LEXINGTON, Ky. — A sport that loses three athletes a day is undertaking new steps toward beefing up safety, the result of disasters that claimed the lives of two of its top competitors.

The sport is horse racing, and the deaths of 2006 Kentucky Derby winner Barbaro followed by the euthanization of filly Eight Belles last May on the track at Churchill Downs have sparked an array of safety initiatives. What’s unclear is how much they’ll help.

Among the changes in place for the Derby this Saturday are padded starting gates, replacement of welt-inducing whips with noisy but less painful riding crops, a ban on a type of cleated shoe believed to cause injuries and laws against anabolic steroid use in almost every racing state.

Alex Waldrop, president of the National Thoroughbred Racing Association, said the sport’s response discredits the argument of some that horse racing can’t adequately police itself the way pro football or baseball do because it lacks a central authority.

“What were our supposed ills? That we were 38 fiefdoms that could never get together, never agree on anything?” Waldrop said. “Well, we’ve demonstrated that we can change.”

Yet not everybody is convinced the changes are sufficient — or ever can be under the current structure.

U.S. Rep. Ed Whitfield says he plans to introduce legislation as early as this summer that would compel racing states to comply with safety standards or risk losing the massive simulcasting revenues granted to them by Congress under the Interstate Horse Racing Act.

“There’s been cosmetic changes — more committees formed,” the Kentucky Republican said. “They’re looking into this and that and making improvements, but the bottom line is, not a lot of change.”

Unlike their human counterparts, broken limbs don’t just sideline an equine athlete from competition but often end careers and even lives.

Horses are biologically built to stand and run on all four thin legs, so extended bed rest can disrupt the flow of blood to the wounded limb and cause severe arthritis and infection. Because Eight Belles had two broken legs, saving her was out of the question, and she was euthanized immediately. Barbaro broke down at the 2006 Preakness Stakes and underwent extensive medical treatment before finally being euthanized on Jan. 29, 2007.

Just on Monday, a 2-year-old filly died at Churchill Downs in Louisville following a collision with another horse. Raspberry Miss sustained multiple fractures in her pelvis when Doctor Rap dumped its jockey and ran into her during training. No Derby hopeful was involved, but several were on the track at the time.

The Associated Press found last June that thoroughbred racetracks in the United States reported more than three horse deaths a day in 2007 and at least 5,000 in a five-year span beginning in 2003. Several states indicated they don’t even monitor the deaths, and many others don’t count morning training accidents or race-related injuries that lead to horses being euthanized after they depart the racetrack grounds.

Veterinarian Mary Scollay is working to compile a comprehensive database of thoroughbred injuries in hopes of drawing some conclusions about what causes them.

After releasing initial findings that indicated virtually no difference in the fatality rate between dirt tracks such at the one at Churchill Downs and a cushiony synthetic surface heralded as safer, Scollay backtracked, explaining the sample size was small. She relaunched the study in November with 75 tracks representing 81 percent of all live racing starts in the United States and pledged to wait a year before analyzing the data she’s collecting.

While most tracks are now participating in Scollay’s study by submitting detailed information about each horse that gets hurt and the track conditions that day, a few remain holdouts.

One of the largest is Oaklawn in Hot Springs, Ark. David Longinotti, the track’s assistant general manager for racing, said racing officials there don’t monitor fatalities, in part because many horses don’t die until they are hauled off to equine hospitals. The nearest of those is in Oklahoma, several hours away, he said.

“Whether we participate or not, I don’t think is going to move the needle one way or the other,” Longinotti said. “We’ve got one of the safest racetracks in America.”

Indeed, Oaklawn was one of the first to install a safety rail around the track and to regularly check the consistency of the racing surface. Now those efforts and many others, such as the padded gates and bans on certain whips and shoes, have become industry standards under a new accreditation process for thoroughbred racetracks.

Churchill Downs was the first track to get the Safety Alliance’s stamp of approval earlier this month, followed soon after by Keeneland in Lexington. Both tracks were praised for far surpassing the minimum requirements, submitting their racing surfaces to daily testing with a robotic device that simulates the movement of a horse’s hoof to detect any bad spots on the track.

“We’re not going to just give this an eyewash,” said Tommy Thompson, a former Wisconsin governor and Health and Human Services secretary who was hired to be an independent monitor for the accreditation process. “We’re going to really give this an in-depth inspection. I wouldn’t be part of it if it was just going to be a public relations gimmick.”

Yet there are some calls to go further, especially at a time when racing deaths are not the only high-profile problem.

Big Brown’s victories in the Derby and Preakness last year were tarnished by revelations that he was given steroids, albeit then legal at the time, which led to bans in 25 states. And, while an entirely separate matter, the deaths of 21 prized ponies during a championship polo match have led to questions about drug use in equestrian sports.

Some have suggested the thoroughbred breed is getting weaker through matings designed to produce speed rather than stamina, and that the emphasis in the sport should be shifted to give more purse money to races involving older horses.

Meanwhile, science is starting to show some promise in the area of injury detection. Wayne McIlwraith, a professor at Colorado State University, has been researching biomarkers in bone scans that he says can prove which horses are at risk for a fracture, even before they race.

All of the developments could reduce the risk to the animals. But Larry Jones, who trained Eight Belles, said nothing can be done to eliminate accidents from the sport.

“Unless they want to start swimming these horses, start having swimming races, you’re still going to have horses take bad steps, and injuries are going to happen,” he said. “Some of that is just being an athlete.”