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Regardless of the methodology, each has its proper application.
Editor's Note: This month Dr. Kane will review natural and manmade horse identification modalities. Next month, he will explain technological modalities, including microchips and the United States Animal Identification Plan.
There are several methods of horse identification, some natural, some manmade.
When foals are registered, identification photos are taken.
Regardless of the methodology, each has its proper application. Though some may be fallible in specific circumstances, the proper choice is the one that is most useful, convenient and easily recognizable.
Up to now, each horse registry or organization has chosen a method/s that suits its purpose. This review of horse identification methodologies provides basic information for the equine practitioner and his/her clients. With the pending advent of the United States Animal Identification Plan, some of this discussion might be moot, though, regardless of what may be the mandated modality in the future, other methods of horse identification might still be viable as adjunct forms of identification.
Natural I.D. methods
Long before there were any other methodologies for horse identification, there were the natural characteristics of signalment, the visual markings that distinguish one horse from another.
The pattern on the surface of chestnuts (horny epithelium) is unique to each horse. Impressions can be made of them using fingerprint-like technology.
Though many of these features are not as distinctive as chestnuts or DNA-based information, they do represent genetic phenotypical characteristics, and provide the horse owner with quick visual evaluation and simple recognition.
Signalment includes coat color, and markings such as facial blaze and foot stockings, or the elaborate coat-color patterns of a Pinto.
Coat color and markings are not unique enough to be absolute evidence for determining horse identity, and unfortunately can be altered by a skilled unscrupulous horse thief.
More distinctive, as are human fingerprints, are the oval plates of horny epithelium called chestnuts. These callosities growing like the hoof from enlarged papillae of the skin, are found on the inner face of the forearm, above the carpal joint in all species of Equidae, and in the horse, occur near the upper extremity of the inner face of the metatarsus, on the inside of the foreleg above the knee or on the inner surface of the hock.
They are evidently rudimentary structures, which it is suggested may represent glands (Lydekker, Proc. Zool. Soc. London, 1903, vol. i.), or are thought to be remnants of the first toe.
The pattern on the surface of chestnuts is unique to each horse. Impressions can be made of them using fingerprint-like technology. Like coat markings, unfortunately, they, too, are easily altered (surgically), and can be done so by the same skilled dishonest horse thief.
Similarly distinctive as coat markings or chestnuts, are the trichoglyphs or hair whorls, found throughout the coat pattern, especially on the neck.
Both the Morgan and Thoroughbred registries use these "cowlick" patterns within their records. These whorls are naturally formed during embryonic development and remain throughout the horse's lifetime.
- DNA testing and blood typing
The horse's tissue, as per any species, lends itself to identification markers.
Though no outer body tag is visible, DNA testing and blood typing provide a foolproof indicator of absolute recognition. Both methods are commonly used in horses for paternity and registration verification. If an animal has a DNA test on file, this technique may be used for theft or loss detection as well.
"The DNA of equines, depending on what part of the DNA one is looking at, may be very similar to what we see in people, or very dissimilar," says Joy Halverson, DVM, director of QuestGen Forensics. "It can also be very similar between individual horses, or if you look in a different place, it can be very dissimilar. It is the dissimilar parts of the DNA that are used for identification."
Just as one would do forensics, crime scene investigation, and paternity testing in humans, scientists can use the very same technology on any animal, including horses. There are no aspects of the technology regarding horses that make it any different. The same genetic markers used in people are widely available for horses, and have been used for about a decade to do paternity testing in horses for various equine registries. The same type of technology is also used for identification.
Barring a twin, one can analyze DNA markers and come up with an individual identity for a given horse.
In order to run a test, it is fairly common in horses to use plucked or pulled hairs from the mane or tail, rather than a blood sample. If you pull them correctly, you'll have the "rootbulb" material at the end of the hair. It contains plenty of DNA. It makes it a lot easier than having to collect a blood sample.
"A veterinarian should take a cluster of no more than five to 10 hairs from the mane or tail, and wrap it around the fingers with a nice slow pull, not 'yanking' the hairs," Halverson suggests.
The rootbulb material is then sent to the lab for testing.
The downside of DNA testing is that it is not an instantaneous identification system, like other methods such as a microchip or a visible mark. It takes time to process the sample and obtain the identification information. It can be done on an emergency basis within a day, but normally it takes a few days to a week to receive the results. Normally, there is no rush for paternity testing. There is nothing quirky to DNA testing. It is pretty straightforward.
" It is completely tamper - proof ," says Halverson , " Unlike a microchip , you can ' t remove the horse ' s DNA !"
Blood typing for horses was developed a few decades ago and was the technology used for identification and parentage until DNA-based testing was available. It is still being done in some of the small equine registries.
It is not as specific as DNA, but it is more specific than blood typing for humans (ABO Testing), since there are more blood types available (A, C, D, K, P, Q, U).
With DNA testing it is easier to add additional markers and get that extra bit of information that can identify closely related individuals. With blood typing you may have some difficulty in absolute identification when two individuals are closely related.
Once you've done a paternity test, you have generated a genetic profile for three animals (sire, dam and offspring).
With the genotypes of the three animals known, all the genetic material you see in the offspring has to be accounted for in the parents.
If you see something in the foal that is not consistent with the parents then you know the parentage is not accurate, or were incorrectly recorded. If there is a previous DNA test on file, then the identity of a lost or stolen animal can be determined.
Any horse registered with the Jockey Club or Quarter Horse Association is required to be DNA tested.
"As part of a Thoroughbred foal's registration process, we require DNA typing be performed on the foal, to ensure that it qualifies as the offspring of its reported sire and dam," explains John Cooney, director of communications, The Jockey Club. "Before we actually issue registration papers, a certificate of foal registration, the DNA typing of the foal has to check out."
For additional information on DNA-based testing, log onto .
- Iris and retinal scanning
Another technology that is cutting-edge is iris and retinal scanning.
It was recently discussed (NIAA, 2002 Proceedings) as plausible for equine identification.
Iris scan biometrics (now in use for people) employs the unique characteristics and features of the equine iris in order to verify the identity of an individual.
The iris-scan process begins with a photograph. A specialized camera, typically very close to the subject, uses an infrared imager to illuminate the eye and capture a very high-resolution photograph.
This process takes only one to two seconds and provides the details of the iris that are mapped, recorded and stored for future matching/verification. For people, the inaccuracy rating is one in 1.2 million, a highly reliable methodology. By comparison, misidentification with human fingerprinting is one in 1,000.
Retinal scanning analyzes the layer of blood vessels at the back of the eye.
Scanning involves using a low-intensity light source and an optical coupler, and can read the patterns at a great level of accuracy. Retina scan devices (in use for people) are probably the most accurate biometric available today.
For humans, the continuity of the retinal pattern throughout life and the difficulty in fooling such a device make it a great long-term, high-security option. It may be adoptable for equine identification.
- Freeze branding
Freeze branding uses a branding iron, soaked in liquid nitrogen, to create a visible mark of white hair growth on a dark-coated horse, or a bald mark on white or gray horses.
The iron is applied for a few seconds on color-coated horses, or up to 45 seconds on white or light-colored animals.
Immediately after the freeze branding, a frozen indentation in the skin of the animal is seen. Within a few minutes, the indentation will disappear and swelling will begin. The brand will be swollen for 48 to 72 hours. Within three to four weeks, the branded area will begin to get flaky and scaly. Once this scab is gone, white hair will replace the colored hair and the brand will be easily visible. Since the skin is not broken and there is little or no pain, freeze branding is only mildly stressful to the horse, and unlike hot-iron branding, there is no risk of infection, since there is no burn or harm to the underlying skin. Only the hair follicle is affected.
Freeze mark branding uses a branding iron soaked in liquid nitrogen to create a visible mark of white hair growth on a dark horse or a bald mark on a light horse.
The liquid nitrogen cold brand causes the pigment in the hair to "disappear" and leaves the affected hairs white. Little restraint is necessary as the freeze brand is applied. The horse feels little, if any pain during the quick process.
- Freeze Mark Branding
Freeze mark branding is similar to freeze branding. It places an alpha-numeric angle system of marks on the horse to provide a specific horse number (much like the vehicle identification number on a car) which can be passed on to horse-theft organizations to identify lost or stolen horses, or those mistakenly ending up in slaughterhouses.
The brand is usually placed on the neck area below the mane and easily spotted and read. Unlike the freeze brand, the freeze mark not only identifies the owner but the specific horse in question. Kryo-Kinetics Associates, Inc. (KKA), Tuscon, Ariz., provides technicians to apply the mark, and keeps records of the alpha-numeric system to ensure horse identity. The mark begins with an alphabetical symbol, either a symbol that designates the breed of the horse, or its stated domicile. An "A" symbol, for example, is put in eight different positions, Appaloosa, AL, AK, AZ, and AR, etc.
Then there are two digits that are stacked, which represent the year of its birth. Then the last six digits represent either the horse's registration number, with the breed symbol at the beginning of the mark, or a number that has been assigned to the horse by the technician.
"I find that the majority of horse owners want this as theft prevention," says Dee Griesser, KKA, "They know that permanent (and recognizable) ID is best to protect their horse."
This particular ID system allows a horse to be entered into the National Crime Information Center (NCIC) computer, and it doesn't take a whole lot for an officer to read a freeze mark.
"If I steal your horse, and I've got it in my pasture and you show up and say, 'I think that's my horse, we need to scan it with a microchip reader', an officer of the law cannot come on my property unless I give him permission to do so. On the other hand the officer, can, with a pair of binoculars, read a freeze mark from the other side of a fence.
"The Bureau of Land Management (BLM) has always indicated to me," Griesser continues, "that they like it because they do not have to capture a horse to read its ID; they can do so from a distance."
The BLM does use freeze-mark ID on all of their "adopt-a-horse and burros." Also, in the early 1970's a federal regulation was passed which holds slaughter plants responsible for undocumented freeze-mark hide. The protection that the wild horses enjoy carries over to domestic horses as well, since a slaughterhouse operator will make sure to check for a freeze mark.
The drawback to this, as with other methods of ID, is that a freeze mark, like any other mark, may be altered.
- Lip Tattoo
For more than 50 years, the Thoroughbred racing industry has made lip tattoos the standard, preferred identification method.
It's an easy and convenient means of identification at the racetrack.
The critical nature of racing and the value of Thoroughbreds demand an accurate and reliable identification method.
Though tattoos may possibly be altered, they are an excellent method to simply apply and view the proper identity of these valuable animals. Not only Thoroughbreds, but also other breed registries, such as the Appaloosa Horse Club, as well as the U.S. Trotting Association (Standardbreds) and the American Quarter Horse Association, use lip tattoos for primary identification.
When a Thoroughbred is being prepared for the racetrack, before it starts in its first race, it will need a lip tattoo.
The Thoroughbred Racing Protective Bureau (TRPB) provides technicians to properly identify (via the Jockey Club certificate of registration) tattoo and photograph Thoroughbreds throughout the U.S. and Canada. Tattoos ensure that each horse is who it is supposed to be. Lip tattoos are applied to the gum of the inside of the upper lip and are encoded with numbers and a letter, which represent both the individual horse and the year of its birth. Once inked, the technician presses the pins into the gum tissue. Afterward the technician photographs the completed tattooed lip. Prior to the tattooing procedure, the horse is properly acknowledged via its registration materials and appearance (a written description and photo) to ensure the accuracy of its identity.
The Thoroughbred racing industry and other breed registeries have made lip tattoos the standard, preferred identification method.
Once the animal is properly verified, the identifier and technician complete the process.
"The process is not very painful at all," comments Gerald Bergsma, DVM, track veterinarian, Emerald Downs, Auburn Wash. "A small percentage of horses may need to be tranquilized, but generally most horses just stand without any problem, they tolerate it very well."
It is mandatory to lip tattoo those Thoroughbred horses participating in racing, that go to the track, are in training, and have been entered in a race.
The tattoos always start with the year of birth's letter designation (each year is assigned a particular letter) followed by the actual birth year, followed by the last five digits of their Jockey Club registration number. The recent letters are: A 1997, B 1998, C 1999, D 2000, E 2001, F 2002, G 2003, H 2004.
Via lip tattoos, racing commissions across the U.S. require racehorse identities to be verified at race time.
Each State Racing Commission makes its own rules regarding lip tattoos.
Following is Title 11: Alcohol, Horse Racing, and Lottery, Chapter I, Illinois Racing Board, Part 1415, Section 1415.15, Lip Tattoo. "No horse will be permitted to start at a pari-mutuel meeting unless it has been tattooed on the upper lip with his identification number. However, the requirement of a lip tattoo shall not apply to horses entered in stakes races when such horses are fully identified pursuant to the provisions of rule 193 (11 Ill. Adm. Code Section 1415.10) and when such horses have raced at pari-mutuel meetings outside of North America (Source: Amended at 5 Ill. Reg. 8911, effective August 25, 1981)."
Prior to every race, a state employee will check both the tattoo and the written description of the horse. When a horse is brought over from the barn area to the saddling enclosure or paddock, prior to a race, the official horse identifier, can flip its lip, read its tattoo, and make sure that the tattoo matches the one listed on its registration papers.
Dr. Kane earned his doctorate in equine nutrition and physiology from the University of Kentucky in 1978. He works within the animal feed industry with a specialty in horses.