Idaho Brucellosis Laws: What Cattle and Bison Producers Must Know

If you raise cattle or bison in Idaho, brucellosis regulations are not a background concern — they are an active part of how you manage your herd every year. Idaho sits within the Greater Yellowstone Area, one of the only regions in the United States where Brucella abortus still circulates in wild elk populations, creating a persistent spillover risk for livestock that producers in most other states simply do not face.

Understanding Idaho’s brucellosis laws means knowing your state’s classification, which animals must be vaccinated and when, what testing applies to your operation, how movement in and out of the Designated Surveillance Area works, and what happens if a violation occurs. This guide walks through each of those layers so you know exactly where your obligations begin and end.

What Is Brucellosis and Why It Is Regulated in Idaho

Brucellosis is an infectious disease of animals and humans caused by bacteria of the genus Brucella. For cattle and bison producers, the primary concern is Brucella abortus, the species that drives the national eradication program. In infected cattle, the disease causes reproductive failure — most notably late-term abortions, stillbirths, and the birth of weak calves. Infected cows frequently retain their placentas, and bulls may develop orchitis.

Brucellosis can cause abortion, infertility, and sterility, resulting in economic loss to the producer. The bacteria shed during abortions and in milk can survive in the environment for weeks, making contaminated premises a persistent risk to other animals. The disease is also a recognized zoonosis — it can infect people who handle infected animals or consume unpasteurized dairy products.

Idaho’s specific exposure risk comes from its geography. The highest risk of brucellosis in Idaho is in the Designated Surveillance Area (DSA), a region near the Greater Yellowstone Area where there is enhanced surveillance through a cooperative state and federal program. In Yellowstone National Park, wild cervids such as elk can carry the disease, and interaction between cattle and elk is a risk factor.

The state has brucellosis-specific rules administered by the Department of Agriculture — IDAPA 02.04.20, “Rules Governing Brucellosis.” These rules govern vaccination, testing, movement, reporting, and enforcement across the state. You can also review Idaho’s hunting laws for context on how wildlife management intersects with livestock disease risk in the state.

Idaho’s Brucellosis Classification Status

Idaho holds Brucellosis Class Free status under the USDA Animal and Plant Health Inspection Service (APHIS) classification system. Included among the requirements for Class Free status are that the cattle and/or bison herds in the state or area within the state must have remained free from infections with field strains of Brucella abortus for at least 12 months.

Idaho’s path to its current standing has not been straightforward. Idaho enjoyed brucellosis-free status from 1991 until January 2006, when the USDA reduced the rating to Class A after the disease was found in a cattle herd in Swan Valley, east of Idaho Falls near the Wyoming border. The state subsequently worked to regain its standing. Idaho regained its Class Free status from the U.S. Department of Agriculture in July 2007.

While all Greater Yellowstone Area states remain Class Free, the GYA remains the primary focus for brucellosis in livestock because the disease is endemic in wild elk and bison in the GYA. Idaho maintains its Class Free designation today by operating under a USDA-approved Brucellosis Management Plan — a requirement for any Class Free state where wildlife are known to carry B. abortus.

Class Free status carries real economic value for your operation. This recognition allows producers to buy and import beef cattle and bison from these states with reduced vaccination and testing requirements for these two diseases. Losing that status — even temporarily — triggers mandatory pre-movement testing costs and restricts interstate commerce. You can compare how neighboring states handle their own classification obligations by reviewing brucellosis laws in Nevada and brucellosis laws in Nebraska.

Vaccination Requirements for Cattle and Bison in Idaho

Idaho has a mandatory vaccination requirement for female cattle and bison. All intact female cattle and domestic bison must be vaccinated against brucellosis between the ages of 4 and 12 months unless being fed for slaughter in an Idaho approved feedlot. This window is not flexible — animals vaccinated outside the standard age range require additional regulatory steps.

If you are a veterinarian with a client that has intact females over 12 months that have not been vaccinated for brucellosis, you must download the adult vaccination permit and submit it via email or contact the department with questions regarding adult vaccination. Adult vaccinations are not routine and require pre-approval from the Idaho State Department of Agriculture (ISDA).

Any federally accredited veterinarian can perform vaccination for brucellosis. The approved vaccine for cattle and bison is RB51, a strain-19 replacement product licensed by the USDA. Testing is required before any adult brucellosis vaccinations are given. This ensures that animals being vaccinated as adults are not already infected before the procedure.

For imported animals, the vaccination requirement applies at the point of entry. For the most part, resident female cattle and bison require vaccination between 4 and 12 months of age, and female cattle and bison being imported require vaccination if they are 4 months of age or older. Unvaccinated imported females face significant movement restrictions once inside the state.

• Vaccination must be performed by a federally accredited veterinarian
• The vaccination tattoo must be legible and recorded on the Certificate of Veterinary Inspection (CVI)
• Adult vaccination (over 12 months) requires a permit from ISDA before the procedure
• Animals in Idaho-approved feedlots headed directly to slaughter are exempt from the vaccination requirement
• Intact male cattle are not subject to the female-specific vaccination mandate

Testing Requirements for Cattle and Bison in Idaho

Testing obligations in Idaho are primarily tied to your herd’s location relative to the Designated Surveillance Area and to specific activities such as adult vaccination, raw milk production, and certain types of imports.

The Designated Surveillance Area (DSA) was established under IDAPA 02.04.20 “Rules Governing Brucellosis.” The DSA is an area of Idaho where brucellosis seropositive wildlife is known to exist and where comingling of wildlife and livestock may lead to transmission of brucellosis. The DSA covers the southeastern corner of Idaho, bordering Wyoming and the Greater Yellowstone Area.

Test eligible animals are all sexually intact cattle and domestic bison 12 months of age and over, and all parturient and post-parturient cattle and domestic bison, regardless of age. If your animals fall into this category and are located in or have been in the DSA, testing obligations apply before movement.

Regarding testing costs, the costs for tests run at the state laboratory are not charged to producers. However, the costs associated with collecting samples for testing will vary. Contact your veterinarian for a list of fees associated with brucellosis sample collection. Additionally, through a USDA grant, veterinarians can be reimbursed for testing of cattle within the DSA.

Any federally accredited veterinarian can draw blood to test for brucellosis. Contact your veterinarian to schedule sample collection, then confirm results are documented on the appropriate USDA or state forms before movement occurs.

Interstate and Intrastate Movement Rules in Idaho

Idaho’s movement rules differ significantly depending on whether your animals are leaving the DSA, moving within the state outside the DSA, or crossing state lines. Understanding these distinctions protects you from compliance violations that can result in animals being detained or returned.

Intrastate Movement

Other than animals moving out of the Designated Surveillance Area (DSA) for brucellosis, there are no health requirements for movement within the state. If your herd is entirely outside the DSA, you can move cattle and bison within Idaho without brucellosis-specific testing or paperwork. However, you should always verify whether the event or destination has its own requirements.

For animals within the DSA, the rules are more specific. Any cattle and domestic bison leaving the DSA must meet the following requirements: individual, official identification, and a negative brucellosis test for test eligible animals within 30 days before leaving the DSA if the cattle have been in the DSA any time between January 1 and June 15 of any calendar year.

Exceptions to testing are provided for animals going directly to an Idaho approved livestock market or a USDA-inspected slaughter facility located in Idaho. If your animals qualify for this exception, make sure the destination is officially approved before assuming the exemption applies.

Interstate Movement

Some states may require testing of animals moving to their state from anywhere in Idaho. Even though Idaho is Class Free, destination state rules vary — and some states impose their own testing requirements on incoming cattle regardless of the origin state’s classification. Always verify the receiving state’s import requirements before shipping.

For animals being imported into Idaho, vaccination documentation is a central requirement. Females 4 months and older require vaccination for brucellosis with their legible tattoo recorded on the CVI. Unvaccinated females require an entry permit or approved eCVI.

Domestic bison imported into Idaho shall be in compliance with the same requirements as cattle. Additionally, all cattle and Canadian domestic bison imported into Idaho from Canada, except those imported directly to slaughter, must have an import permit prior to importation.

For a broader look at how movement rules compare across state lines, see how Michigan handles brucellosis movement rules and Minnesota’s brucellosis regulations for comparison.

Reporting and Quarantine Requirements in Idaho

When brucellosis is suspected or confirmed in your herd, Idaho law sets clear obligations for both reporting and containment. These requirements exist to prevent further spread and to protect Idaho’s Class Free status at the state level.

Reporting Obligations

Brucellosis is a reportable disease in Idaho. If a veterinarian or producer has reason to suspect infection — based on clinical signs such as late-term abortions, retained placentas, or positive serological results — that suspicion must be reported to the Idaho State Department of Agriculture. The major sources of infection are reproductive (mainly fetal and placental) secretions and mammary secretions (milk) from infected animals, so any unusual pattern of reproductive failure in your herd warrants prompt attention and reporting.

ISDA coordinates closely with USDA APHIS Veterinary Services when a reactor is identified. An epidemiological investigation is initiated to trace the source of infection and identify any exposed herds. Idaho communicates regularly with the other Greater Yellowstone Area states to regularly update their brucellosis program and maintain uniformity across state lines to the greatest extent possible.

Quarantine Authority and Procedures

The Administrator and all state and federal animal health officials are authorized to quarantine any animals affected or infected with, or exposed to any contagious, infectious, or communicable disease where such animals are found, or quarantine to a place designated by the Administrator. For brucellosis specifically, a quarantine is placed on any herd in which a reactor is identified, and it remains in effect until the herd is depopulated or tested clear.

Once reactors are removed or the herd is sent to slaughter, decontamination is required. The Administrator is authorized to order the owner or operator of stockyards, pens, trucks, trailers, cars, vessels, chutes, and other conveyances and premises to clean and disinfect the same, at the owner’s expense, whenever necessary for the eradication of brucellosis.

Premises, conveyances, or other areas where infected animals have been held or kept shall be cleaned and disinfected under regulatory supervision within fifteen (15) days following the removal of reactors or the entire herd for slaughter. The cost of this cleaning and disinfection falls on the owner, not the state or federal agency overseeing the process.

Idaho’s approach to surveillance within the DSA is movement-based rather than calendar-based. Idaho monitors brucellosis in their Designated Surveillance Area cattle by testing animals that change ownership or leave the DSA. Rather than test a certain percentage of DSA herds every year, their “prior-to-movement” testing strategy is the most palatable approach. This means your testing obligation is triggered by activity, not simply by the calendar — but it also means you cannot defer testing indefinitely if you plan to move animals.

Idaho’s animal disease laws are part of a broader regulatory framework. Producers who also keep other livestock should be aware of related state requirements — for example, goat ownership laws in Idaho and backyard chicken laws in Idaho each carry their own disease management and identification requirements.

Penalties for Brucellosis Violations in Idaho

Violations of Idaho’s brucellosis rules carry both criminal and civil consequences. The penalty structure is not limited to fines — it can also include indemnity repayment obligations, movement restrictions, and quarantine costs that fall entirely on the non-compliant producer.

Criminal and Civil Penalties

Any person who violates any of the provisions of this chapter may be subject to the criminal and civil penalties provided in Title 25, Chapters 2, 6, and 35, Idaho Code. Title 25 governs Idaho’s animal industry statutes broadly, and the penalties available under those chapters include misdemeanor criminal charges, civil fines, and administrative enforcement actions.

These rules govern prevention, surveillance, diagnosis, control, management, and eradication of brucellosis in the state of Idaho. Violations can include failing to vaccinate required animals, moving animals out of the DSA without proper testing, importing animals without required documentation, and failing to report suspected infection.

Indemnity and Cost Recovery

When a herd is depopulated due to brucellosis, federal and state indemnity programs may compensate producers for the value of destroyed animals. However, this compensation can be withheld or reduced if the producer failed to comply with vaccination or testing requirements before the infection was identified. Non-compliance at any point in the chain — from vaccination records to movement documentation — can affect your eligibility for indemnity payments.

Cleaning and disinfection costs after a confirmed infection are borne entirely by the owner. Cleaning and disinfecting shall be done under the supervision of state or federal animal health officials, meaning you cannot simply self-certify that the premises are clean — a regulatory official must oversee the process, and the labor and materials are your financial responsibility.

Interstate Commerce Consequences

Beyond the direct penalties, a brucellosis violation can trigger movement restrictions that interrupt your ability to sell or transfer animals. Animals placed under quarantine cannot leave the premises except under specific regulatory conditions. If you attempt to move quarantined animals without authorization, you face additional violations on top of the original infraction.

Producers who operate across multiple species or property types should also be aware that Idaho’s regulatory framework extends to other areas of animal ownership. See brucellosis laws in Missouri for a comparison of how another state structures its penalty framework. For Idaho-specific rules on other animals, beekeeping laws in Idaho, leash laws in Idaho, and kennel zoning laws in Idaho are each governed by separate regulatory chapters with their own enforcement structures.

Summary of Key Violation Risks

The most effective way to avoid penalties is to treat vaccination, testing, and documentation as routine operational requirements rather than one-time events. The best way to prevent brucellosis from infecting your cattle herd is to ensure that your herd is 100% vaccinated, as required by state law, and do not allow any contact between wild elk and your cattle. Keeping wildlife separation as a management priority — particularly in and near the DSA — reduces your exposure risk before regulatory requirements even come into play.

For producers who manage diverse operations or want a broader view of Idaho’s animal law landscape, additional context is available through resources on rooster laws in Idaho, pit bull laws in Idaho, and roadkill laws in Idaho — each of which reflects how Idaho structures animal-related regulatory obligations across different contexts.