There are no differences.  The microchips that are implanted in horses are the same microchips that are implanted in cats and dogs.  However, the difference lies in the registries.  As previously noted, a microchip has no value without a registry or database to house information related to each microchip.  The cat and dog (pet) registries are numerous:   Petlink, HomeAgain, Petkey, 24 PetWatch are only a few examples.  Due to the large number of pet registries, the small-animal vet community created an online pet microchip lookup tool.   This tool is designed for the pet microchip infrastructure, and does not accept equine registries.   Some pet registries will enroll horses, but there is no value in registering a horse in these registries because they are not designed for, nor are they used by the horse industry or equine veterinarians.

Until recently, there has been very little reason to microchip horses.  Unlike cats and dogs, they typically don’t run away from home so why microchip a horse?   However, there has been an increasing awareness of Microchipping in the horse community, and a number of entities that now require microchipping.

The Equine Rescue Network has implemented a growing nationwide network of 215,000+ individuals and volunteer who now scan horses at auctions and killpens.  If a slaughter-bound horse is found with a microchip or tattoo, ERN is able to notify previous owners.  Understandably, no one wants to get a call that a previously owned horse is about to ship to Canada or Mexico for slaughter.   Yet ERN has found that 85% of the time, the previous owners welcome the call and are happy to help, even if as a means to humanely euthanize the horse.

The veterinary association and scholarly articles have tested the migration of microchips and have reported no evidence that support migration of microchips. The international ‘Universal Injection Site’ for equine microchip implantation has also been established.  Today the microchip is installed into the nuchal ligament, effectively eliminating migration.  See Stien, Geller, Carter (2003).

Unreadable chips:  Microchips are implanted in the nuchal ligamenton the left side of the neck.  It is extremely, extremely rare that a microchip will fail; most readability issues are with the scanner.  However, the scanner problem has been solved by the International Standard Organization (ISO) who set global standard for microchips so that all ISO microchips can be read by any universal scanners (at 134.2 kHz frequency).

The Equine Protection Registry is a database that is designed specifically for horses.   It is the best registry for horses in that they are connected to Animal Control officer and the Equine Rescue Network through a 24 hour hotline number.   Missing horses are put on an emergency ‘Hot List Alert’ and notification is sent by email or phone to Equine Rescue Network, Other Rescue groups, State brand inspectors, Texas Rangers, and partner veterinarians.  If a horse with a registered microchip is ‘Found’ by a volunteer at auction or killpen, ERN access the emergency contact numbers in the Equine Protection Registry to connect a horse with former owners.

There are 9.2 million horses in the USA.  Keeping track of those 9.2 million horses is becoming increasingly difficult using traditional measures of unique markings and naming conventions.  There is no mistaken identity with Microchips.  Unlike brands and tattoos, Microchips cannot be altered, deleted or removed without notable scaring and damage.  Microchipping is an asset to many breeds with common appearances, like Fresians where one Fresian gelding looks identical to the next Fresian gelding.  Microchips make identification simple, fast and accurate.  Additional benefits are noted below:

• ~ Permanent ID that cannot be separated from the animal
• ~ Not alterable (Read Only Technology)
• ~ Helps prevent theft and aids in recovery
• ~ Disaster recovery
• ~ Provides mobile access to online health certificates and medical records
• ~ Facilitates farm management
• ~ Provides accuracy at Competitions and Equine Events
• ~ Required for most travel documentation (Example: Microchip is required for International Horse Passport)
• ~ Identification for sales documentation
• ~ Integrity of show and pedigree records
• ~ Can be implanted in foals just after birth
• ~ Easy to administer
• ~ Study shows less trauma to the horse
• ~ Slaughter horse management
• ~  There is a national HOTLINE for available for microchipped horses:  24/7/365 for animal control and crisis management
• Who is Microchipping?  Below are just a few examples of organizations and governments that currently require microchipping:
• ~  The FEI requires microchipping
• ~  Oldenburg Horse Breeders Society requires microchipping
• ~  United Kingdom, Horse Passports require Microchipping as of 2009
• ~  Microchip is required for horses entering Canada from European Union Member States
• ~  2014/15 Equestrian Australia states – All Horses must be microchipped (Compulsory from 1st July 2008) according to the Australian Standard AS 5018/5019
• ~  A result of the 2006 National Animal Disaster Summit determined that all animals rescued during a disaster will be implanted with microchips
• ~  January 2008 it has been a legal requirement in France for all equines to be microchipped
• ~  DSPCA (Dublin, Ireland) 2009 Passport requires Microchip for equines
• ~  Louisiana Department of Agriculture and Forestry (LDAF) issued a regulation requiring permanent identification (in the form of a brand, lip tattoo or electronic identification)
• ~  Dutch Warmblood horses are no longer branded, instead all horses are required to have a microchip
• …..AND there are many more…..

Many animal and horse owners are reluctant to microchip given the propaganda over the Internet related to animal welfare and microchips.  The American Veterinary Medical Association supports microchipping for animal welfare.  The American Association of Equine Practitioners also recommends microchipping as a means to identify horses and protect horses during national disasters.

The American Veterinary Medical Association is a valuable source of information regarding the adverse effects of microchips.  They note:

“British Small Animal Veterinary Association (BSAVA) maintains a database of adverse reactions to microchips. Since the database was started in 1996, over 4 million animals have been microchipped and only 391 adverse reactions have been reported. Of these reactions, migration of the microchip from its original implantation site is the most common problem reported. Other problems, such as failure of the microchip, hair loss, infection, swelling, and tumor formation, were reported in much lower numbers.”

The issue of tumorand cancer has surfaced and re-surfaced over the years.  The scholarly literature and veterinary associations explain there is little direct evidence that support the relationship between cancers, tumors and microchips.  Given there are 15 million animals who now have microchip implants, if there is a correlation between microchips and cancer/tumors, it is not statistically significant enough to cause concern.  The AVMA report:

There have been reports that mice and rats developed cancer associated with implanted microchips. However, the majority of these mice and rats were being used for cancer studies when the tumors were found, and the rat and mice strains used in the studies are known to be more likely to develop cancer. Tumors associated with microchips in two dogs and two cats have been reported, but in at least one dog and one cat the tumor could not be directly linked to the microchip itself (and may have been caused by something else).