The new HBO series, Luck, was a month into shooting its second season when it was abruptly cancelled after three horses died on set since the filming of the first season began.

The horse-racing show, starring Dustin Hoffman, Dennis Farina, Joan Allen and Nick Nolte, had been criticized by PETA since the 2010-11 filming, when two thoroughbreds were euthanized after being hurt during racing scenes.

The third horse was recently being led back to its stable when it "reared up, fell backward and was injured," according to TV Line. A representative for the American Humane Association who was on set overseeing the production called the resulting injury "untreatable," reports Cleveland.com.

"It is with heartbreak that executive producers David Milch and Michael Mann together with HBO have decided to cease all future production on the series," said the network. "While we maintained the highest safety standards possible, accidents unfortunately happen and it is impossible to guarantee they won't in the future. Accordingly, we have reached this difficult decision."

PETA supports the cancellation, and advises that the production use stock footage of horse racing should it choose to resume in the future. The American Humane Association called the cancellation "the best decision HBO could have made."

HBO added that it was "immensely proud" of Luck and "loved the series, loved the cast, crew and writers." The network will continue to air the remaining episodes of this season, but will not return for Season Two.

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