Judy Cochran (left) took one shot to kill the 580-pound ’gator: Scott Hughes

A great-grandmother has shot and killed a 12ft alligator at her ranch in Texas after blaming it for eating her beloved miniature horse.

Judy Cochran used a high-powered rifle to slaughter the 580lb reptile at a pond on her property in the rural town of Goodrich.

Her son-in-law caught it using a seasoned raccoon as bait, and called to let her know the huge animal had been hooked.

Ms Cochran, called “Nana” by her grandchildren, then killed it with a single bullet.

“Don’t mess with Nana,” she said.

The great-grandmother told The Houston Chronicle: “We think this is the ’gator that ate one of our miniature horses several years ago.”

Ms Cochran, who is the newly elected mayor of the nearby town of Livingston, insisted all parts of the hunt had been done legally.

“There are a lot of requirements to kill a ’gator in Polk County,” she explained. “We’re one of 12 counties that has a hunting season for alligators, between September 10 and 30. You have to have a permit and tags from a wildlife biologist, and you have to catch it on a hook first.”

She now plans to make boots from the alligator’s belly and have the head mounted after the animal was taken to a local taxidermist.

“We’ll eat the meat, have the head mounted and have the ridgeback part of the tail in my office,” the mayor said. “We’ll have the hide tanned to make some boots out of it – you can only make boots from the belly.”

After posting the photo of the hunted alligator on Facebook, Ms Cochran told Fox News affiliate KDFW-TV that some of her friends did not initially believe she had killed the alligator.

“Several people wrote back saying, ‘No you did not do that.’ I said, ‘Yes I did do that.’”

Ms Cochran’s grandson Simon killed an alligator at the same pond back in 2009, when he was just five years old.

“My friends were proud of me, and I was proud of myself,” the boy said at the time.