He has not been back since.  “We’ll go to the Derby when we’ve got the horses,” said Simon Crisford, the manager of the Maktoum family’s Godolphin Stable, which is based in Dubai and has sent horses to victories in many of the most prestigious races around the globe.  There is little doubt that the sheik is spending a great deal of money to return to Churchill Downs. He has been the leading buyer at Keeneland’s September yearling sales over the past eight years, spending $245.6 million. The sheik has also built a commercial breeding and racing business on more than 4,000 acres in the bluegrass of Kentucky.  James Tafel can match the sheik’s passion for finding a Kentucky Derby winner, but not his bankroll. Nearly 25 years ago, Tafel retired as the chairman and chief executive of a publishing company near Chicago and began racing, and then breeding, horses.  “You know the appeal of the Kentucky Derby is pretty spectacular and straightforward,” said Tafel, who is 83 and lives in Boynton Beach, Fla. “It’s the aspiration of all horsemen to have a horse in the race. It’s our gold standard. I make the case it’s the greatest race in the world, because if you’re on a plane or waiting in line, and you tell someone you’re in the horse business, the only question they have is, ‘Have you won the Kentucky Derby?’ ”  Now, the two men are linked. On Saturday, Tafel will be in the paddock at Churchill Downs for the Derby with Street Sense, a colt who was the 2-year-old champion last year and will be among the favorites. His sire, Street Cry, is owned by Sheik Mohammed, as is the colt’s mother, Bedazzle, who was purchased last year by the sheik’s breeding operation, Darley America.  The sheik may not have a horse running in the Derby, but his impact on American thoroughbred racing is being felt. Another one of the sheik’s Kentucky-based sires, Cherokee Run, is the father of the Derby starter Zanjero. If Street Sense or Zanjero wins, Darley America will be able to command bigger breeding paydays for years to come.  The value of Street Cry, for example, has increased largely because of the accomplishments of Street Sense, who won last year’s Breeders’ Cup Juvenile. When Tafel matched Bedazzle with the recently retired Street Cry, he was gambling a $30,000 stud fee on a new sire. Now, Street Cry stands for $50,000, a figure that will most likely double if Street Sense wins the Derby.  Last fall, the sheik acknowledged that he had made a mistake by buying too many horses with pedigrees better suited to the turf racing in Europe than the dirt in America. Tafel says he understands how Sheik Mohammed has repositioned his operation for a more effective Kentucky Derby run. He has done so, too, but on a much smaller scale. Tafel culled his broodmares to 6 from 12; the sheik has more than 160 in Kentucky.  “You get into the racing side of the game, and you end up with some nice fillies or mares, and their value is greater as breeding stock,” said Tafel, who has had one other Derby horse, Vicar, who finished 18th in 1999. “So you back into the breeding game, and it sustains the racing operation in lean times.”  The making of Street Sense is perhaps further evidence that beating the long odds of getting a horse to the Derby has more to do with luck than with money or strategy.  In 2002, Tafel watched as his horse Unshaded, who had won the 2000 Travers Stakes, was trounced by an impressive-looking horse in the Stephen Foster Handicap at Churchill Downs. It was Street Cry.  “I remembered what a great back end he had and how much balance,” Tafel said. “It just stuck with me.”  When he showed Carl Nafzger, his trainer of 23 years, Street Sense, both men were impressed. Here was a perfectly proportioned weanling he had produced in the fields of Kentucky. When the offers to buy the yearling began coming in, they knew they had a reason to be impressed.  “Well, he was about as perfect a specimen as you’ve seen, as a weanling, as a yearling to now,” Nafzger said. “You couldn’t buy one that looked this good all the way through.”  Tafel has refused to hear any offers for the horse, especially from the sheik, who last year offered $17 million to Elizabeth Valando, the owner of Nobiz Like Shobiz, after the colt won a maiden race. Valando turned it down, and Nobiz will be among the Derby favorites on Saturday.  In 2005, Tafel sold Bedazzle to a group led by Nafzger for $180,000 at the Keeneland November breeding stock sale. Last fall, after Street Sense ran off to a record 10-length victory in the Breeders’ Cup Juvenile, Nafzger sold the mare to Darley America for an undisclosed price.  Tafel says he has no regrets. In Street Sense, win or lose, he has a valuable stallion prospect. A victory Saturday, however, would increase the colt’s value to as much as $30 million. But that is not what Tafel or, he suspects, Sheik Mohammed views as the point of racing and breeding.  “It’s the Kentucky Derby,” Tafel said. “And just thinking about walking a horse over there as good as this one is more excitement than a guy my age should be able to have.”  A version of this article appears in print on , on Page D1 of the New York edition with the headline: Bloodlines Worth Their Weight In Gold. Order Reprints| Today's Paper|Subscribe
Like no other horseman in the world, Sheik Mohammed bin Rashid al-Maktoum has learned that it is easier to build the world’s tallest building than it is to win a Kentucky Derby.