by: Pat Raia
April 01 2009, Article # 13880
Our horses' lifestyles, career demands, and the way we manage them can cause more stress than we might expect.
Sue McDonnell, PhD, Certified Applied Animal Behaviorist, was preparing a horse for long-distance transport. Getting the horse from her home base at the University of Pennsylvania's New Bolton Center to his final destination involved a jostling trailer ride to the airport, then a cross-country flight. Compound that with separation from his stablemates, a disruption of his normal feeding schedule, and having to adapt to his new environment, and the horse was under considerable stress.
"Every time we put a horse on a trailer, I'm amazed at how well they do and how much we expect from them," said McDonnell, who is the founding head of the Equine Behavior Program at the University of Pennsylvania School of Veterinary Medicine. The horse on the move is exposed to nearly every factor recognized as a potential stressor for horses. Each one has the potential to make him vulnerable to a myriad of physical ailments, from respiratory infections to gastric ulcers.
But horses needn't be in extreme circumstances such as long distance travel to experience stress. Extreme hot and cold climate conditions, training regimens, dietary or feeding schedule variations, general daily routine disruptions, injuries, and changes in social interactions with other horses and humans can all represent equine stressors.
According to Carey Williams, PhD, equine management specialist and assistant director of the Equine Science Center at Rutgers University, horses' very nature makes them particularly sensitive to stressful situations. As prey animals, horses are genetically hard-wired with a "fight or flight" response nervous system that physio- logically allows them to turn on a dime in the presence of danger--either real or perceived. Under stress, a horse's endocrine glands flood his body with adrenaline and cortisol--the so-called "stress hormone" also present in humans--and his heart rate increases. While all that is happening on the inside, horses outwardly display a stressful state by swishing their tails, pawing the ground, bucking, kicking, biting, or fleeing the troubling factor altogether.
Evolution equipped horses with their fight or flight responses to keep them safe from predators or other threats in the wild. These days it's the realities of domestic life that stress horses.
According to Williams, studies show that 80-90% of all racehorses, 60% of all performance horses (including eventers, jumpers, and Western performance horses), and 30-40% of dressage horses develop gastric ulcers during the normal course of their careers.