Passive Transponder System (microchip) in veterinary practice
Dr.A.V.Belsare, B.V.Sc &A.H
B-3, 26, Sarita Vaibhav, S.No 119/2, (Part) Parvati, Pune 411 030
anyadoc@gmail.com
Veterinarians are well aware of the need for individual animal identification and its role in effective herd management, tracking/proving ownership, regulatory requirements (CITES), zoo animal management and certain wildlife interventions (IUCN guidelines). Some countries have regulations for importing animals and animals have to be microchipped before importing. This is to ensure that the animal and the vaccination record belong together. Older methods for individual animal identification like branding, tattooing and ear tagging are being replaced by this new technology, Passive Transponder System.
A passive integrated transponder (PIT tag) or RFID (radio-frequency identification) chip or microchip is a small (~size of a rice grain: 2.2 x 12 mm), unobtrusive, inexpensive, biocompatible device, which is given a unique alphanumeric code at the time of manufacture (e.g. 00063B3F95). The animal injectable microchips are supplied in individually packed sterilized needles and are injected with a specially designed injector. With a microchip reader (or scanner), the code on the microchip can be interrogated. The reader activates the transponder electro-magnetically, which then sends the code to the reader. The decoder in the reader processes the code and displays it on the LCD. There are many companies manufacturing microchips and scanners, and a scanner manufactured by one company might not read a microchip manufactured by other company. There is no universal reader, though a multichip reader is available. One has to ensure that appropriate microchip reader(s) are available so that the commonly used/ encountered chips can be read. Settings have to be changed in a multi reader to scan chips of other companies.
The microchip cannot be tampered with and is a permanent, unalterable system that provides a unique code to every animal, thus the risk of fraudulent activities is minimized. Once implanted, the microchip will last throughout the animal's lifetime. A microchip typically lasts at least 25 years.
In most species, with the exception of avian and some reptile species, the transponder microchip is implanted subcutaneously. The actual procedure is as simple as a subcutaneous injection or vaccination and does not require any anesthesia. I normally do this procedure in pups at the time of first vaccination (6 weeks) and most of the pups don't react at all.
No site preparation is necessary, not even rubbing with alcohol swab. Alcohol does nothing to make the skin cleaner; and the needle and the transponder come in a sterilized package.
As a first step, I strongly recommend scanning the animal to ensure that it has not been already microchipped (especially imported dogs) and avoid unnecessary repetition. Scanning should begin at the recommended implantation site and if no chip is detected the alternative site should also be scanned. For example, the global implantation site for dogs is subcutaneously at the base of neck, on the dorsal midline, between the shoulder blades. An alternative site is subcutaneous, midway on the left side of the neck.
The scanner should be held very close to the animal, actually gliding it in contact with the skin or fur. The trigger button has to be held in pressed position throughout each pass. As per the manufacturers guidelines, the following technique should insure 100% data capture:
Make four passes longitudinally from the mid neck to over the shoulders, two on each side of the neck. Make four passes transversely in the same area covering a dorsal arc of 90 degrees.
The scanning should be done for a minimum of 10 seconds and on two consecutive occasions before declaring an animal negative for the presence of a microchip.
Implanting microchip
a) Scan the unopened needle with microchip and write down the alphanumeric code.
b) In case of TROVAN microchips, place the needle assembly on the injector/implanter and lock the implanter. The DESTRON (ISO) microchips come in a ready to use disposable injector.
c) Implantation is just like giving a subcutaneous injection. Remove the needle cap, in a steady motion penetrate the skin and pull the skin fold back over the length of the needle. Unlock the implanter and depress the plunger. Never depress the plunger before the needle is inserted into the animal, otherwise the microchip will be ejected.
d) Withdraw the needle and then let the skin go.
e) Scan the site with the reader to ensure proper placement of the microchip and crosscheck with the written code.
Ensure that the microchip is inserted in the connective tissue below the skin. As the needle is of a large gauge, appropriate care must be taken to prevent injuries. Slight bleeding at the point of injection is not unusual and has to be dealt with in the usual way.
Implanted microchips should be scanned periodically, at least once a year, to ensure proper functioning and to confirm location. Though the newer microchips have antimigrating properties, faulty placement might result in the microchip migrating from the original site of implantation.
At present, TROVAN- ID 100 microchips and TROVAN microchip reader (hand held reader LID 500 and pocket reader LID 571) are available in India with Helpro Health Products & Services (helpro@ sancharnet.in).
ISO chips (DESTRON Technologies) are also available with some breeders.
In India, we need to ensure the following:
1) Standardization of microchip implantation site for various species.
2) Agree on the brands of microchips to be used in animals.
3) Availability of the appropriate scanners at rescue centers, shelters, municipal dog pounds, etc.
4) Setting up a regional and national database, which can be accessed by veterinarians, animal shelters, kennel clubs, etc.
Apart from microchipping pet animals, I have had the opportunity to use this technology in zoo and wild animals. More than 50 wild caught leopards have been microchipped as a part of our research project and this has already provided powerful information, which is helping the Forest Department deal with the Human-Leopard conflict effectively.
For the recommended sites of microchipping in various species, refer www.wsava.org/site1099.htm
References
1) Athreya, V.R. & A.V.Belsare. 2005. Training Maharashtra Forest Department personnel to use chemical restraint and microchips to better manage man-leopard conflict. Report submitted to the Rufford Maurice Laing Foundation, U.K.
2) Belsare, A.V., Athreya, V.R., Thakur, S.T. & S.Chaudhuri. 2004.Life-long Identification Microchips in Leopards Caught in Conflict Areas in Maharashtra, India Cat News No.41
3) Trovan User Manual
Picture 1.Scanning for microchip in an immobilized male leopard with a pocket scanner
ÓVidya Athreya
Picture 2. Microchipping a Labrador pup with DESTRON ISO chip.
ÓGauri Nargolkar
Picture 3. Injector, TROVAN microchips, TROVAN pocket reader and DESTRON microchip
ÓGauri Nargolkar