LOUISVILLE, Ky. — The filly Eight Belles finished second behind favorite Big Brown in the Kentucky Derby today, then collapsed with two broken front ankles and was euthanized after crossing the wire.

The field of 20 horses was galloping out around the first turn at Churchill Downs when Eight Belles suddenly went down on both front legs and jockey Gabriel Saez slid off.

"When we passed the wire I stood up," said Saez, a first-time Derby rider. "She started galloping funny. I tried to pull her up. That's when she went down."

An equine ambulance reached her near the second turn and tended to the filly.

"There was no possible way to save her," on-call veterinarian Dr. Larry Bramlage said. "She broke both front ankles. That's a bad injury."

Trainer Larry Jones and owner Rick Porter decided to run Eight Belles against the boys in America's greatest race despite her never having done so before. She brought in solid credentials with a four-race winning streak and then ran gallantly.

The dark gray filly also was entered in Friday's Kentucky Oaks for fillies. Jones, however, won that race with Proud Spell and set himself up to pull off the double.

Eight Belles was the first filly since 1999 to run in the Derby; the last to win was Winning Colors in 1988. She didn't press 2-1 favorite Big Brown down the stretch, and he drew away to a 4¾-length victory.

Still, Eight Belles was a sentimental pick by 157,770 fans, second-largest crowd in Derby history. She even had the support of Democratic presidential candidate Hilary Clinton. Eight Belles repaid their faith by returning $10.60 and $6.40.

Jockey Kent Desormeaux and Big Brown galloped by Eight Belles in her waning moments.

"This horse showed you his heart and Eight Belles showed you her life for our enjoyment today," he said. "I'm deeply sympathetic to that team for their loss."

At first, Jones didn't realize anything was wrong until he began walking back to the stable area and saw Saez aboard another horse.

"There was no way to save her," a visibly upset Jones said. "She couldn't stand."

Bramlage said the fracture in Eight Belles' left front ankle opened the skin, allowing contamination to set in. At least one of her sesamoid bones was broken, too.

"She didn't have a front leg to stand on to be splinted and hauled off in the ambulance, so she was immediately euthanized," he said. "In my years in racing, I have never seen this happen at the end of the race or during the race."

Eight Belles appeared to be galloping out normally around the first turn and was headed into the start of the backstretch when she dropped without warning. The crowd was busy high-fiving and celebrating and because of the distance from the grandstand, many didn't realize tragedy had struck.

"Everyone breathed a big sigh of relief that everyone came around the track cleanly and then all of a sudden it happened," Bramlage said.

"Horses really tire. They are taking a lot of load on their skeleton because their muscles are fatigued. The difficult thing to explain with her is it's so far after the wire, and she was easing down like you'd like to see a horse slow down by that point. I don't have an explanation for it."