Los Angeles ? 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 last two years.

The abrupt fall of “Luck,” which will end its single-season run 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.

In U.S. 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.