LITTLETON, Colo. -- If a cat has nine lives, how many lives does a dog have?

Thanks to some generous donors at the canine blood bank at Animal ER in Littleton, some dogs have more than one.

Louie, Littleton Mayor Doug Clark's German shepherd, is one of them.

"He got very sick just before New Year's," Clark said.

Clark said he got Louie as a puppy from a passerby who wanted to give him up.

"He was on his way to the pound and he said, 'I see you have a German shepherd, do you want another one?' We said yes, and he's turned out to be a super dog," Clark said.

Late last year that super dog suffered a twisted stomach. Clark took him to Animal ER, where vets operated on him and gave him two units of blood.

"Being able to save any animal is the best feeling in the world," said Dr. Ann Eliopulos, a veterinarian at the after-hours clinic.

Elioipulos said Animal ER instituted its blood bank in 2000. A bulletin board in the lobby shows the photos of all the donors.

"I'm incredibly grateful to the people who donate blood, who bring animals down here to give blood transfusions so that animals like Louie can live," Clark said.

Lizz Landert is one of those people. Her black Labrador, Marnie, has been a regular donor.

"She's been doing it for almost 5 years now," Landert said. "And when they turn 7 they can't do it anymore, so this is her last blood draw."

The last draw was old hat for the friendly Lab. Staff members hoisted Marnie onto the exam table, shaved her neck, then inserted the needle.

"She responds to everybody. She loves people," Landert said.

When asked why she got Marnie involved in giving blood, Landert said that her lab was originally trained to be a guide dog. She said she wanted Marnie to continue to help others.

"It was just something that she could do," Landert added. "She's very calm, easy to handle, and I thought it was a worthwhile thing to do for other dogs. She may need it someday."

That's the attitude that Rick and Carolyn Lontin have adopted. They say having their great Dane, Ninja, donate blood was always in the back of their mind.

"We had an older dog who had cancer and we thought it would be nice for Ninja to do because she was a big dog and she was healthy," Carolyn Lontin said.

But it was only after Oswald, their rottweiller got sick and needed a transfusion that they sprang into action. They brought Ninja along to donate blood.

"It was great. (Oswald) wouldn't be with us if it weren't for this program and these people," Rick Lontin said.

Eliopulos, known affectionately as "Dr. E," said the blood bank offers incentives to owners whose dogs donate blood. Among them: free blood work, heart worm testing and heart worm treatment.

"There's a small stipend," the doctor added. "Many of our owners are so great they donate the stipend back to our stray animal fund."

The folks at Animal ER are so appreciative of their donors that they throw a small party for them every year. But it's the owners whose dogs get the transfusions that are most grateful.

"It means a lot," Clark said. "Because without them, Louie wouldn't be alive today."

If you're interested in having your dog donate, contact Animal ER at 720-283-9348. Only dogs in good health between one and seven years old can donate blood.