National Animal Identification System for Cattle

Dr. William B. Epperson, Extension Veterinarian, Department of Preventive Veterinary Medicine, Ohio State University 

Overview and Objectives

The National Animal Identification System (NAIS) is a voluntary program administered by USDA in cooperation with State/Tribal governments to provide a nationwide system for unique identification of animals and to allow tracking of animal movements. The stated mission of the NAIS is to provide the capability to identify all animals and premises that have had direct contact with a foreign animal or domestic disease of concern within 48 hours after discovery. A nationwide animal identification system would:

1. Enhance foreign animal disease surveillance, control, and eradication,
2. Improve biosecurity of the national livestock population,
3. Provide positive identification for animals from herds participating in voluntary or mandatory disease control/eradication programs,
4. Allow accurate identification and sourcing of biological products for medical or diagnostic use that originate from animals, and
5. Facilitate health certification of herds in states and regions of the US for purposes of export or international trade ("regionalization").

Forms of Animal Identification

Since the late 1800's, hot iron brands have been used for identification of cattle, and they still serve as a legal means of identification for purposes of ownership in many western states. Brands are inexpensive, simple, and visually clear. Disadvantages include the necessity to re-brand as ownership changes, concerns with animal welfare, and the hide damage associated with brands. Brands are read and interpreted by visual means, so may not be easily adaptable to automated high throughput reader systems.

Ear notches have been used in swine and cattle and have similar advantages and disadvantages as brands. Uniquely identifying animals across herds and time is the main disadvantage to ear notches.

Ear tags/back tags and other visually read devices are commonly used today. They are easy to apply and scale neutral. However, reading tags and reporting tag numbers is labor intensive. In addition, a system must be in place to provide unique identification over time and between states.

Nose prints have been used in exhibitions. They are unique to the animal but can be difficult to read on a recurring basis.

Electronic identification includes radio frequency identification device (RFID) ear tags. This is presently the technology of choice. These are moderately inexpensive devices to apply but require some specialized reader equipment. They support automated data capture, though are not tamperproof and can be lost. The RFID implantable devices (chips) are available, but there is concern that those devices may migrate in the body.

Retinal imaging uses a picture of blood vessels in the retina to verify identification. Retinal vessel pattern is said to be unique to each individual and does not change through the life of the animal - similar to fingerprints. Retinal imaging does require a specialized scanner. Currently, a US company "Optibrand" is developing this technology. Retinal imaging is tamperproof and has been used to verify identity for exhibition and for specific marketing programs. Its sister technology, iris imaging, has lost popularity since the iris changes through life and images are difficult to acquire.

DNA fingerprinting is probably the ultimate in identity verification. At present, it is not practical in the field.

The Need for a National System

The need to track animals was evident following discovery of a Washington cow with Bovine Spongiform Encephalopathy (BSE) on December 23, 2003. The European Union, Australia, and Canada ( have or will have animal identification and systems capable of lifetime tracking of an animal. This sort of system will become an expectation of countries exporting and importing animals or animal products. Animal identification is an element in the procedures and Standards of Veterinary Services in the 2004 Terrestrial Animal Health Code published by the Office of International des Epizooties (OIE), so it appears that a nationwide animal identification system will ultimately be necessary for the US to effectively compete in international trade.

Today, travel from one point to nearly any other point on the globe is possible within 24 hours. Additionally, livestock enterprises have become increasingly concentrated so that exposure at a major collecting point or large integrated facility would lead to tremendous agent multiplication and/or dispersion in a short period of time. Therefore, compared to years past, the risk of foreign animal disease introduction is probably greater, as well as the risk of transmission.

The Foot and Mouth Disease outbreak in the United Kingdom in 2001 demonstrated the need for animal identification and tracking. That outbreak initiated in swine, but spread to nearby sheep flocks, which showed very few clinical signs (i.e. lameness and mouth lesions) but were able to spread the virus to other animals. The outbreak was not officially detected for some 2 to 3 weeks, due to insidious spread of the barely clinical condition. As a result of this delay, many animals were exposed from contact at marketing centers, and the virus was widely disseminated. Tracking potential contacts in the United Kingdom proved to be an arduous task due to inadequate identification and records of movement. The outbreak halted export of animals and animal products from the entire country, and over 10,400 farms were affected, requiring the slaughter and disposal of 4.2 million animals. Direct government cost to contain the outbreak was $5 billion (US), with losses from tourism estimated at $3.6 to 7.2 billion (US).

A national animal identification program would enable rapid tracking of contacts and allow quarantine of exposed herds before further transmission occurred. It would also potentially allow identification of affected regions of the US and could facilitate more rapid recovery of animal movement and trade in those areas not in the exposed region.

The fact that many foreign animal diseases affect not only food producing animals makes it necessary to include non-food animal species (including horses, cervidae, and camelids) in the national identification program. Knowing potential exposures of these non-food animal species is also important in controlling foreign animal disease outbreaks.

It is likely that voluntary disease control programs will become more commonplace in the future and can offer a niche market to producers. Examples of such programs in place today include those for Johne's disease, Bovine Leukosis Virus, and Bovine Virus Diarrhea. Specialty manufacturers or herds raising transgenic animals have inquired about products (i.e. colostrum) from herds known to be free of specific disease(s). Along similar lines, national identification programs enhance source verification, which has become a major issue of some marketing programs.

The Basic Function

As a first and necessary step, all premises on which animals are housed, managed, or held will need a unique premise identification number. This includes farms, ranches, feedlots, auction barns, and exhibition sites. States are responsible to assign these numbers and maintain a database of the numbers, location, and responsible person to contact in the event of an emergency. Ohio has received $130,000 to install the computer software that will support allocation of the numbers and storage of the necessary information. The Ohio system will be linked to a national system, so that key information will be available to national regulatory authorities. Since animal disease outbreaks often cross multiple state lines, sharing of information involved in disease tracking is necessary.

The RFID ear tags that will be initially used in the NAIS will encode a 15 character code (numbers and letters). Each time an animal is sold or moved to a place where it is co-mingled with other animals, the animal's identification will be reported to the database, allowing exposure and movement of animals to be tracked. As animals are sold or moved, they will compile a series of premise numbers and dates where changes occurred for each premise they resided. All cattle on a single premise will have that one premise number associated with them while they reside on that premise. For example, given a 100-cow herd, each cow will have a unique ear tag number, but all 100 cows will all be associated (in a computer database) with the one premise number of the owner. Animals sold to another owner keep the same ear tag, but a new premise number is associated with the ear tag number in the computer database, reflecting the premise number of the new owner. If an animal is sold through an auction market, then the animal is associated with the premise number of the auction market for the dates it is there, and then is associated with the premise number of the new owner, starting on the date it arrives at the new premise. Each time an animal is sold or commingled, the changes will have to be registered within the national system.


There are currently several fundamental controversies with the program. One is confidentiality from public record - opinions differ as to who should have access to portions of these data. Most producers do not want the information in the public domain, for fear it could be used for purposes other than to track animal health emergencies. From comments made by Undersecretary Bill Hawks at a recent USDA listening session, it appears that the USDA can participate and still maintain confidentiality as long as the program is voluntary.

However, in order to monitor and track animal disease outbreaks, regulators must have access to the data. Very often, animal disease emergencies are completely handled by state regulators, so it is important that they have access to this information. Basically, access to the national identification database allows regulators to do their job better and faster - which benefits the livestock industry. Denying them access places the industry in some jeopardy in the event of an animal health emergency.

The second big controversy is funding. Who will pay to start this program, and how will it be maintained? The true cost of the NAIS is not known, though many cost estimates have been made. A seemingly popular estimate is for a cost of around $75 million per year for the next 3 to 5 years. The USDA released $20.3 million earlier this summer for NAIS, and the 2005 fiscal budget proposes another $33 million. The NAIS is being proposed as a government-industry cooperative program, with each partner sharing the cost.

Immediate Outlook

Premise numbers for Ohio locations will start to be issued on a larger scale in calendar year 2005. Specific instructions on how that is to be done will come from the Ohio Department of Agriculture. This will be a ramp-up process and will involve not only producers, but veterinarians, auction markets, order buyers, and packers. This is an obvious burden, especially to auction markets and packers. Projecting timelines beyond this year are tenuous. Much depends on how implementation goes, but interested persons can go to to view some projections.

1. The National Animal Identification System - at
2. The United States Animal Identification Plan - at
3. Stanford, K., J. Stitt , J.A. Kellar , and T.A. McAllister. 2001. Traceability in cattle and small ruminants in Canada. Rev. Sci. Tech. Off. Int. Epitz 20(2) 510-522.
4. Premises identification - the first step toward a national animal identification system. Program Aid No. 1800,
5. Foot and Mouth Disease 2001: Lessons to be Learned Inquiry Report. Available at