Horse Breeding for Speed Getting Down to a Science

Even before Smarty Jones reaches the starting gate at today’s Belmont Stakes, trying to become horse racing’s first Triple Crown winner since 1978, the race to breed another champion in his image has begun.

In Reddick, Fla., I’ll Get Along -- the mare who foaled Smarty in 2001 -- is carrying a full sibling of the Kentucky Derby and Preakness Stakes winner, due next March. Two months into an 11-month gestation, the fetus is the size of a mouse, with tiny, developing hoofs.

In Versailles, Ky., Smarty’s sire, Elusive Quality, is led to the breeding shed at Gainsborough Farm two to three times a day, seven days a week, to fulfill dates with 135 mares this season at $50,000 each -- a fee that will go up next season. After his work in Kentucky is done, the stallion will be shipped to Australia for the Southern Hemisphere breeding season, where 85 mares await.

The mating of thoroughbreds in quest of victory at the track has long been a sophisticated combination of art and informal science. Owners and breeders study thoroughbreds’ family trees so closely, they are more likely to be able to list a horse’s great-great-great grandparents than their own.

Yet the ways genes recombine generation after generation are so unpredictable, the axiom long has been, “Breed the best to the best and hope for the best.”

Now, as 100 scientists at 25 laboratories around the world cooperate to map the horse genome for the first time, geneticists and a few figures in the traditional world of thoroughbred breeding are beginning to explore the ways genetic information might enhance the chances of breeding a champion.

“Everybody is trying to get a faster racehorse,” said John Adger, the bloodstock expert at Stonerside Stable, a breeding operation and racing stable near Paris, Ky., owned by Robert McNair, who also owns the Houston Texans of the National Football League. “People have been trying to do it for centuries, but again, you didn’t have the mapping of the genes like you do now.”

Unlike the completed map of the human genome, the equine gene map is a work in progress.

But with the advice of McNair’s friend and business partner Dr. C. Thomas Caskey -- a renowned human geneticist and former president of the Merck Genome Research Institute and the Human Genome Organization -- Stonerside has begun a project with Texas A&M; University in which researchers will study the DNA of thoroughbreds in search of genetic clues to their success on the racetrack.

“We are trying to find markers that may help us -- and there’s no guarantee -- to differentiate between winners and non-winners. I don’t want to use the word losers,” said Bhanu Chowdhary, a professor of animal genomics at Texas A&M.;

A British company, Thoroughbred Genetics Co., already has been advising clients on breeding and purchases for several years by using DNA analysis in addition to traditional breeding theories, though many scientists question whether enough is known about the horse genome yet to perform a marker-based selection.

Still, Steve Harrison, the company’s managing director, is eagerly awaiting results as colts produced by matings he recommended begin racing in the next two years.

None of the scientists seeking answers to the centuries-old puzzle of how to breed a faster horse is proposing cloning or manipulation of the genes. They simply want to use DNA analysis as a tool to make more effective decisions about which stallions and mares to breed to one another.

Even if someone wanted to clone a Triple Crown winner, the Jockey Club, which governs the registration of thoroughbred foals, already had banned clones even before Italian scientists produced the world’s first cloned horse in 2003.

The Jockey Club also prohibits embryo transfer or any form of genetic manipulation and -- in what seems an old-fashioned notion in light of advances in human fertility -- still requires the “physical mounting of a broodmare by a stallion.”

Yet the ways in which traits are handed down are so complex, even a full sibling of a champion racehorse is no sure thing to succeed on the racetrack. Secretariat had a full sister, the Bride, who never won a race.

“As somebody said, Larry Bird probably has a brother who can’t play basketball,” said Geoffrey Russell, director of sales at Keeneland, the race course near Lexington, Ky., where the most prestigious yearlings are auctioned at two annual sales.

(Bird has four brothers, and none ever played an NBA game.)

“The interesting question is: What is the nature of racing?” said Ernie Bailey, a geneticist at the University of Kentucky’s Gluck Equine Research Center and a coordinator of the international genome effort. “People come visit our lab and we tell them about genes that control immune response, disease resistance, all these elegant experiments.

“They sit patiently and listen, and then they raise their hands and ask, ‘Have you found the speed gene yet?’

“Racing performance is much more complex. Speed probably is not a matter of one gene, but different genes combining in different ways. That’s the thing that makes racing a fascinating sport.”

Matthew Binns, a geneticist with the Animal Health Trust in Newmarket, England, is another of the researchers hoping to find markers that signal the likelihood of success on the racetrack.

“What do we mean by racing performance?” Binns said. “Instinctively you know it means winning the big races, but that involves the heart, lung, bones, muscles and temperament. Each is complicated genetically.”

Heart size is seen by many as a particularly important factor.

An autopsy of Secretariat -- 1973 Triple Crown winner and a great-great-grandfather of Smarty Jones -- revealed a heart almost twice the size of the typical thoroughbred’s.

Yet what makes a winner also is more than physiology: There is the issue of environment, and factors such as training, illness, injury, the skill of the jockey, even a horse’s competitive spirit.

“I think it’s kind of an indecipherable quality they’re trying to get to,” said Brent Fernung, the general manager at Cloverleaf Farms II in Reddick, Fla., where Smarty Jones’ dam is in foal with his sibling.

“They’ve done so much with cattle genetics and weight gain and fat percentage. That’s something that’s easily measured. Racing ability is a little different. You can’t look inside that as easily.”

Ultimately, a number of scientists believe, the contribution of genetic study to racing might not be discovering what makes a horse such as Smarty Jones go fast, but what could keep him from doing it.

“Whether we’ll ever find a ‘go-fast’ gene, I doubt it,” said Jim Murray, professor of animal science and veterinary medicine at UC Davis. “The genome project ultimately will help ... as we understand more and more about horses -- more about bone development and why they go lame, for example.”

In fact, one of the major benefits of the horse genome project so far has been the development of tests for three important diseases that affect certain breeds: an immunodeficiency syndrome known as SCID that affects Arabians; a muscle disease in quarter horses known as hyperkalemic periodic paralysis, or HYPP; and a disease affecting spotted horses called lethal white syndrome.

Developing tests for genetic problems in thoroughbreds eventually could improve performance.

“You could say, ‘What things limit racehorses?’ ” said Binns, the British researcher. “Having fractures of their bones, bleeding in the lungs. Nearly all the main problems would be caused partly by genetics and partly by environment.”

Each year, some 36,000 thoroughbred foals are registered in North America by the Jockey Club. Only one will win the Kentucky Derby. Only 11 have ever won all three races of the Triple Crown, a feat Smarty Jones will attempt to complete today in Elmont, N.Y.

Those are considerable odds.

Add to that the fact that a horse has about 30,000 genes, arranged on 64 chromosomes.

“It’s going to be very hard to predict the outcome of a mating,” said Douglas Antczak, director of the James A. Baker Institute for Animal Health at Cornell. “It’s a mind-staggering amount of different combinations.”

The equine lotto paid off unexpectedly for Roy and Patricia Chapman, a couple well along in years who had never had even a starter in the Derby until they bred their champion at a place in Pennsylvania they called Someday Farm.

It will be next year before the racing world gets a look at Smarty’s first full sibling, and even longer before it is clear whether the foal can race.

All the while, scientists will be working to improve the odds in a business sometimes seen as a crapshoot.

“I hope they never get too good at it,” said Cloverleaf manager Fernung. “If they do, the richest people will have the best horses. Then you wouldn’t have great stories like the Chapmans.”