Track personnel try to hold down Eight Belles after the 134th Kentucky Derby. Eight Belles was euthanized Saturday after breaking both front ankles following a second-place finish in Louisville, Ky.

Louisville, Ky. ? Brianne Cima kept bobbing up and down, she was so eager to cash her $5 ticket on Eight Belles.

An equine science student from St. Louis, she’d come to the Kentucky Derby to back her favorite filly with a button and a bet.

“That’s my girl!” she said Saturday, waiting at the wagering window a full 45 minutes after the race.

Then, someone told her the heartbreaking news: Eight Belles broke down after finishing second and was euthanized on the track.

Cima went silent. A tear ran down from her left eye, and she dabbed it, smearing her makeup.

“Excuse me, I’m sorry, I’m crying,” she said. “I can’t believe it.”

Neither could most of the 157,770 fans. Word spread slowly and unevenly through the stands, by cell phones and word of mouth.

There was no official announcement made over the loudspeakers. Many people still didn’t know while the last two races of the day were run at Churchill Downs.

It was an all-too-familiar scene for the sport.

Barbaro buckled at the Preakness in 2006 and was put down eight months later. A colt collapsed on the Derby track Friday and stands only a 50-50 chance of surviving.

“Losing animals like this isn’t fun,” Eight Belles trainer Larry Jones said, choking up between sentences. “It’s just the unfortunate side.”

Eight Belles became the first horse to be euthanized at a Triple Crown race since Prairie Bayou at the 1993 Belmont. A few weeks earlier, Union City was destroyed at the Preakness.

A spokesman for Churchill Downs said it was not known whether Eight Belles was the first horse to die on the track at the Kentucky Derby.

Jones, too, needed awhile to figure out what happened about a quarter-mile past the finish line, after Big Brown won the race – Eight Belles broke both her front ankles and couldn’t be saved.

“I was very pleased she hit the wire running,” Jones said. “I saw her ears were up, she was watching Big Brown.”

“When she ran second, we were ecstatic,” he said. “We were kind of high-fiving.”

Only when he saw Big Brown jockey Kent Desormeaux ride past did Jones realize something was wrong.

“You could tell it’s not like he had just won the Kentucky Derby. He was a little bit solemn,” Jones said.

Moments later, he heard a horse had broken down.

“I figured it was one of the ones who had run poorly,” Jones said.

Then, he heard it was his horse, took off running for the ambulance and rode to Eight Belles.

The bones were protruding through the skin, a catastrophic injury that left no alternative.

“When I saw it, it had to be done,” he said.

The whole afternoon, Eight Belles had been a crowd favorite.

All over the track concourse, vendors sold $1 buttons to benefit the Permanently Disabled Jockey Fund. There were plenty left for Visionaire, Cool Coal Man and even Big Brown – the ones for Eight Belles sold out early.