Kathy Willens, Associated Press
Big Brown is walked back to his barn by groom Herasmo Gonzalez, right, and exercise rider Michelle Nevin after Saturday's Belmont.

ELMONT, N.Y. — In Barn 12 on Sunday morning, Nick Zito accepted congratulations for spoiling yet another Triple Crown bid. Just as he did in 2004, Zito stopped the coronation of a Triple Crown champion. Four years ago, he did it with the 36-1 shot Birdstone against Smarty Jones. This time, it was a 38-1 longshot named Da' Tara beating Big Brown.

What happened Saturday in the 140th running of the Belmont Stakes, however, was far more shocking, and perhaps sad.

Big Brown was considered such a stone-cold lock to become the 12th Triple Crown champion that industry honchos had already printed invitations for a celebration to fete the colt on Monday at Tavern on the Green.

In Barn 2, Big Brown's temporary home at Belmont Park, there was no one around Sunday morning to explain how the big bay not only got beat but also had to pull up under his jockey, Kent Desormeaux, and surrender before running even two-thirds of the mile-and-a-half race. Big Brown's trainer, Rick Dutrow, was nowhere to be found, nor were any of his owners.

Big Brown seemed fine as he walked the barn with his regular exercise rider, Michelle Nevin; the diagnosis, as well as prognosis, remained the same as it did late Saturday night. He had been examined, scoped, poked and prodded by veterinarians.

"Nothing, nothing and nothing," Michael Iavarone, a co-president of International Equine Acquisitions Holdings, which owns part of Big Brown, said later in the day by telephone. "He scoped clean. His feet are ice-cold. The quarter crack is not an issue. We're perplexed. No one can figure this out. We're watching him closely and hope we didn't miss anything."

As usual, the second-guessing was rampant. Did Desormeaux wrangle him too hard early, taking the run out of Big Brown? Were the three days of missed training because of the quarter crack and Dutrow's careful training schedule responsible for an out-of-shape horse? Could it have been the weather?

Worst of all for Big Brown's connections, perhaps, were the questions about steroids. Dutrow told The New York Times last week that Big Brown had not had his usual shot of the anabolic steroid Winstrol since April 15, enough time for the drug to leave his system.

Was Big Brown's poor performance because of his lack of "juice"?

"He wasn't on steroids for the Preakness," Iavarone said. "There is a million things that could have got him beat. If people are going to say that no Winstrol got him beat, they are going to say that."

Zito made it clear that the questions about steroids and other drugs in horse racing had put a damper on his second Belmont triumph and fifth Triple Crown victory overall in what is a Hall of Fame career.

"The lords of horse racing need to get together and make some rules that we all abide by," Zito said. "It's a big issue, and we can't ignore it, and we need to get past it."

Before the race, Zito declined to say if his two horses in the Belmont, including Anak Nakal, who dead heated for third, would be on steroids. He declined Sunday as well to say if his horses had received steroids. In the wake of Eight Belles' fatal accident after finishing second in the Kentucky Derby, and Dutrow's frank discussion of pharmaceuticals over the course of the Triple Crown, there appears to be a groundswell of support in the industry to ban steroids and prohibit race-day medications.

Besides losing the Triple Crown and a place among immortal horses, Big Brown's poor performance in the Belmont diminished his reputation as a racehorse and may have significantly decreased his value as a stallion, not to mention his marketing value. Before the Preakness, Three Chimneys Farm in Midway, Ky., purchased a percentage of Big Brown's stallion rights in a deal valued at $60 million.

If he had become the first to sweep the series since Affirmed did so in 1978, Big Brown was expected to stand for at least $200,000 a mating and, as the only living Triple Crown champion, be worth up to $120 million.

Instead, IEAH and Big Brown's other co-owners are going to be hard-pressed to restore the stallion market for the colt to perhaps half of that $60 million level. Big Brown does not hail from a particularly fashionable pedigree: His sire, Boundary, stood for $10,000 for 11 seasons before being pensioned, and he produced a modest 16 stakes winners, mostly sprinters.

Big Brown is pointed next to run in the Travers at Saratoga in August, and the Breeders' Cup Classic in October at Santa Anita, where he is likely to meet Curlin, reigning Horse of the Year.

"It puts a little more pressure on us to win those races," Iavarone acknowledged. "I know a lot of people say we haven't beaten anyone, and we needed to take on older horses."

So for now, Big Brown's future is pretty straightforward. Dutrow, Iavarone and his camp will go back to the drawing board.

Unless a physical ailment shows up, Iavarone says the colt will maintain his regular training schedule in Dutrow's main barn at Aqueduct and perhaps breeze as soon as two weeks from now.

"All we can do is chalk this up as a mystery," Iavarone said, "and regroup."