In the UK, recent legislation regarding the microchipping of dogs means that all dogs over 8 weeks of age must be micro-chipped or their owners may face a fine. Similar laws are already in place in other parts of the world, and in some countries cats are also included.
Whether cats should be included in legislation to make microchipping compulsory is controversial, as cats hold a very different legal status to dogs under UK law. However, International Cat Care strongly advocates the voluntary microchipping of all cats as studies have shown that cats with a microchip are 21 times more likely to be reunited with their owners than non-microchipped cats if they become lost (Dingman et al, 2014).
The accurate and permanent identification of pet cats is therefore both important and desirable. While collars with tags can be useful to identify cats and carry contact information, these are not ideal as they can sometimes be broken, become separated from the cat and if not designed well can also cause injury. Microchipping is the best method of permanent identification.
Why microchip?
Microchipping involves inserting a tiny implant under the cat's skin (usually the scruff of the neck). This electronically encodes a unique number that is linked to a central database containing the owner's address and telephone number. Should the cat become lost or separated from its owner, a microchip scanner can be used to identify the cat and find the owner. Veterinary clinics and homing centres routinely use these scanners to identify stray cats and reunite them with their owners. Having a microchip may also be important in other circumstances — for example:
- In the sad circumstance that a cat is run over, its owner can be informed and not left wondering where the cat is
- In legal cases when a cat's ownership is questioned
- When veterinarians are submitting test samples to a laboratory from a breeding cat for possible inherited diseases.
Can inserting a microchip harm the cat?
International Cat Care is in agreement with the World Small Animal Veterinary Association (WSAVA, 2017) and the American Veterinary Medical Association (AVMA, 2017) in affirming that microchipping of dogs and cats is safe and very rarely associated with any significant problems. The microchip is the size of a grain of rice and is implanted in a similar way to giving a vaccination, causing very minimal, temporary discomfort. Implantation of a microchip generally results in some mild transient inflammation at the site of implantation, which is followed by development of a fibrous capsule around the microchip which usually helps to ensure it stays at the site it is implanted (Linder et al, 2009; Gerber et al, 2012). The microchip is then linked to a central database (e.g. the National PetLog Database) that holds all the details of the pet and the owner.
While the procedure should cause little or no discomfort, it is important that only a veterinary surgeon or other properly trained individual administers the microchip as incorrect placement can have severe consequences. Significant complications from the appropriate implantation of microchips in cats appear to be exceptionally rare. Data reviewed by the WSAVA suggest microchips are a safe and effective means of identifying pets. They also state that, of the many millions of animals that have been microchipped, only a tiny proportion have had any type of problem reported. The most common problems reported are simply related to movement of the chip under the skin which may make scanning for the chip a little more difficult or, less commonly, failure of the chip.
Microchip implantation sites for canines and felines
The use of standard microchip implantation sites reduces the risk of failure to detect an implanted microchip (Fry,1999). In the canine and feline, there are two currently recognised implantation sites in use:
- The microchip is implanted subcutaneous on the dorsal midline just cranial to the shoulder blades or scapula. This is the standard implantation site in all countries (including the UK and the Republic of Ireland) excluding those of Europe
- The microchip is implanted subcutaneously in the midway region of the left neck. This is the standard implantation site in continental Europe (excluding the UK and the Republic of Ireland).
Until one common global site can be agreed on, it is imperative that scanning concentrate on the implantation site commonly used in that geographic locale. Should an animal scan negative, it is strongly recommended that the alternative site in use, as defined above, also be scanned.
Some recorded complications of inappropriate microchip placement
- Forceful implantation of a microchip in a 2-year-old cat by its owner resulted in microchip placement in the spinal canal causing tetraparesis and tachypnea. The microchip was surgically removed and 11 months after the surgery the cat was able to weight bear in all limbs, but with mild residual paresis in the left thoracic limb (Platt et al, 2007).
- In two separate case reports, inappropriate microchip implantation into the spinal canal of small-breed puppies resulted in acute-onset tetraparesis that gradually resolved following surgical removal of the microchip (Hicks and Bagley, 2008; Smith and Fitzpatrick, 2009)
- An alpaca is reported to have died following inappropriate implantation of a microchip into its spinal canal (van der Burgt and Dowle, 2007).
When should cats be microchipped?
Many owners have their cats microchipped at the same time as vaccination or when they are under anaesthetic for neutering. A cat can benefit from being microchipped at any age, allowing easy identification and tracking of the owner, but wherever possible it is best to have kittens microchipped (often done at 3–4 months of age) to provide them with protection throughout their life.
Are the details up to date?
It can be very frustrating for those dealing with lost or stray cats to find that owners cannot be contacted because they have moved away and not informed the microchip company of their new contact details. In a study of stray dogs across the UK, the database contact details were out of date more than half of those that had microchips, emphasising the importance of keeping this information up to date (Batter-sea Dogs & Cats home, 2016).
If the cat is microchipped, check with the owner that the microchip company has the correct details for it (veterinary nurses can explain to clients how to do this), and advise clients to always make sure this information is updated if they move.
Conclusion
There really is no reason not to have a cat microchipped, and it can mean the difference between a cat being lost permanently or being reunited with its owners.