Brucellosis Laws in Wisconsin: What Livestock Owners Need to Know

Wisconsin holds one of the most important designations in American livestock management — a Class Free brucellosis state — but that status comes with legal responsibilities that every cattle and bison owner in the state must understand. Brucellosis is a bacterial disease that can devastate a herd and spread to humans, making it one of the most tightly regulated animal diseases in the country.

Whether you raise a small beef herd, operate a dairy operation, or manage American bison, Wisconsin law imposes specific rules on testing, vaccination, movement, reporting, and quarantine. Violating those rules can result in forced slaughter of your animals, loss of indemnity payments, and civil or criminal penalties. This guide walks you through each layer of Wisconsin’s brucellosis regulatory framework so you know exactly what is required of you.

What Is Brucellosis and Why It Is Regulated in Wisconsin

Brucellosis is the contagious, infectious, and communicable disease caused by bacteria of the genus Brucella. It is also known as Bang’s disease, undulant fever, and contagious abortion, and it is transmissible to a variety of species including bovine animals, swine, cervids, and humans. That last point — human transmissibility — is a core reason why state and federal regulators treat the disease with particular seriousness.

The disease has significant consequences for animal health, public health, and international trade. Brucellosis occurs mainly in cattle, bison, and swine, but can affect other animals such as cervids, goats, sheep, and horses, as well as people. In cattle and bison, the bacteria of concern is Brucella abortus.

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, largely due to eradication efforts. Studies have shown that if brucellosis eradication program efforts were stopped, the costs of producing beef and milk would increase by an estimated $80 million annually in less than 10 years. That economic reality is precisely why Wisconsin enforces its brucellosis control program under Wis. Stat. § 95.26 and the companion administrative rules found in Wis. Admin. Code ATCP 10.

For Wisconsin cattle and bison producers, brucellosis regulation touches nearly every aspect of herd management — from how you vaccinate calves and identify animals to how you move them across county or state lines. Understanding the full picture is essential to staying compliant and protecting your herd’s health. You can also review Wisconsin’s pet import laws for additional context on how the state regulates animal movement broadly.

Wisconsin’s Brucellosis Classification Status

Wisconsin holds the highest possible disease classification under the federal brucellosis eradication framework. Under 9 CFR § 78.43, Wisconsin is listed among the validated brucellosis-free states, which means it has met the most rigorous standards set by the USDA Animal and Plant Health Inspection Service (APHIS).

For initial classification or reclassification as Class Free, all cattle herds in the state must have remained free of Brucella abortus for 12 consecutive months, based on surveillance and epidemiologic investigations, and the state must have a cattle herd infection rate of 0.0 percent, or 0 herds per 1,000. Wisconsin has maintained this status as part of a decades-long cooperative effort between state and federal animal health agencies.

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. 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. Wisconsin is geographically far from the Greater Yellowstone Area, which means it faces no active wildlife-related brucellosis pressure.

Class Free status matters practically for Wisconsin producers because restrictions on moving cattle and bison interstate become less stringent as a state approaches or achieves Class Free status. However, the state’s own statute makes clear that this status is not permanent by default. If the existence of brucellosis within the state results in the termination of its status as a certified brucellosis-free area by the U.S. Department of Agriculture, the department shall request the release of funds to pay for official vaccination of all female calves located within any county where the incidence of brucellosis disqualifies it for such designation.

Vaccination Requirements in Wisconsin

Because Wisconsin is a Class Free state, mandatory statewide calfhood vaccination programs are not currently in effect. However, the legal framework governing brucellosis vaccination remains active, and producers who choose to vaccinate — or who are directed to do so — must follow strict protocols under Wis. Stat. § 95.46 and ATCP 10.

No bovine animals may be vaccinated against brucellosis except calves within age ranges prescribed by department rules. Such calves may be vaccinated by approved veterinarians if officially reported to the department and permanently identified as official vaccinates as required under the statute and rules of the department.

Identification of vaccinated animals is a non-negotiable part of the process. All animals vaccinated by approved veterinarians shall be identified by a tattoo on the inner surface of the right ear of each animal, using such symbols as the department by rule prescribes. All veterinarians shall use only vaccine provided under federal regulations or produced by or under the direction or supervision of the department. They shall identify the vaccinates as required and record in triplicate on forms prepared by the department the information it requires. The veterinarian shall transmit one copy of the vaccination record to the department within 15 days after the date of vaccination.

At the federal level, the vaccination standards are equally specific. An official calfhood vaccinate is a female cattle or female bison vaccinated while from 4 through 12 months of age by an APHIS representative, state representative, or accredited veterinarian with a reduced dose approved brucella vaccine, and permanently identified by a tattoo and by an official vaccination eartag in the right ear.

• Only approved veterinarians may administer brucellosis vaccines to bovine animals in Wisconsin
• Vaccination is restricted to calves within age ranges set by DATCP rules
• A right-ear tattoo and official vaccination eartag are required for every vaccinate
• Vaccination records must be submitted to DATCP within 15 days of the vaccination date
• Only USDA-approved or department-supervised vaccines may be used

Testing Requirements for Cattle and Bison in Wisconsin

Wisconsin’s Class Free status has significantly reduced routine testing obligations for in-state herds, but testing requirements are far from eliminated. The Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) retains broad authority to test, classify, and act on results at any time.

Upon receiving a brucellosis test result, the department or the federal bureau shall classify the tested animal as negative, suspect, or reactor, according to the brucellosis uniform methods and rules. The department or the federal bureau may use supplemental brucellosis tests to confirm test results and to evaluate whether animals may be infected with brucellosis.

For cattle that test as reactors, the consequences are immediate and mandatory. Cattle and American bison that are classified as reactors to the brucellosis test, whether or not conducted pursuant to this section, shall be slaughtered. A report of any test disclosing reactors shall be mailed to the owner thereof. The reactors shall be identified by a reactor tag and permanent mark as prescribed by the department.

The owner shall effect slaughter of the reactors within 15 days of the date they are so identified, except that the department, for cause shown, may extend the time. No indemnity shall be paid on any reactors disposed of by the department. No milk shall be sold from any reactors or from any herd of cattle in which reactors are kept contrary to the provisions of this section.

DATCP also holds authority to test other species beyond cattle and bison. The department may obtain blood or tissue samples from swine and farm-raised deer to test for brucellosis, and may condemn swine and farm-raised deer that are reactors to the brucellosis test and may quarantine the herd from which the reactors come.

Herd certification as brucellosis-free is available to cattle, farm-raised deer, and goat operations. A certified brucellosis-free herd means a herd of cattle, farm-raised deer, or goats that is certified as brucellosis-free by the department under Wis. Admin. Code ATCP 10.12, 10.51, or 10.73. The department may certify a herd of cattle as a brucellosis-free herd if the herd qualifies for that certification under the brucellosis uniform methods and rules. This certification can be a significant advantage when moving animals or selling breeding stock. You can compare Wisconsin’s approach with how neighboring states handle similar requirements by reviewing brucellosis laws in Minnesota and brucellosis laws in Michigan.

Interstate and Intrastate Movement Rules in Wisconsin

Movement rules are where Wisconsin’s brucellosis regulations have the most day-to-day impact on producers. The rules differ depending on whether you are moving animals within Wisconsin or bringing them in from another state.

Moving cattle within Wisconsin: Cattle from within Wisconsin have no requirements for tests or health documents for purposes such as attending fairs and shows. This reflects the state’s Class Free status and the low disease risk within the state. However, this general exemption does not override quarantine orders or special movement restrictions that DATCP may impose during a disease event.

Importing cattle from other states: Cattle from outside Wisconsin must be accompanied by a certificate of veterinary inspection (CVI or health certificate) documenting official animal identification and all required tests and certifications, and must meet all of Wisconsin’s normal requirements for import. Acceptable forms of official ID for imported cattle include USDA metal ear tags under the National Uniform Eartagging System and 15-digit “840” tags (visual or RFID).

No cattle from outside Wisconsin are currently required to be brucellosis tested or vaccinated to come to fairs and shows in Wisconsin. That said, this applies specifically to show and fair contexts; routine import requirements for breeding stock and commercial cattle may differ based on the origin state’s disease status and DATCP’s current import rules under ATCP 10.22.

For animals already under quarantine, the rules are absolute. No cattle or American bison subject to quarantine shall be removed from the premises where they are quarantined, except upon written permit of the department. The quarantine shall remain in full force until removed by the department.

Wisconsin also has emergency movement authority. The department may promulgate emergency rules upon the outbreak in this state of brucellosis to prevent the movement and sale of cattle unaccompanied by reports of complete negative brucellosis tests. This provision allows DATCP to act quickly if the state’s Class Free status is ever threatened. For context on how neighboring states handle similar movement rules, see brucellosis laws in Nebraska and brucellosis laws in Missouri.

Reporting and Quarantine Requirements in Wisconsin

Wisconsin’s brucellosis reporting and quarantine system is designed to contain any potential outbreak rapidly and prevent disease spread to neighboring herds. Both the state and federal governments play roles in this process, with DATCP serving as the primary state authority under Wis. Stat. § 95.26 and ATCP 10.

When a brucellosis reactor is identified in a herd of cattle or American bison, quarantine is the immediate response. When reactors to any brucellosis test are disclosed in a herd of cattle or American bison, the department shall quarantine the entire herd by serving written notice thereof, either personally or by mail, on the owner or person in charge, but such quarantine shall not be imposed if the department, upon the basis of the clinical history of the herd with respect to brucellosis and the recommendation of the attending veterinarian, determines it is improbable that the cattle or American bison will contract brucellosis.

The quarantine is not lifted automatically once reactors are removed. Such retests shall be conducted as the department finds necessary to eliminate all reactors or other evidence of infection in the herd. In practice, this means your herd may remain under quarantine through multiple rounds of testing until the department is satisfied that no further infection is present.

DATCP also has the authority to act on animals that have not yet tested positive but are suspected of exposure. With the consent of the owner, the department may condemn, in infected herds, animals which have been exposed and which are suspected of being infected, although the animals have not reacted to the brucellosis tests.

The reporting obligation flows both ways. When a test discloses reactors, a report of any test disclosing reactors shall be mailed to the owner thereof. At the same time, veterinarians who conduct brucellosis tests are required to maintain official records and report results to the department. Any accredited veterinarian who tests an animal for brucellosis must insert an official eartag in the right ear of the animal unless the animal already carries official identification.

1. Reactor identified through official brucellosis test
2. Department notifies owner by mail or personal service
3. Reactor tagged and permanently marked per department prescription
4. Owner must arrange slaughter within 15 days of identification
5. Entire herd placed under written quarantine notice
6. No animals may leave the premises without a written department permit
7. Retesting continues until all reactors and evidence of infection are eliminated
8. Department removes quarantine upon satisfactory clearance

Wisconsin livestock owners should also be aware of how brucellosis intersects with other animal health and movement laws. Reviewing goat ownership laws in Wisconsin is helpful if you keep goats alongside cattle, as goats are also subject to brucellosis certification rules under ATCP 10. Similarly, producers who keep farm-raised deer should note that DATCP has independent brucellosis testing authority over those animals as well.

Penalties for Brucellosis Violations in Wisconsin

Wisconsin’s penalty structure for brucellosis violations operates on multiple levels — loss of indemnity, forced slaughter at the owner’s expense, civil forfeitures, and potential criminal liability under the broader animal health statutes in Chapter 95.

Loss of indemnity payments: One of the most significant financial consequences of non-compliance is the forfeiture of state indemnity. No indemnity shall be paid on any reactors disposed of by the department — meaning if DATCP has to step in and remove animals because you failed to act, you lose any compensation. By contrast, for each animal of a species raised primarily to produce food for human consumption, including farm-raised deer, condemned and slaughtered, the owner shall receive and, upon certificate of the department, the state shall pay two-thirds of the difference between the net salvage value and the appraised value of the animal, but the payment may not exceed $1,500 for an animal — but only when the owner complies with the process voluntarily.

Milk sale prohibition: No milk shall be sold from any reactors or from any herd of cattle in which reactors are kept contrary to the provisions of this section. For dairy operations, this can represent an immediate and substantial economic loss while the herd remains under quarantine.

Failure to slaughter reactors: If the owner of reactors fails to comply with the slaughter requirement within the time limited, the department shall cause the removal and slaughter of the reactors. When the department takes that action, the owner loses indemnity entirely and may also face the costs associated with the department’s removal and disposal activities.

Unauthorized movement violations: Moving quarantined cattle or bison without a written department permit violates Wis. Stat. § 95.26(5) directly. Wisconsin’s Chapter 95 animal health statutes authorize civil and criminal enforcement actions for violations of disease control requirements. DATCP promulgates administrative rules pursuant to rulemaking authority conferred by the Legislature, and those administrative rules have the force and effect of law and become part of the Wisconsin Administrative Code. Violations of those rules carry the same legal weight as violations of the underlying statutes.

It is worth noting that Wisconsin’s penalty framework is largely structured around compliance incentives rather than punitive fines as a first response. The loss of indemnity — potentially thousands of dollars per animal — is itself a powerful deterrent. Producers who cooperate fully with DATCP, slaughter reactors on time, and comply with quarantine orders preserve their right to state compensation. Those who do not lose that protection entirely.

For a broader view of how Wisconsin regulates animals and livestock, you may find it useful to explore related topics such as beekeeping laws in Wisconsin, kennel zoning laws in Wisconsin, and emotional support animal laws in Wisconsin. For brucellosis rules in nearby states, see brucellosis laws in Nevada for a western state comparison.

Conclusion

Wisconsin’s brucellosis laws reflect a carefully maintained balance between protecting the state’s Class Free status and holding livestock owners accountable for their role in disease prevention. As a cattle or bison producer in Wisconsin, your key obligations are straightforward: vaccinate calves only through approved veterinarians and report those vaccinations promptly, comply with all testing requirements and reactor disposal timelines, never move quarantined animals without a written department permit, and report any suspected disease activity to DATCP immediately.

The state’s indemnity program rewards producers who follow the rules, paying up to two-thirds of the difference between an animal’s net salvage and appraised value when you cooperate with condemnation and slaughter orders. Non-compliance eliminates that financial protection entirely and can expose you to further civil or criminal liability under Chapter 95. Staying current with DATCP guidance, working with an accredited veterinarian, and maintaining thorough herd records are the most effective ways to protect both your animals and your operation under Wisconsin’s brucellosis regulatory framework.

For additional context on Wisconsin animal law, see related guides on roadkill laws in Wisconsin, dog bite laws in Wisconsin, leash laws in Wisconsin, and pet custody laws in Wisconsin.