If you need lungs, a kidney or even a heart, you can be put on a transplant list, and becoming an organ donor is often as simple as checking a box at the DMV.
However, donating and receiving life-saving organs is a little more complicated for cats and dogs.
While pets often receive bone, soft tissue and cornea allografts for transplantation, the only type of organ transplant available for cats and dogs is a kidney transplant, according to Dr. Lillian Aronson of the University of Pennsylvania's School of Veterinary Medicine, who talked to Vetstreet.
The reason is because any other organ transplant would kill the donor and, unlike with humans, there's no infrastructure or nationwide network in place in the event of sudden pet death.
However, that could be changing.
Donating pet organs
Kansas City, Kansas, is home to relatively new Pet Organ Donation Network, which was established to protect research animals and to provide organs to dogs and cats in need.
The program is the first of its kind, and it connects veterinarians, researchers and pet owners in the Kansas City metro area.
Just like with human donors, when organs can't be used for transplantation, they're sent to research laboratories. Currently, organs used in research are taken from animals raised in labs.
The organs in the Pet Organ Donation Network are often obtained from euthanized animals, and participating pet owners say there's comfort in knowing something positive can come from saying goodbye to a beloved cat or dog.
There's currently no system in place to track donor organs, but the network's website says it hopes to someday connect donors with recipient animals.
How a kidney transplant works
While most organ transplants aren't possible for our four-legged friends, kidney transplants are fairly common, but finding donors can be difficult.
Both dogs and cats can receive a donated kidney, but the procedure is mostly performed on cats because donors and recipients don't have to be related. Only a blood test is required to make sure the felines are a match.
It's more difficult to suppress a dog's immune system, so dogs are more likely to reject a donor kidney unless it comes from a related dog, which can be difficult to find.
Still, just because kidney transplants are easier in cats doesn't make the issue any less complicated.
Kidney donors can be either a cat in the same household or a shelter cat that the owner agrees to adopt after the transplant. Even though the donor cat will live, it's a murky ethical area for some.
"In other countries, such as England, no one would ever consider doing a kidney transplant in pets. Why should you take the kidney out of a healthy pet?" Richard Walshaw, professor of small animal surgery at Michigan State University's College of Veterinary Medicine, told DogChannel.
A donor cat must be young — but at least 1 year old — and healthy, and the recipient must be in good health other than its kidney failure.
Transplants can be pricey, often costing more than $20,000 for surgery, post-operative care, medications and checkups. Once the transplant is complete, the donor will spend a few days in the hospital while the recipient may spend a few a weeks under veterinary care.
After a successful transplant, a recipient will live an average of two to three years — alongside a new companion, if the donor comes from a shelter.
"The owner of the recipient is responsible for adopting the donor cat, so we're saving two cats' lives," Aronson told Vetstreet.
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