DAVIS, Calif. -- Organ transplants can be life-saving procedures -- not just for humans, but also for pets.

The University of California-Davis Veterinary Hospital is one of only a handful of animal hospitals in the country that perform pet kidney transplants. It began animal kidney transplants in 1987. It is one of the first clinical programs in the country and is regarded as one of the best.

But the procedure hasn't come without controversy, reported KCRA-TV in Sacramento, Calif.

"We didn't offer to start kidney transplantation. We were asked by the public to start kidney transplantation," said hospital spokeswoman Dr. Clare Gregory.

To Jonathan Pick, his cat, Maxwell, is more than just a pet.

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Cat Transplants Surrounded By Controversy

"He is a member of our family," Pick said.

Maxwell became a candidate for a kidney transplant at the UC Davis Veterinary Teaching Hospital. The cat was suffering kidney failure, and taking another cat's kidney was his last chance.

The procedure is expensive. The deposit alone is $6,000. It's also risky. Organ rejection and even death are not uncommon.

"Twenty percent don't make it past the first year," said Dr. Margo Mehl, a surgeon at the hospital.

Pick decided to go ahead with surgery, choosing a donor from the research cats in the nutrition lab. Adopting the donor, Frodo, will be part of the deal. People come in with one cat, but leave with two.

Pet kidney transplants are surrounded by controversy. Animal rights groups say it's a violation of the donor animal because its organs are taken without its permission.

"These cats don't give their consent to have their kidneys removed, nor have they given consent to be research subjects at UC Davis," said Michelle Thew a spokeswoman for the Animals Protection Institute.

On surgery day, Maxwell and Frodo were put under anesthesia. The operation takes hours and requires a team of doctors. It's meticulous work. The needle is smaller than an eyelash, and the thread is thinner than a hair.

"I think his outlook is good," Mehl said after the surgery.

Two weeks after surgery, Maxwell and Frodo were sent home. Maxwell will have to take antirejection drugs indefinitely, but his recovery is going well.

"We're starting to see the Maxwell that we used to see. Every day, he gets a little bit better," Pick said.

The hospital says it does kidney transplants for cats on a regular basis but rarely does transplants for dogs because canines are genetically more diverse and not as well-suited for transplant surgery.