiate what we offer in the first chapters.

“It’s information useful to anyone, whether they are hauling five miles down the road or overseas, or whether they are veterinarians, researchers, or the horse-owning public.”

This research can’t be done overnight; some questions might take years to find answers. Other research might define new standards in a short time.

“We can build a better mousetrap,” said Kohn of the boxes and containers used to ship horses. “We can only give opinions now based on past research and experience, but research can give us the answers. But once we get one answer, it leads to six different questions.”

Funding will be critical to finding answers, and the group from the initial meeting–who came from all over the world–hope to collaborate and therefore more quickly reach solutions to transport problems.

Kent Allen, DVM, who not only works on a daily basis in his referral practice for top equine competitors but has served as the head of veterinary services at the Atlanta Olympics, said, “The main thing about this book is that it is the first coordinated effort in addressing this problem with competition horses that will fly and drive quite a bit in a career. It’s one of the first opportunities to recognize and ad-dress these issues and make sure these athletes don’t suffer in transport.”

Calling it Transport 101, Allen said the book demonstrated that information for horse owners and vets can be brought together.

“I learned a tremendous amount just being associated with the seminar and reading the manuscript,” said Allen. “It’s changed what I tell my clients on how they prepare horses for transport, transport them, and what they do after transporting them.”

Those clients include champion husband-wife team David and Karen O’Connor.

Allen, who with Kohn spearheaded the heat and humidity studies that allowed the equestrian events at the Atlanta Games to be called the most uneventful as far as health issues goes, said the next step with transport is more research.

“It’s just like the heat and humidity problems, we need to go back to the basics,” he said. “We need to go to Transport 102.”

Horse owners or other interested parties can contribute to the success of this research by donations made through the AHSA or Federation Equestre Internationale (FEI) and designated for transport research.

“The AHSA this year funded four projects for $10,000 each on horse health. Some are travel-related, and some are not,” commented Allen. “We need to help these researchers studying transportation make headway.”

Transport Studies

In one section, it is explained that while “stress” is tough to define and study, there are parameters of health and illness that can be measured to determine how a horse is reacting to a certain situation. The authors state: “Road transport has been reported to induce a number of behavioral, physiological, and pathological responses in horses. These responses include decreased body mass, reduced food intake, behavioral changes during and after transport, elevations in heart rate and energy expenditure, increased concentrations of plasma cortisol and adrenocorticototropic hormone (ACTH), serum biochemical changes, increased progesterone concentrations and embryonic death in pregnant mares, fluid and electrolyte imbalances, diarrhea, reactivation of Salmonella infection, azoturia and/or rhabdomyolysis (tying-up), and pulmonary infections commonly known as ‘shipping fever.'”

It was postulated that transport-related stress likely is due to many factors, including confinement, movement, noise, lack of previous experience traveling, the presence of exhaust or other gases, changes in air temperature, humidity, and airborne microorganisms. These, the researchers said, basically fall into four broad categories.

1) Environmental–factors such as temperature, humidity, season, day length/time of day, and ambient air quality (dust, air pollutants);

2) Vehicle design–factors that are related to the characteristics of the transport vehicle, such as ventilation (effects of window and vent placement), recirculation of interior gases, insulation and noise (sound intensity and quality), visual cues, suspension and its effect on vibration, and accelerations and decelerations.

3) Management during transport–factors such as frequency and duration of stops, feeding and water, method by which horses are restrained in the vehicle (head height, direction), and skill of the driver.

4) Biological responses–the physiological responses of individual horses to the above stressors, potentially influenced by such factors as sex, age, prior shipping experience, socialization with surrounding horses, reproductive status, vaccination status, and prior or subsequent exposure to potential path-ogens and/or non-transport stressors.


Unpublished data from Japanese research showed that heart rates and accelerations were significantly and positively correlated. Respiratory rates increased during transport, yet decreased to nearly pre-transport values while at a stop. These results suggest that vibration and oscillation (movement) during transport have the potential to act as a stressor. Japanese research also studied different magnitudes and frequencies of oscillation in a large (18-horse) transport van. They measured movement forward and backward, right and left, and up and down. It was discovered that frequency of maximum movements of the van was lower for expressways than for other roads. It also was discovered that the magnitudes of acceleration along all three of the measured parameters exceeded the limits of allowable values for vehicle vibration in humans.

Interior Environment

Horses contaminate their environments when they are transported, and they must live with those conditions until a stop or the trip is over. Also, there are a large number of airborne microorganisms present in the transport vehicle. One study noted that retention of gases in an enclosed two-horse trailer can be modified by altering the flow of air into and out of the trailer, particularly by opening and closing the doors at the rear of the trailer. The research noted that minimal changes in interior air flow pattern and washout resulted from opening and closing of windows and vents.

Because of this contaminated environment, it is important that horses be able to clear their respiratory passages. To do this, a horse must lower its head and either cough or blow out through its nose. Head posture of a horse in a trailer usually is restricted by having the head tied in an upright, fairly static position. Most transports don’t allow a horse to have its head loose. Studies have shown that horses confined with their heads elevated for 24 hours developed an accumulation of purulent airway secretions, increased numbers of bacteria in the lower respiratory tract, and decreased tracheal mu-cociliary clearance when compared to horses allowed to lower their heads.

There is anecdotal evidence that suggests that rear-facing horses in transport vehicles might be more relaxed than those facing forward. While one researcher reported no difference in heart rates from horses facing forward or backward during transport, other research has shown elevated heart rates when horses face forward. They also found that most horses–but not all–placed in a transport vehicle without tethering preferred to face backward when the vehicle was in motion, but not when it was parked.

In another unpublished study from Japan, the influence of road transportation on cellular immune function was studied. To evaluate this, 29 Thoroughbreds (3-year-olds) had blood drawn immediately before and after being shipped 1,676 km over 38 hours. During the journey, 12 of 29 (41%) developed a fever. There were changes in parameters used to measure immune function, indicating stress on the horses’ immune systems. Another study that transported horses for 12 hours found that these cellular immune function parameters were evident for at least 36 hours following transportation. This suggests that horses require a number of days to recover normal immune response after the stress of transportation.

Another study showed that exercise performances of racehorses in daily training and with road transport experience were not adversely affected by transport of less than three hours duration. Effects of road transport of longer duration on performance and the physiological response to exercise have not been assessed.

Shipping Fever

It has been discovered that while an “overly inclusive term,” shipping fever usually is caused by one of three distinct etiologic agents–strangles, influenza, and contagious pneumonia. Study results have indicated that incidence of respiratory disease increases with transport distance and/or traveling time. In one Japanese study (unpublished), 37 horses (3-year-olds) were shipped 1,708-1,858 km for durations of 36-41 hours. The incidence of horses developing fever (pyrexia) at the conclusion of the trip was 13.5%. However, the incidence of horses developing fevers during or after the trip was 43.2%. This finding supports the hypothesis that transport time is positively correlated with the incidence of transport-associated disease. The research also showed that no horses experienced pyrexia until after approximately 12 hours of transport, and the incidence increased dramatically after 18-20 hours of transport.

This suggests that reducing travel time to less than 12 hours should greatly reduce the probability of a horse experiencing transport-related pyrexia and/or respiratory disease.

Other research has shown that the classic clinical signs of shipping fever might largely be caused by the development of pneumonic lesions during road transport. These might be associated with opportunistic infection by resident bacteria.

Study Needed

Areas for future study were defined as the following:

1) To determine the biological effects of vibration and jolting on horses with and without previous transport experience. Additionally, to determine what frequencies of vibration of oscillation are associated with deleterious biological effects in horses. These findings could be used to develop road transport vehicles with vibration characteristics that produce minimal adverse effects in horses.

2) To clarify the causes and mechanisms of lower respiratory tract bacterial contamination associated with road transport. Particularly important is to clarify the effect of head posture on airway clearance of contaminants or native bacteria.

3) To clarify the relationships between length of journey (travel time) and post-transport recovery period, particularly with respect to determining the interval of re-covery required between transport episodes to minimize the incidence of transport-associated respiratory disease.

4) To develop an easily identifiable and rapid diagnostic test for transport-associated respiratory disease, especially subclinical cases that are not readily recognized.

In summary, the transportation book offers this statement: “There is substantial evidence that both the quantity (time) and quality (environmental and management factors) of the transport experience play a role in eliciting transport-associated disease in horses. Many horses travel regularly with few detectable adverse effects, so it is clearly possible for some horses to adapt to the demands of transport while remaining disease-free. The multitude of factors that potentially contribute to the development of transport-associated disease suggests that, in many cases, it should be possible to identify and modify factors in the transport environment to reduce the stress, insult, or impairment of function that leads to disease

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Written by:

Kimberly S. Brown is the editor of EquiManagement/EquiManagement.com and the group publisher of the Equine Health Network at Equine Network LLC.

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