Eight-year-old Rottweiler Eric is recovering well after ground-breaking stem cell surgery for his arthritis.

But it will be several weeks before it is known whether the $4500 treatment has cured the arthritis in his front legs.

"He's sleeping it off. It's like he's got a big hangover," owner Christine Smithies said. "It's like he's had a big night out."

Eric underwent the three-hour stem cell surgery at Pet Doctors, Henderson, Auckland, on Monday.

The treatment is relatively new in New Zealand.

It involved cutting tissue from Eric's abdomen, separating out the cells and then injecting them into his affected joints.

Vet David McCormick was pleased at how it went, but said it would take some time to see results.

"One week out, we're probably not going to see much improvement. More commonly, most of the improvement is seen at the three- or four-week mark."

He said the fat tissue was surgically removed from the abdomen and processed to extract the stem cells.

After X-rays were taken to identify the afflicted areas, the stem cells were injected into Eric's left shoulder, left and right elbow, left and right wrist joint and left foot. There, they would have an anti-inflammatory and regenerative effect.

"These cells will be starting to secrete some anti-inflammatory hormones called cytokines. It's basically having a targeted anti-inflammatory effect on a specific area," said McCormick.

"We do know the whole thing behind stem cells is they, given time, have the ability to grow new bone and cartilage cells."

Eric is the sixth dog treated by McCormick.