Simone Biles’ Dog Breeder Claims He's Getting Death Threats For Ear Cropping Pup

Simone Biles' dog breeder is receiving a ton of backlash for cropping her new Doberman Pinscher's ears and docking its tail ... telling TMZ Sports he's gotten death threats over something he says is "common practice."

We spoke with the owner of Regal Empire Dobermans after fans and PETA slammed Biles and her husband, Jonathan Owens, for buying a puppy that underwent the procedures.

William Regal is also dealing with the blowback ... telling us people have made seriously menacing comments toward him, and have attempted to have his company shut down.

"This is a procedure done by licensed veterinarians in the U.S.," Regal said. "It's common practice."

Regal also explained the reasoning behind the adjustment ... stating a Doberman's long tail can break and cause significant pain. He added ear cropping is done to prevent medical issues like hematoma, and it can reduce the risk of injury if attacked by other dogs.

Regal -- who's been in the breeding business for 10 years -- said he doesn't want to beef with PETA or critics of the practice .... but feels the threats against him and the disrespect shown toward the Olympic legend and NFL player have gone too far.

He added that Biles simply wanted a dog for protection.