Horse racing has long withstood the deaths of its skittish, injury-prone thoroughbreds. Hollywood proved it lacks the stomach for it.
HBO abruptly canceled its racetrack drama series ''Luck'' this past week after three horses used in the production were injured and euthanized during 10 months of filming in the past two years.
The abrupt fall of ''Luck,'' which will end its single-season run on March 25, reveals the chasm between the racing and entertainment industries.
At the track, a horse puts its life on the line so gamblers can stake $2 or more to win, place or show, with the industry and fans accepting the danger to animals and jockeys as a harsh part of the bargain.
With movies and TV, which offer the on-screen vow that ''no animals were harmed'' in the making of make-believe, consumers have scant tolerance for harm to any creature great or small.
''More people are pet owners than ever before. More people have access to information about animals . . . and care more about them,'' said Karen Rosas, senior vice president of the American Humane Association's TV and film unit that monitors animal safety for more than 2,000 productions annually.
During the past five years, the association encountered only one horse death outside of ''Luck,'' on the 2007 movie ''3:10 to Yuma,'' Rosas said. Losing three horses on a single project was ''unprecedented,'' she added.
The racing world stands in sharp contrast in both the measure of loss and reaction to it.
Two horses died in Britain's Grand National steeplechase meet last year, and four the year before, but the April event will proceed as it has since the 1830s. The 2008 Kentucky Derby euthanasia of a captivating filly, Eight Belles, clouded but didn't derail the event that marks its 137th running in May.
Last week, five horses died in the first two days of the United Kingdom's Cheltenham Festival steeplechase meet. Outrage erupted, as it had after previous multiple deaths in the prestigious meet, but it's yet to be scuttled.
In US racing, there's approximately one horse fatality per 500 starts, according to Dr. Rick Arthur, medical director of the California Horse Racing Board. He cited the Equine Industry Database posted online by The Jockey Club, which supports thoroughbred breeding and racing.
''Luck'' filmed some 2,500 racing sequences, most a few slow, staged furlongs rather than all-out contests, Arthur said, citing estimated figures from HBO.
Two thoroughbreds were put down after suffering fractures while running. The third was euthanized for a head injury suffered when the horse slipped and toppled backward, an accident experts said isn't uncommon for the fragile, high-strung animals that weigh about 1,200 pounds.
The losses provoked public dismay, along with pro and con debate about racing itself.
''I am usually an admirer of both HBO and (series creator) David Milch, but from the sounds of it, this is a tragedy that should have been avoided. Animals are not props,'' actor Sean Vincent Biggins of Los Angeles posted Friday on his Facebook page.
Thoroughbred experts and those in racing say their acceptance of mortality in racing stems from an understanding of the animals powering the sport.
''You don't force a racehorse to race. They love running,'' said Dr. Larry Bramlage of Lexington, Ky., a nationally prominent equine veterinarian with 37 years' experience. ''If you came to where I am right now, with all the yearlings in the field, you'd see them out there trying to prove who runs the best.''
Richard Mandella — a Hall of Fame trainer at Santa Anita Park, the sprawling, historic track in the Los Angeles suburb of Arcadia where ''Luck'' was filmed — said ''a love affair'' exists between the people and horses in racing.
But even hard work and ''extreme efforts'' can't protect the animals, he said.
''As far as accidents happening . . . I don't care if they're in a prairie or anywhere, that can happen,'' Mandella said. ''They play rough, and they're competitive.''
What happened to the HBO show, he suggested, could have been a run of sad misfortune.
''Luck'' was the kind of high-profile project that the premium TV channel bases its reputation on, with industry heavyweights in front of and behind the camera.
The drama about the underbelly of racing starred Dustin Hoffman, in his first TV series, as a crime boss scheming to bring casino gambling to a track. Nick Nolte, Joan Allen, Michael Gambon and Dennis Farina were among other high-profile actors in the show.
Series creator and producer Milch has had success in broadcast TV with ''NYPD Blue'' and on HBO with ''Deadwood.'' Michael Mann, the big-screen director whose credits include ''Heat'' and ''Public Enemies,'' paired with Milch as producer and directed the pilot.
The complex drama proved a challenge for viewers, and ''Luck'' fell far short of an HBO hit such as ''The Sopranos,'' drawing as few as 500,000 for a weekly debut showing. But the combined figure that included DVR viewings was 4.8 million per episode, exceeding that of other HBO shows including ''Treme,'' ''Enlightened'' and ''Bored to Death.''
Milch, a successful race horse owner himself, had generated a misfire for the channel before, with the short-lived ''John from Cincinnati'' in 2007, but he is a valuable creative partner for HBO. Making the decision to end production on ''Luck'' was a difficult but, it seems, inevitable one.
HBO, owned by Time Warner Inc., was being hit by the kind of bad publicity that only the most successful project could justify enduring.
Among those condemning the equine deaths was People for the Ethical Treatment of Animals, which called oversight of the animals' welfare inadequate and alleged that old, unfit horses were being overworked.
Those claims were rebutted by HBO, Dr. Arthur and the humane association's Rosas, who said the group's guidelines are much more stringent than any federal, state or local regulations.
''Racing itself is dangerous enough. This is a fictional representation of something and horses are still dying, and that to me is outrageous,'' Kathy Guillermo, a PETA vice president, said after the second equine death.
Famed racing industry members voiced regret over the cancellation, although there had previously been mutterings from some about how ''Luck'' depicted the sport's seedier side.
''It's very disappointing. I was hoping it'd be a big hit. I feel bad for all the people they employed,'' Bob Baffert, Hall of Fame trainer and three-time Kentucky Derby winner, said in Santa Anita's daily stable briefing last week.
Marc Bekoff — a University of Colorado professor emeritus of evolutionary biology and author of ''The Emotional Lives of Animals,'' about animals in entertainment — reserves his sympathy for the horses.
Bekoff, who wants to see computer-generated imagery and other tricks used in place of filming with live animals, took a combined slap at racing and Hollywood.
''Horse racing in general suffers from a lot of questionable ethics,'' Bekoff said. ''Running staged encounters with these horses raises the same questions.''
