Bred for Speed ... Built for Trouble

Much as we try, we can't stop humanizing our horses. This one's got the heart of a champion; that one has the guts of a mudder. We don't really know if there's anything behind all that anthropomorphizing. But we do know that a horse can suffer as we do--feeling pain, fear, confusion and shock. All of that was on display at Pimlico Race Course in Baltimore, Md., when Kentucky Derby winner Barbaro shattered his right rear leg at the Preakness Stakes just moments out of the gate. It was the most stunning racehorse disaster since the death of the famous filly Ruffian in 1975 and perhaps the most gruesome sports injury to any creature since the nationally televised sight of Washington Redskins quarterback Joe Theismann's leg snapping like a bread stick in 1985. But there's something about a Thoroughbred coming undone--something about that exquisite engine of muscle, bone and congenial will crashing down--that moves us. In the days since Barbaro's accident and surgery, the horse--now housed in a 13-ft. by 11-ft. stall at the University of Pennsylvania's George D. Widener Hospital for Large Animals--has received a flood of cards he can't read, endless baskets of fruit he won't finish, and flowers he may or may not smell. Tens of thousands of dollars and untold hours of effort will be spent on his care, all for an animal that--his potential $30 million in breeding fees notwithstanding--was already insured up to his velvety ears.

But we love our horses--so much that we may be wearing them out. Racehorses sustain lethal injuries an average of 1.5 times in every 1,000 starts, according to some studies. A millennium after the sport was born, we're breeding horses to finer and finer tolerances, racing them earlier and harder and producing an animal that may be a thrill to watch but is increasingly hard to keep whole.

"The market wants a faster, earlier-maturing horse," says Dan Rosenberg, president of Three Chimneys horse-breeding farm in Midway, Ky., "but there is an incompatibility between speed and durability." Not everyone in the industry agrees, but injuries like Barbaro's raise the question anew every time they occur.

Horses are undeniably born to run, a survival strategy that befits a prairie herbivore with neither fangs nor claws. While a lot of animals are fleet of foot, horses achieve their speed more elegantly than most, starting with their disproportionately long legs. Limb length usually means bulk, since it takes a lot of muscle to move long bones. But muscles add weight, and weight reduces speed. The horse solves that problem by packing its musculature in its upper body, then transferring that power down to the legs with an elaborate rope work of tendons and ligaments that absorb shock as the animal runs and then snap the leg back to reuse the energy on the next stride. The system works well, but it does leave the legs exceedingly vulnerable to injury because when a break occurs, the blood vessels embedded in the limbs can torque and tear.

Ingenious as the horse's overall design is, humans couldn't resist tinkering with it. About 300 years ago, breeders began crossing fleet European mares with strong Arabian stallions, producing a faster animal that could run longer distances. All Thoroughbreds today are descended from just three Arabian males--the so-called foundation sires.