Horse Backs Hurt by Riders, Saddles
By Jennifer Viegas, Discovery News
April 18, 2006 - Horses in the wild never carry anything on their backs, and now a new study has found that when a horse bears the weight of a rider, it adjusts the position of its back and alters its limb movements, all of which could contribute to back pain and injury.
The determination adds to a growing body of evidence that horses used for recreational or sporting purposes are at risk for health problems associated with these activities. Many scientists, such as Patricia de Cocq, who led the recent study, hope the findings will improve conditions for horses in future.
"The goal of this study is to advise horse trainers and saddle fitters on how to prevent injuries," said de Cocq, who is a researcher in the Experimental Zoology Group at Wageningen University in the Netherlands.
For the study, de Cocq placed special infrared light reflective markers on horses that were on treadmills. Infrared cameras used the reflected light to generate 3-D images that focused on horse back vertebrae, joints and limbs as the animals walked with and without loads. The maximum total weight was approximately 165 pounds.
She found that while all weight caused a horse to adjust its back position, the saddle with a rider led to the greatest adjustment.
"During walk, trot and canter, the position of the (horse's) back is more extended in the situation with a saddle and weight," de Cocq told Discovery News. "Although the back is more extended during the complete stride cycle, total movement - expressed as range of motion - stays the same."
The findings were presented at the Society for Experimental Biology's annual meeting in England earlier this month.
The back extension, according to de Cocq, is consistent with probable causes for the condition of "kissing spines," when loads and repeated undulations push parts of the horse's back close together.
This usually happens between the withers and the loin, or in the region that involves the 10th-18th vertebrae. In advanced cases, sometimes parts of the spine even grow together.
"It is thought that the process is only painful in (this) acute phase," she said.
Probably because of uneven weight distribution, horses with longer backs are more likely to suffer from back problems associated with riding. It is possible that horses bred to bear heavy loads, such as Icelandic horses, may be less vulnerable, but de Cocq said she has not studied these horses yet.
Back problems are not the only risk to horses that carry human riders. A recent Journal of the American Veterinary Medical Association study found that some racehorses experience hemorrhaging from the pulmonary artery into the bronchial tubes and windpipe during intense exercise.
The disorder was most commonly found in horses that lost races and trailed the winner by an average of 14 feet.
Half of all thoroughbreds experience this problem, called exercise- induced pulmonary hemorrhage, according to lead author Kenneth Hinchcliff, who is a professor of veterinary clinical sciences at Ohio State University.
He said a number of treatments, including drugs and herbal products, are often administered before racing, but it is not clear if they always work.
For horse riders, de Cocq offered this advice: "Riders should pay attention to the signals a horse can give.
For example, 'cold back' (when a horse stiffens its back or negatively reacts after bearing weight), problems with saddling, girthing and mounting the horse may be an indication that there are problems with the saddle or the riding technique."