Equine Identification in the United States
The need for horse identification spans back to the 1800s, when branding cattle and horses was commonplace for tracing them to specific ranches or owners. Historically, horses were identified by physical description. With many solid horses without unique identifying markings, this identification modality had limited usefulness. For example, it would be challenging to individually describe a group of yearling Friesian fillies in a field.

The transition to utilization of individual animal brands and lip tattoos aided in the identification of equine in the United States. Unfortunately, the recognized disadvantages of these identification modalities include inducing pain and stress in the animal, potential transmission of disease agents, and inherent safety issues associated with the procedures. Additionally, brands can be difficult to read, altered, and considered unsightly.

Over the years, the industry has researched innovative ways to uniquely identify horses. Iris scanning was developed by Japanese researchers in 2000, but the expense of this process and limited access to reading equipment made this a nonviable option. The recent advances in microchip technology has made this procedure the desired identification modality of the future.

Today, the international standards for acceptable microchips are:

  • ISO 11784/11785 compliant and ICAR certified;
  • 15-digit numeric, no letters format; and
  • 134.2 kHz frequency.

Concerns have been raised regarding impact of the invasive procedure and longevity of the microchip. However, subsequent microchip implantation studies have proven that microchip administration yields minor transient pain and inflammation at the injection site and minimal microchip migration following the correct implantation in a horse.

Recently, improved microchip temperature sensing technology has enabled accurate body temperature recording. Not only does this type of chip provide a unique individual identification, but it also provides a value-added health monitoring benefit. For example, should an equine herpesvirus myeloencephalopathy incident occur at a large boarding facility, management could easily and rapidly monitor temperatures via the biothermal microchip and move horses with elevated temperatures to isolation before the horses start shedding virus.

In the last five years, the equine industry in the United States has embraced the use of microchips for equine identification. In 2008, the Jockey Club began offering microchips for sale to its members, and it began mandating that thoroughbred foals have an ISO 11784/11785 compliant microchip implanted starting with the 2017 foal crop. Impressively, Jockey Club members embraced microchipping technology and two-thirds of the 2016 foal crop were voluntarily microchipped. Recognizing the need and benefit of microchipping, the United States Hunter Jumper Association (USHJA) passed a regulation change requiring microchips starting in the 2018 competition year. During that competition year, any horse wishing to participate in the USHJA points program will require a microchip and for the 2019 competition year, a microchip will be required for all horses competing in USHJA competitions.

At the recent Equine Identification Forum in January 2017, the industry recognized the great strides that have been taken related to equine identification but agreed that additional efforts are necessary for industry wide acceptance of microchipping. For more information on the Forum discussions visit animalagriculture.org/proceedings/equineidforum.

CONTACT: Katie Flynn, BVMS—kflynn@cdfa.ca.gov—916/900-5039—Equine Staff Veterinarian—California Department of Food and Agriculture Animal Health Branch, Sacramento, California

This is an excerpt from Equine Disease Quarterly, funded by underwriters at Lloyd’s, London.