Animal Identification & Tracing: An Overview


An animal identification system traces the whereabouts and movement of certain animals. Different methods of animal identification, such as branding, have been used for thousands of years, but typically as a way of proving ownership, rather than as a method of animal identification.  However, beginning in the 1940s, animal identification has also focused on the whereabouts and movement of certain animals.  At that time, state and federal programs tracing movement of livestock involved in disease outbreaks were instituted for some diseases in cattle, swine & sheep, and some of these programs, such as National Scrapie Eradication Program, are still in place and effective today.

While government officials and private industry had been working on the issue of livestock traceability prior to the discovery of bovine spongiform encephalopathy in late 2003, USDA announced that it would expedite its efforts in the wake of the discovery.  On April 27, 2004 then-Secretary Veneman announced a framework for the implementation of the system called the National Animal Identification System (“NAIS”) that was developed with the collaboration of USDA, private industry, and state animal health officials and is largely based on earlier work done with the United States Animal Identification Plan.  NAIS encompassed state and federal programs that traced the movement of livestock involved in disease outbreaks such as brucellosis in cattle, bison, and swine, tuberculosis in cattle and cervids, scrapie in sheep and goats and pseudorabies in swine.  When fully implemented, the NAIS program was meant to provide information on the whereabouts of animals from its original birthplace to its death at the slaughter plan, but did not include further tracing of the meat through the plant to the consumer. The ultimate goal of NAIS was to be able to trace all livestock and poultry within 48 hours of a certain event such as a disease outbreak.

However, NAIS was not well received in some sectors of the livestock industry and general public.  As a result, in February of 2010, Vilsack announced that USDA was ending the NAIS program.  Subsequently, USDA drafted a new rule establishing general regulations for improving the traceability of U.S. livestock moving interstate.  After the notice-and-comment rulemaking process, the rule became effective on March 11, 2013.  Under the final rule, unless specifically exempted, livestock moved interstate must be officially identified and accompanied by an interstate certificate of veterinary inspection or other documentation, such as owner-shipper statements or brand certificates.

“NAIS-Type” Identification Programs

Because of the federal focus on interstate travel and traceability, state governments are left with a large amount of discretion in deciding what form animal identification will take within their state.  Further, in the press conference discussing the discontinuation of the NAIS program, Secretary Vilsack made it clear that states could use the NAIS program as a framework for their identification system, if they wished to do so.  As a result, it is important to know the specifics of the NAIS program and the legal concerns involved with its implementation.

While the NAIS program was voluntary on the federal level, some states mandated portions of it on the state level.  These include mandatory premises identification in Wisconsin and Indiana and mandatory premises and cattle identification in Michigan. Of the remaining states, the majority have implemented sections of the NAIS program on a voluntary basis.  In general, NAIS addressed the need for fundamental information in the system: identification of premises where animals may spend time (including farms, auction markets, and meatpacking plants), identification of the animals (either on an individual or lot basis, depending on species), and a record of the animals’ movement.

The first part of the NAIS system was called “premises identification.” The purpose of premises registration was to ensure that producers were notified quickly when a disease event might impact their area(s) or their species of animal. In order to take part in this, producers had to register their premises-a location where livestock or poultry are housed or kept-and provide their contact information. A unique premises identification number, or PIN, was then assigned and contact information recorded for that location.

The second step in the NAIS system was “animal identification.” With this step, animals were identified either individually or by group. Individual animals were identified by assigning them a unique animal identification number (AIN) that stayed with an animal throughout its lifetime. The AIN was a 15-digit number beginning with 840, the numeric code for the United States, and available as visual tags, radio frequency identification (RFID) tags, and injectable transponders. The AIN was linked to the premises identification number (PIN) where the animal was kept when identification was first applied. When the manufacturer of the AIN tag distributed them, the specific tag numbers were correlated with the premises to which they are sent. While the NAIS program was in effect, this distribution data was held in USDA’s animal identification number (AIN) management system.

In April 2019, USDA’s Animal Plant Health Inspection Service (APHIS) introduced a proposal to require RFID tags for cattle over 18 months of age. This proposal was challenged in Federal Court, and, ultimately, the USDA ended the proposal in light of industry feedback and current Executive Branch policy. See the APHIS Statement on Animal Disease Traceability here.

The final component of the NAIS system was “animal tracing.”  Information on the movement of animals was provided to state and private sector databases. The databases were owned, managed, maintained and controlled by the private sector or the States, and were requested, according to USDA, only when there was a risk to animal health.

“Traceability for Livestock Moved Interstate” Rule

The current United States system for animal identification and tracing is called the “Traceability for Livestock Moved Interstate” rule. The rule was put into place on January 9, 2013, and it establishes minimum national official identification and documentation requirements for the traceability of livestock moving interstate. The rule covers cattle and bison, sheep and goats, swine, horses and other equines, captive cervids (e.g., deer and elk), and poultry.  Unless otherwise exempt, if the covered animals are moved interstate, they must be officially identified and accompanied by an interstate certificate of veterinary inspection (ICVI) or other movement document.

The requirements do not apply to livestock moving entirely within Tribal land where the tribe has a separate traceability system, or for animals moving across state lines to a custom slaughter facility. Furthermore, certain exemptions exist for species that are moved from a location in one State through another state to a location in the original State. Required methods of identification vary, depending on the animal at issue.  For example, for cattle or bison that move in interstate commerce, one of the following identification methods must be used:

  • Official eartag
  • Brands registered with a recognized brand inspection authority and accompanied by an official brand inspection certificate, if agreed to by the shipping and receiving State or Tribal animal health authorities.
  • Tattoos and other identification methods acceptable to a breed association for registration purposes, when accompanied by a breed registration certificate, provided that those methods are determined to be official by the receiving State or Tribal animal health authorities.
  • Group/lot identification number (GIN) when applicable.

9 CFR 86.4

Legal Concerns with Tracing Programs


Confidentiality of the supplied information, or limiting the individuals with access to it, is a concern of many producers.  There are two ways in which the information may potentially be released in a state that has implemented some form of state-mandated animal tracing.  The first is through that individual state’s Freedom of Information Act (“FOIA”), and the second is through a court subpoena.

Each state and the federal government have some form of FOIA, or “sunshine law,” to contend with.  FOIA is a law that gives the public the right to access governmental agency records by requesting them.  These agencies can either be state or federal, and each level is covered by the appropriate FOIA, state or federal.  Each law defines the information that must be released in a slightly different way but, generally speaking, records maintained by agencies within the executive branch must be released.  These include records that are either created or maintained by an agency and under agency control at the time the request is made.  As a result, potential records affected could include the information that producers have given to the government in conformance with some form of animal-tracing system.  However, FOIA laws on both the state and the federal level are written to include exemptions, or types of records that are not given out.  While one exemption to the federal FOIA (7 U.S.C. §8791) would have prevented NAIS information (under the previous system) from being released, that exemption only protects information held by federal agencies.  Under the new system, animal identification is owned, led and administered by the individual states, rather than the federal government, the information that is protected varies from state to state.  Some states have created exemptions for the information, while others have not.  For a listing of and discussion about the states that have limited disclosure of animal identification information, please read the Center publication .  To read each state’s statutory language itself, please see the Compilation of Animal Identification Statutes.

The second method through which information may potentially be released is through a court’s subpoena power. Private parties in the course of litigation can request a subpoena from the judge, ordering the release of certain information relevant to a case. Information that is exempted under FOIA is not automatically immune from subpoena. Instead, it may be obtained through discovery if the party’s need for information exceeds the government’s need for confidentiality. As a result, the court has the responsibility of balancing the interests of the two parties and deciding whether the information should be released. No cases have considered whether NAIS information is able to be released through the use of a subpoena. The final concern in confidentiality and privacy exists in a situation where the information is held by a private party. While FOIA might not apply to animal tracing information because it is created and maintained by a private party, privacy issues that should be considered involve the private contract between the provider and maintainer of information, and how much those contracts allow or restrict the sharing of information.


According to USDA, NAIS “will not expose producers to unwarranted or additional liability.” This is an accurate statement for both the original NAIS system and for any state level comparable program because producers have always been responsible for the animals they sell, and that will not change. However, any form of animal traceability system helps identify livestock producers in the chain of custody for particular animals. This identification increases the accountability for individuals who until now have been anonymous. In turn, this makes it easier to determine who mismanaged the animal, which can lead to increased liability exposure for that mismanager. However, the degree to which the system increases exposure may be limited, depending on how far the system is able to trace the animal.

However, if liability can be imposed, it would more than likely be through one of three theories of liability- warranty theory, strict liability or negligence. Under the warranty theory, producers might be held responsible under an “implied warranty of merchantability,” a law adopted in most states in their commercial code, which is a set of laws regulating sales and usually based on the Uniform Commercial Code. The implied warranty of merchantability states that a merchant who sells goods warrants that those goods are fit for the ordinary purposes for which they were sold. However, this might not be the most likely theory of liability, for two reasons. First, courts have been reluctant to consider livestock producers as “merchants.” Since only merchants can give warranties, if the producers are not considered merchants, they cannot be held responsible under this theory. The second reason is that many states in which animal agriculture is a major part of the economy limit livestock producers’ exposure under a warranty theory of liability. For more information on these state limitations to warranties, please see Center publication Approaching Liability with Animal Identification.

Under the theory of strict liability, an individual who has introduced a defective product that is unreasonably dangerous into the stream of commerce may be held liable. However, this may not be a likely way to hold producers responsible, as courts have been reluctant to consider animals to be “products.”

The most likely theory under which liability would attach is negligence. Negligence is the failure to exercise reasonable care. Examples of negligence might include administering illegal drugs or ignoring withdrawal times. Negligence can lead to liability if the plaintiff can prove that the producer failed to use reasonable care and that the failure caused plaintiff’s injury, the producer may be held responsible. Negligence can be reduced or even eliminated through the use and documentation of best management practices on the animals, since those best management practices are the practices that a reasonable person would practice.


The regulatory structure surrounding animal identification is, on the federal level, at least, solely focused on interstate movement of livestock.  This leaves the regulation of intra-state movement to be governed by state and/or local governments., No matter what system of animal traceability each state eventually finalizes, the government’s approach, on the state and federal level, to the precise data requirements and maintenance of information will certainly affect participants of the livestock industry. For more information related to animal identification, please visit the Country of Origin Labeling Reading Room and the Food Safety Reading Room.