Brucellosis Laws in Arizona: What Cattle and Bison Owners Need to Know

Brucellosis is one of the most closely watched livestock diseases in the United States, and Arizona is no exception when it comes to regulating it. If you own cattle, bison, or dairy animals in Arizona, understanding the state’s brucellosis rules is not optional — it is a legal obligation with real consequences if ignored.

This guide walks you through Arizona’s current brucellosis classification, vaccination and testing requirements, movement rules, reporting duties, and the penalties you face for violations. Whether you are a rancher, a dairy operator, or someone importing livestock into the state, knowing these rules protects your herd and your livelihood.

What Is Brucellosis and Why It Is Regulated in Arizona

Brucellosis is a contagious bacterial disease that affects livestock, wildlife, and humans. Also known as contagious abortion or Bang’s disease, it is caused by a group of bacteria in the genus Brucella. In its principal animal hosts, brucellosis causes loss of young through spontaneous abortion or birth of weak offspring, reduced milk production, and infertility.

Brucellosis occurs mainly in cattle, bison, and swine, but can affect other animals — including cervids, goats, sheep, and horses — as well as people. In cattle and bison, the bacteria of concern is Brucella abortus. The disease poses a dual threat: it damages agricultural productivity and carries serious public health implications.

Infected animals may appear healthy, even during pregnancy. However, they can still harbor and spread infectious bacteria and serve as dangerous sources of infection. This is precisely why Arizona, like every other state, maintains an active regulatory framework around brucellosis detection, prevention, and control.

The livestock and dairy industries and the American consumer have realized great financial savings from the success of the Cooperative State-Federal Brucellosis Eradication Program. Annual losses from lowered milk production, aborted calves and pigs, and reduced breeding efficiency have decreased from more than $400 million in 1952 to less than $1 million. Arizona’s regulations are part of this broader national eradication effort.

Arizona’s Brucellosis Classification Status

Arizona holds the highest possible disease classification under the federal system: Class Free. All 50 states, Puerto Rico, and the U.S. Virgin Islands are brucellosis-free, except for the occasional spillover of cases occurring in livestock near the Greater Yellowstone Area due to bison and elk having the disease. Arizona is not near the Greater Yellowstone Area, so it faces no elevated wildlife-spillover risk.

A Class Free State or area is one that meets the standards for classification as such, certified by the State animal health official, the Veterinarian in Charge, and the Administrator. For initial classification or reclassification, all cattle herds in the state must have remained free of Brucella abortus for 12 consecutive months, with a cattle herd infection rate of 0.0 percent or 0 herds per 1,000.

In February 2008, every state, along with Puerto Rico and the U.S. Virgin Islands, achieved Class Free status for the first time in the program’s 74-year history. Arizona has maintained that status continuously since then.

The classifications are Class Free, Class A, Class B, and Class C. States or areas that do not meet the minimum standards for Class C status are required to be placed under Federal quarantine. Restrictions on moving cattle and bison interstate become less stringent as a state or area approaches or achieves Class Free status. Arizona’s Class Free designation benefits ranchers by reducing — though not eliminating — certain testing burdens for intrastate movement.

You can review the current status of all state eradication programs, including brucellosis classifications, through the USDA APHIS Status of Current Eradication Programs page. For comparison, see how neighboring states handle their own frameworks in our guides to brucellosis laws in Nevada and brucellosis laws in Nebraska.

Vaccination Requirements in Arizona

Arizona participates in the national RB51 vaccination program, which is the federally approved vaccine for brucellosis prevention in cattle. There is a vaccine for brucellosis called RB51. Licensed for use in nonpregnant female cattle 4 to 12 months of age, the vaccine provides a significant level of protection — about 70 to 80 percent effective. It is also very effective at preventing abortions, which prevents further disease transmission.

RB51 is available only through an accredited veterinarian, State animal health official, or Federal area veterinarian in charge. You cannot purchase or administer this vaccine on your own — it must be obtained and applied through a properly credentialed professional.

In Arizona, the vaccination status of your cattle directly affects your testing obligations when moving animals across state lines. Some states don’t allow cattle or domestic bison to be moved interstate for breeding without a record of brucellosis vaccination. When importing into Arizona, cattle that carry official calfhood vaccinate status are treated differently under testing rules than non-vaccinated animals.

• Official calfhood vaccinates (OCV): Heifers vaccinated as calves and carrying official vaccinate identification may qualify for reduced testing requirements, depending on their reproductive status and origin state.
• Non-vaccinated heifers and bulls: Subject to stricter testing requirements when entering Arizona from certain states.
• Dairy herds: Arizona requires annual brucellosis testing for dairy herds, which works alongside vaccination protocols to maintain herd health status.

All cattle or domestic bison owners, regardless of location, should discuss the advantages and disadvantages of vaccination with their veterinarian. This is especially important if you regularly move breeding animals across state lines, where vaccination history directly determines testing requirements and quarantine status.

Testing Requirements for Cattle and Bison in Arizona

Arizona’s brucellosis testing requirements vary depending on the type of animal, its origin, its reproductive status, and its intended use. The rules are codified primarily in Arizona Administrative Code § R3-2-612 and Arizona Revised Statutes Title 3, Article 4 (A.R.S. §§ 3-1771 through 3-1776).

Dairy Herd Testing

All dairy herds of cattle and goats shall be tested for brucellosis at intervals as prescribed by the director. The testing shall be made at the expense of the owner of the stock to the extent of the ordinary labor involved in the testing of the cattle. Additionally, producers of raw milk for consumption must have their herds tested annually for tuberculosis and brucellosis.

Imported Cattle and Bison Testing

When you bring cattle or bison into Arizona from another state, the testing requirements depend on the origin state’s brucellosis classification:

1. From a Class Free State with no infected wildlife: If native ranch cattle are from a brucellosis Class Free State that does not have free-ranging brucellosis-infected bison or wildlife, no brucellosis test is required as long as the cattle are moved directly from the ranch of origin to an Arizona destination and the official eartag numbers are listed on a health certificate, or the cattle are from a state that has a brand inspection program approved by the State Veterinarian and the owner’s brand is listed on a brand inspection certificate or health certificate.
2. From a Certified Brucellosis-Free Herd: If cattle or bison originate from a Certified Brucellosis-Free Herd and the herd certification number is documented on the health certificate and import permit, no brucellosis test is required.
3. Bulls and non-vaccinated heifers (12 months or older): The owner or owner’s agent shall ensure that bulls and non-vaccinated heifers test negative for brucellosis if 12 months of age or older, unless consigned for feeding purposes to a designated feedlot.
4. Official calfhood vaccinates (parturient or postparturient): The owner or owner’s agent shall ensure that an official calfhood vaccinate is tested negative for brucellosis within 30 days before entering Arizona if the official calfhood vaccinate is parturient or postparturient.
5. From a Class A State: Beef breeding cattle or breeding bison from a Class A State must remain under import quarantine and isolation until the cattle test negative for brucellosis.

Feedlot-Destined Animals

All cattle or bison consigned to a designated feedlot shall be branded with an “F” adjacent to the tail head before entry into Arizona unless the State Veterinarian grants permission to apply the “F” brand upon arrival. This branding requirement ensures that feedlot animals — which are exempt from certain brucellosis tests — are clearly identified and do not enter the breeding population.

A complete herd blood test must include all cattle or bison six months of age and older, except steers and spayed heifers, unless otherwise specified by a Designated Epidemiologist.

Interstate and Intrastate Movement Rules in Arizona

Movement rules for cattle and bison in Arizona operate on two levels: what is required when bringing animals into Arizona from other states (interstate), and what applies when moving animals within the state (intrastate).

Interstate Movement Into Arizona

The owner of cattle and bison entering Arizona or the owner’s agent shall comply with the requirements in this article. For imported beef breeding cattle, breeding bison, and dairy cattle, an accredited veterinarian must apply official eartag identification to each animal before entry. A Certificate of Veterinary Inspection (CVI) — commonly called a health certificate — is required for all imported breeding cattle and dairy animals.

Within seven days after importation, the owner or owner’s agent shall ensure that the individual official eartag identification for imported dairy cattle is the same as that listed on the health certificate, and the owner or the owner’s agent shall report any discrepancies between the official eartag and the health certificate to the State Veterinarian.

The owner shall notify the State Veterinarian within seven days of moving cattle or bison that are under import quarantine from the destination listed on the import permit and health certificate, and shall notify the State Veterinarian at the time animals are retested for brucellosis if the animals are under import quarantine and are not moved from the destination listed on the import permit and health certificate.

Stockyard and Market Movement

Beef breeding cattle, breeding bison, and dairy cattle that do not meet the standard testing criteria may be imported without a brucellosis test if moved to a specifically approved stockyard and tested before sale or movement from the stockyard. The owner or owner’s agent shall not commingle these cattle or bison with other cattle or bison until they are tested and found to be brucellosis negative.

Slaughter Animals

Animals consigned directly for immediate slaughter to an official state or federal slaughter establishment are generally exempt from brucellosis testing requirements. The owner is not required to notify the State Veterinarian if the cattle or bison are shipped directly to an official state or federal slaughter establishment for immediate slaughter.

For context on how other states manage their movement frameworks, see our overviews of brucellosis laws in Michigan and brucellosis laws in Minnesota.

Reporting and Quarantine Requirements in Arizona

Arizona law requires prompt reporting of suspected or confirmed brucellosis cases, and the state has clear authority to impose quarantines on affected or exposed animals. These requirements apply to veterinarians, livestock owners, and anyone handling potentially infected animals.

Mandatory Reporting

Brucellosis in cattle, bison, swine, and cervidae is a reportable disease under 9 CFR 78, and must be reported immediately to the APHIS Area Veterinarian in Charge (AVIC) and the State Animal Health Official. Arizona veterinarians are required by both state and federal law to report diagnosed or suspected brucellosis cases without delay.

Producers or owners who suspect an animal disease should contact their veterinarian to evaluate the animal or herd. If brucellosis is suspected, you should not move animals off the property until you have guidance from the Arizona State Veterinarian or USDA APHIS.

Quarantine Authority and Procedures

Once a herd is affected, animal health officials quarantine all infected and exposed cattle and bison and limit their movement to slaughter only. This continues until the disease is no longer present in the herd.

Animal health officials also investigate the detection to determine if other herds are affected and identify the most likely source of infection. They develop herd plans for affected herds, possibly exposed herds, and area herds to control, eradicate, and prevent the spread of the disease.

Arizona Administrative Code grants the State Veterinarian authority to issue hold orders on animals that enter the state without meeting import requirements. Failure to comply with entry requirements will incur the following conditions: the owner must pay the expenses incurred by a hold order to test and retest the imported cattle or bison or return them to the state of origin.

Surveillance and Slaughter Testing

The Market Cattle Testing Program governs the testing of cattle and bison at markets (first point of concentration) or slaughter. This program is a key part of Arizona’s ongoing surveillance effort to detect any brucellosis cases before they can spread within the state’s herd population. Federal and State animal health officials jointly conduct surveillance for bovine brucellosis and tuberculosis.

You can reach the Arizona Department of Agriculture’s Animal Services Division — including the State Veterinarian’s office — at (602) 542-4293. For matters involving livestock cruelty or disease-related neglect, the department’s dispatch line is (623) 445-0281. More information is available at the Arizona Department of Agriculture Animal Services page.

Penalties for Brucellosis Violations in Arizona

Arizona takes brucellosis violations seriously. The state has established specific criminal classifications for brucellosis-related offenses under A.R.S. § 3-1776, and violations can result in misdemeanor charges, financial liability, and mandatory corrective action.

Criminal Classification

Under Arizona law, brucellosis control violations under A.R.S. § 3-1776 are classified as misdemeanor offenses. The Arizona Criminal Justice Commission’s offense codes identify three distinct brucellosis-related charges:

• General livestock brucellosis violation (A.R.S. § 3-1776) — covers broad non-compliance with brucellosis control requirements
• Selling an animal with a brucellosis reactor (A.R.S. § 3-1776.1) — applies when a person knowingly sells or transfers an animal that has tested as a brucellosis reactor
• Removing a brucellosis brand or tag (A.R.S. § 3-1776.2) — applies when official brucellosis identification markings are tampered with or removed

All three of these offense codes — livestock brucellosis violation, selling an animal with a brucellosis reactor, and removing a brucellosis brand or tag — are classified as misdemeanor offenses under Arizona law, as reflected in the Arizona Criminal Justice Commission’s current criminal codes.

Financial Liability for Non-Compliance

Beyond criminal penalties, you also face direct financial consequences for failing to meet import and movement requirements. If your animals are placed under a hold order due to non-compliance, you bear the full cost of any required testing, retesting, or return transport. These costs can be substantial for large shipments of breeding cattle.

Federal Consequences

Because Arizona participates in the cooperative State-Federal Brucellosis Eradication Program, serious violations can also trigger federal-level enforcement. The regulations of the APHIS Brucellosis Eradication Program vary based on the brucellosis status of each state. Minimum standards are set forth in the Brucellosis Eradication Uniform Methods and Rules. Violations that affect interstate commerce or undermine federal eradication standards may draw USDA APHIS involvement in addition to state-level action.

Condemnation of Diseased Animals

Under A.R.S. § 3-1742, Arizona grants the State Veterinarian authority to enter premises to inspect animals and condemn diseased livestock. Animals confirmed as brucellosis reactors are subject to quarantine and, in most cases, must be sent directly to slaughter. There is no treatment option available — there is no economically feasible treatment for brucellosis in livestock.

For a broader look at how Arizona regulates livestock and animal ownership, explore our guides to backyard pig laws in Arizona, beekeeping laws in Arizona, and brucellosis laws in Missouri for a multi-state comparison. You may also find our overview of wildlife removal laws in Arizona useful if you are managing land where wildlife and livestock interact.

Conclusion

Arizona’s brucellosis laws exist within a well-established state and federal framework designed to protect livestock health, public safety, and the economic integrity of the cattle and dairy industries. As a livestock owner or operator in Arizona, your key obligations are clear: maintain proper vaccination records, comply with testing requirements based on animal type and origin, follow movement and quarantine rules, and report suspected cases immediately.

Arizona’s Class Free status is an asset for ranchers and producers — it reduces certain regulatory burdens and supports favorable interstate commerce conditions. But that status depends on the continued compliance of every livestock owner in the state. Staying current with the Arizona Department of Agriculture’s requirements and working with an accredited veterinarian are the most reliable ways to protect your herd and stay on the right side of the law.

For the most current and specific guidance, contact the Arizona State Veterinarian’s office at (602) 542-4293 or visit the Arizona Department of Agriculture Animal Services Division online. You can also review the full federal brucellosis eradication regulations at the USDA APHIS Bovine Brucellosis page.