Monday, May 7, 2012

Monday Medical Issues: Microchipping

Since May is Microchip Your Pet Month, we thought it would be a good topic for a Monday Medical Issues post.

Microchipping is growing in popularity, with an increasing number of animal shelters offering it as a free service to all animals upon adoption.

But what are the statistics surrounding microchipping?

What are the risks? What are the benefits? And - most important - do the benefits outweigh the risks?

photo: Adobe Veterinary Center
Microchipping your pet involves embedding a rice-sized pellet between your dog or cat's shoulder blades just below the back of the neck. (On other animals the location may vary, and in Continental Europe, the practice is to locate the microchip in the left side of the neck).

No anesthesia is required, though I have to admit, I requested it be done while Faraday was anesthetized during his teeth cleaning after I saw Allie cry out when she was injected - those needles are just a teensy bit bigger than standard!

This pellet contains a tracking number that is maintained in a database. That database contains owner information and, depending on the database, can also contain veterinarian info and even medical records.

When an animal is found, one of the first things a veterinarian or animal shelter does is to scan the animal for a microchip.

Microchip Myths, Facts
and Scientific Stuff

One of the stories circulating around microchips is that they cause cancer. That fear may be related to the fact that some vaccination injection sites have proven to cause cancer in some animals, particularly cats. (this will be the topic of a future Monday Medical Issues post). Here's what the research tells us: the British Small Animal Veterinary Association (BSAVA) maintains a database on the adverse reactions of microchips on animals. At the time the study was posted, only 391 animals out of 4 million were reported experiencing an adverse reaction. That's 0.00010%, or 1 out of every 10,000 animals microchipped.

And the majority of those issues involved the migration of the microchip, not cancer. Two of those cases recorded were dogs who had developed cancer at the site, but one of them, according to the BSAVA study, may have been caused by something else.

In comparison, you're about 4 times more likely to die in an auto accident than your pet is to have any kind of adverse reaction at all, and 4 times more likely to be struck by lightning than your pet is to get cancer from a microchip.

As a result, the American Veterinary Medical Association has deemed microchipping to be worth the risk. 

Picture Source: ainhoap and Animal Photos!
Why? Let's talk about the benefits for a few minutes. 

A study of almost 8,000 stray animals at animal shelters concluded that dogs who were not microchipped were only reunited with their owners about 22% of the time.

Dogs who were microchipped were reunited over 52% of the time. 

That more than doubled your pup's chance of finding you should you become separated. 

And the odds for cats exponentially increase. A non-chipped cat has less than a 2% chance of being reunited with his owner. But microchipped cats went back to their families almost 40% of the time.

We're all for increasing the odds of any lost pet being rehomed, so we give microchips four paws up.

Next week:  

The science behind how microchips work 
and other reasons for microchipping you 
might not have considered

sources:  Lord, et al, "Journal of American Veterinary Medicine Association", July 15, 2009 


  1. I have seriously considered microchipping my pets but I was told that there is no one database that contain all the necessary information to unite a lost pet with it's family (in our country). Instead, the information is stored by the vet who administered the microchip. So, when a lost pet is found, all they can do is say, yes, there's a microchip with this number. And that's it. Kind of defeats the purpose, doesn't it?

    1. Sure does!!

      We're lucky in the U.S. to have the AAHA (American Animal Hospital Association) Universal Microchip Lookup Tool, a database that contains information from 4 of the 6 companies that manufacture them: AKC CAR, HomeAgain, Petlink by Datamars and resQ by Bayer.

      Hopefully this will become increasingly universal, and more companies worldwide will participate in database sharing.

  2. I always thought there WAS a master database with microchipping information. There isn't for tattooing, though. At least not in Canada. My brother Seville was tattooed but the peep phoned every single vet for 100 miles in both directions and not a single one recognized the tattoo. When Seville went in for his first doctor's appointment, my doctor checked for a microchip. She seemed to think that THAT she could track down. No microchip though. But no worries... I got a new brother and he came all neutered and everything.

  3. This is very interesting information and I'm so happy you are sharing it. I was microchipped atg the anipal shelter before M & D could bring me home, so I'm all set. M went the extra mile and also got a collar with an ID tag on it just for good measure - even tho I"m an indoor cat mostly.

  4. In the US, there are 2 major microchip companies - and the number indicates which company owns the chip. The biggest problem we have seen - the animal has a chip - and the owner DIDN'T register it. Defeats the purpose. Everyone here (except Maestro) has a chip. And most of us wear collars with tags and our chip tags on them. When Tommy got out of the house almost 2 years ago, mom had some peace of mind knowing he has a chip and it is registered to us....

    1. That's our biggest beef with them too!!!

      And that's why we chose ResQ by Bayer. The microchip comes with a no-fee, lifetime registration. AVID, the microchip we use at our shelter, does not. It costs the adopter $20 to activate plus $6 each time you change your information (if you move, etc) - and our concern is that many people don't. Often we'll get a cat returned to us (picked up by animal control) that is microchipped - we scan it and find the number - but there is no owner info. TOTALLY defeats the purpose!!!

  5. Our chips are all woefully out of date/ not registered and all that bad stuff - my human needs to get on the ball!

  6. All my boys are microchipped even though they are strictly indoor cats in case the unthinkable happened and somehow somebody got outside by accident. Jimmy is a very petite cat and I think the microchip needle hurt him because he cried out and struggled while they were inserting it. This of course upset me but I still believe that chipping is very important!

  7. Harley and I are microchipped. My Mommeh knows if we ever got out, we'd probably never be able to find our way home again. We just have to remember to keep the contact info updated.

  8. The peeps got me microchipped even though I'm an indoor cat. Grandpa was actually struck by lightning. HAH!

  9. Austin is chipped. I believe that in the UK there is a central database, but change of ownership doesn't always make it onto the database!

  10. We're all microchipped even though we're indoor cats. You never know when someone's gonna sneak out a door! Plus, since I go in the stroller, it was especially impawtant I be chipped, otherwise, Mom would probably not open the stroller to pet me or give me treats while we're out. And I'd never get to walk around outside ever! Not even on a leash. Mom's just a little overprotective.


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