Executive Producers David Milch and Michael Mann, in conjunction with television network HBO, have released a statement that they are halting all future production of horseracing drama Luck after a third horse had to be put down on Tuesday over an injury sustained on the set of the show.

Tuesday morning a mare reared up on its hind legs and fell backwards, breaking its neck in the process, and had to be euthanized due to the severity of the injury. The tragedy is the third of its kind after two more horses had to be put down during filming of the first season of the show in 2011.

"Safety is always of paramount concern," the statement reads. "We maintained the highest safety standards throughout production, higher in fact than any protocols existing in horseracing anywhere with many fewer incidents than occur in racing or than befall horses normally in barns at night or pastures. 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.

"We are immensely proud of this series, the writing, the acting, the filmmaking, the celebration of the culture of horses, and everyone involved in its creation."

People for the Ethical Treatment of Animals (PETA) officials called on HBO to cease filming on Tuesday, calling the deaths of all three horses a "sloppy oversight" and accusing the series of using "unfit or injured horses."

Producers of the show refuted PETA's accusations, saying, "Recent assertions of lax attitudes or negligence could not be further from the truth.

"We partnered early on with the American Humane Association, which is the only mandated authority in the industry, and we work very closely with the AHA and racing industry experts to implement safety protocols that go above and beyond typical film and TV industry standards and practices."

Earlier today producers had planned to stop production of all equine scenes until the Humane Society could investigate the deaths properly, but ultimately decided to cancel production outright.