Bovine Tuberculosis Testing Requirements in Michigan: Zones, Methods, and Movement Rules Explained
August 12, 2026
If you own cattle or bison anywhere near Michigan’s northeastern Lower Peninsula, the bovine tuberculosis testing requirements in Michigan are not optional paperwork you can skip. They are a legal condition of keeping and moving your herd, backed by state law and enforced through mandatory whole-herd testing, movement certificates, and quarantine orders.
Michigan is one of the few states still fighting an active reservoir of bovine TB in its wild deer population, and 2026 has already brought new detections in Alpena, Presque Isle, and Iosco counties, plus proposed testing expansions into five more counties. Below, you’ll find the current classification zones, who has to test, which methods are approved, and what happens if a herd comes back positive.
What Is Bovine Tuberculosis and Why It Is Regulated in Michigan
Bovine tuberculosis is caused by Mycobacterium bovis, an organism closely related to the organism that causes avian TB (Mycobacterium avium), human TB (Mycobacterium tuberculosis), and Johne’s disease. In Michigan’s case, the regulatory concern isn’t just cattle-to-cattle spread. Bovine TB is a bacterial disease that can affect all mammals, including humans, and is known to be present in the wild white-tailed deer population in specific areas of northeastern lower Michigan, where it can be transmitted between deer and cattle.
That wildlife reservoir is what separates Michigan from most other states, where bovine TB has been effectively eliminated from cattle herds. As of a January 2026 legislative update, the program is of high visibility and interest to farmers, Michigan’s 12,200 cattle producers and their 1.2 million cattle, hunters, and the federal government. The stakes go beyond animal health: other states would close their markets to Michigan cattle, meat, and milk products if the program was reduced or eliminated.
For a broader look at how mycobacterial diseases affect different animal groups in the state, the avian tuberculosis guide and general bovine disease overview cover related conditions that sometimes complicate TB test results.
Michigan’s TB Classification Status and Risk Zones
Michigan’s bovine TB program runs on a zone system. There are currently two bovine TB zones within the state: a four-county area (Alcona, Alpena, Montmorency, and Oscoda counties) known as the Modified Accredited Zone (MAZ) and the remainder of the state known as the Accredited Free Zone. Presque Isle County is part of the Accredited Free Zone, but the county has many of the same requirements for bovine TB testing and movement of cattle as the MAZ.
Beyond those core areas, due to their proximity to the MAZ, there are additional requirements in Presque Isle, Cheboygan, Crawford, Iosco, Ogemaw, Otsego, and Roscommon counties. This buffer approach exists because the disease doesn’t respect county lines the way regulations do. Michigan’s history with TB zoning is also a cautionary tale: in 2000, the entire state of Michigan dropped status from Accredited Free to Modified Accredited, which greatly affected Michigan’s cattle industry.
| Zone or Area | Counties Covered | Testing Requirement | Special Rules |
|---|---|---|---|
| Modified Accredited Zone (MAZ) | Alcona, Alpena, Montmorency, Oscoda | Annual whole-herd surveillance testing | Mandatory RFID, movement certificates, wildlife biosecurity |
| Presque Isle County | Presque Isle | MAZ-equivalent testing practices | Same ID and movement rules as MAZ despite Accredited Free status |
| Additional buffer counties | Cheboygan, Crawford, Iosco, Ogemaw, Otsego, Roscommon | Enhanced monitoring near MAZ | Extra biosecurity and reporting provisions |
| Proposed new testing areas (2026) | Portions of Antrim, Arenac, Charlevoix, Iosco, Ogemaw | Whole-herd test required by July 21, 2027 | Covers animals 12+ months and any age not born on the farm |
| Accredited Free Zone (rest of state) | All other Michigan counties | No mandatory routine testing | Subject to reclassification after new detections |
That last row is more than theoretical. Proposed orders would require all cattle and bison herds located in designated township sections of Antrim, Arenac, Charlevoix, Iosco and Ogemaw counties to be tested for bovine TB by July 21, 2027, including all cattle and bison 12 months of age or older and cattle and bison of any age that were not born on the farm. MDARD is proposing the new testing requirements due to the detection of bovine TB in cattle herds from Charlevoix and Iosco counties earlier this year.
Important Note: The 2026 proposed orders for Antrim, Arenac, Charlevoix, Iosco, and Ogemaw counties were still moving through public comment as of mid-2026. Confirm current status directly with MDARD before assuming your township is or isn’t covered.
Since these counties are not within Michigan’s existing bovine TB testing area, Public Act 466 of 1988 authorizes MDARD to implement orders for testing animals for bovine TB and other reportable diseases. That same statute is the legal backbone for every enforcement action discussed later in this guide. If you split time between livestock and outdoor recreation in the affected region, it’s worth knowing that deer density management ties directly into TB control, which is one reason hunting license requirements in Michigan intersect with the state’s disease strategy in these counties.
Who Must Test and Which Animals Are Covered in Michigan
Testing obligations in Michigan depend on where your herd is physically located, not on breed or production type. Coverage is broad by design: the references to “bison and cattle” in the program language include all bovine (genus Bos) animals, bovine-like animals (genus Bison, also commonly referred to as American buffalo or bison), and any cross of these animals.
In practical terms, you’re on the hook for testing if you fall into one of these categories:
- You run a commercial cattle or bison herd anywhere inside the MAZ (Alcona, Alpena, Montmorency, Oscoda).
- You own cattle or bison in Presque Isle County, which mirrors MAZ testing expectations.
- Your property sits inside one of the proposed 2026 testing townships in Antrim, Arenac, Charlevoix, Iosco, or Ogemaw counties.
- You plan to exhibit bison or cattle imported from out of state, which triggers identification and CVI requirements regardless of zone.
- You’re importing animals into Michigan from a state or area that isn’t officially TB accredited free.
Age matters for the newer orders specifically: testing would include all cattle and bison 12 months of age or older and cattle and bison of any age that were not born on the farm. That second clause closes an obvious loophole, since a young animal bought in from an untested herd could otherwise slip through screening based on age alone.
Michigan handles several other mandatory animal-health tests the same way, requiring compliance based on species and location rather than owner preference. If you also own horses, the EIA Coggins test requirements in Michigan follow a similar location-based logic, and dog and cat owners face comparable statewide mandates under the rabies vaccine requirements for dogs in Michigan and rabies vaccine requirements for cats in Michigan.
Approved TB Testing Methods in Michigan
Michigan follows the federal testing hierarchy set out in USDA’s Uniform Methods and Rules, and the official tuberculin tests for cattle, bison, and goats are the caudal-fold test, the comparative cervical test, and the cervical test. In routine practice, this plays out in a specific sequence.
- Caudal fold test (CFT): An accredited veterinarian injects tuberculin into the skin fold at the base of the tail and reads the response roughly 72 hours later.
- Same-day notification: Any suspect response must be reported to MDARD immediately, since the follow-up window is tight.
- Comparative cervical test (CCT): This is currently the only accepted follow-up test in Michigan.
- Laboratory analysis: Reactor animals are removed and examined, with tissue samples sent for confirmatory testing.
- Herd classification: The herd is cleared, retested, or classified as affected based on results.
Michigan lost one of its confirmatory testing options several years ago: since May 26, 2017, the U.S. Department of Agriculture suspended the approval of the bovine tuberculosis gamma interferon test, and the only other test approved for follow-up testing of bovine TB caudal fold suspect animals is the comparative cervical test (CCT), which can only be performed by MDARD or USDA veterinarians. The CCT is similar to the Caudal Fold test as it involves an initial injection and then the test is read three days later.
Pro Tip: Timing is unforgiving on follow-up testing. Notify MDARD the same day you spot a caudal fold suspect, since the CCT window is only a matter of days before your herd faces a much longer quarantine.
The CCT must be started within seven days of the day you read a caudal fold test, and if the test is not started within this seven-day period, the herd must remain under quarantine until the next approved testing period, which would be no sooner than 60 days. Producers and veterinarians testing in the northern counties have a dedicated contact point: if you are testing in Alcona, Alpena, Antrim, Charlevoix, Cheboygan, Crawford, Emmet, Iosco, Montmorency, Ogemaw, Oscoda, Otsego, or Presque Isle or Roscommon counties, please direct all communications to MDARD’s Atlanta office. For a full technical rundown of the caudal fold and comparative cervical procedures, the USDA APHIS tuberculosis reference guide covers the federal standards Michigan follows.
Interstate and Intrastate Movement Testing Requirements in Michigan
Moving cattle or bison across Michigan’s border, or even between counties within the state, triggers its own set of rules separate from herd surveillance testing. For incoming animals, the state keeps things simple when the origin is already TB-free: there are no bovine tuberculosis (TB) testing requirements for bison or cattle being imported into Michigan from states or areas that are officially designated as tuberculosis accredited free. Importing from a non-free area is a different story entirely, and MDARD wants advance notice: if you are interested in bringing bison or cattle into Michigan from states or areas that do not have tuberculosis accredited free status, please contact MDARD at 800-292-3939 prior to entry.
Not every class of animal carries the same risk profile for interstate movement. Non-lactating dairy cattle, including heifers, dry cows, and bull calves, are not currently subject to testing for interstate movement due to their risk profile. Once animals are ready to leave a Michigan premises, identification becomes mandatory regardless of testing status: bison and cattle regardless of age, sex, or breed must be tagged with official Radio Frequency Identification (RFID) ear tags before they leave a Michigan premises.
Movement inside the state carries extra weight in high-risk counties. In Presque Isle County, as well as in the bovine tuberculosis (TB) Modified Accredited Zone (MAZ), which consists of Alcona, Alpena, Montmorency, and Oscoda counties, there are additional requirements for identification and movement of bison or cattle. Exhibition animals face their own checklist too: bison and cattle being imported from out-of-state for exhibition must have a completed interstate certificate of veterinary inspection meeting import requirements, plus official identification.
Movement rules for livestock in Michigan aren’t limited to bovine TB. If you’re coordinating transport, boarding, or interstate travel with other animals, the rabies vaccine requirements in Michigan page outlines a parallel set of documentation rules that often come up during the same paperwork process. For the official movement page covering current bison and cattle rules directly from the source, see MDARD’s bison and cattle import page.
What Happens When a Suspect or Positive Result Occurs in Michigan
Suspect results trigger a fast-moving process, and 2026 has already provided two real examples of how it plays out. In April, MDARD reported the detection of bovine tuberculosis in two cattle herds from Alpena and Presque Isle counties, with the cases detected during the annual whole-herd surveillance tests for each herd. An investigation followed immediately: an epidemiological investigation was performed to identify the possible sources of infection and included genetic analysis of the specific tuberculosis organism found.
A month later, a different detection pathway surfaced a case in Iosco County. Following a bovine TB detection in an adult cow identified at a USDA Food Safety Inspection Service-inspected processing plant, the animal was traced back to the Iosco County herd, which was subsequently tested, and additional bovine TB cases were found. That case shows testing doesn’t only happen on the farm; slaughter-plant inspection is its own layer of the surveillance net, and a positive there triggers the same traceback and herd-testing obligations.
State Veterinarian Nora Wineland has repeatedly tied these cases back to the same root cause. Her office noted both herds “illustrate why it is so crucial to consistently perform surveillance testing and actively manage this disease.” Once a suspect or reactor is confirmed, the herd moves into quarantine, covered in the next section.
Quarantine and Herd Depopulation Rules in Michigan
A confirmed suspect doesn’t automatically mean depopulation. Michigan’s own recent case files show that a well-managed quarantine can end with a clean herd. According to a January 2026 legislative update, one herd’s two negative whole herd tests were followed by a third test that identified one adult cow that responded and had lesions suggestive of bovine TB upon examination at the Michigan State University Veterinary Diagnostic Laboratory, with samples then confirmed as compatible for bovine TB by USDA’s National Veterinary Services Laboratory. Rather than moving straight to depopulation, MDARD worked with the herd owner to schedule additional testing, and all animals were negative on a subsequent whole herd test, which was completed on December 5, 2025.
That outcome reflects the two paths available to an affected herd owner under the federal framework Michigan follows: whole-herd depopulation, or a structured test-and-removal plan where reactors are pulled individually and the remaining herd is retested at intervals until it clears. Which path makes sense depends on herd size, infection spread, and how quickly retesting can confirm the herd is clean.
Quarantine risk in the highest-exposure counties doesn’t end once a herd clears testing, because the wildlife reservoir keeps reintroducing risk. MDARD’s response has been to build prevention into the landscape itself: the TB Program, in conjunction with the TB Advisory Committee, developed an Enhanced Wildlife Biosecurity (EWB) Program to assist farmers with protection of their herds, and producers can participate in a 90% State / 10% producer cost-share program to construct fences and protect feed storage facilities.
Important Note: Enhanced Wildlife Biosecurity verification isn’t optional for larger operations in the highest-risk areas, and disease control permits used to remove deer near farms are handled separately from normal hunting season rules, as detailed by MSU Extension’s disease control permit guidance.
Penalties for Non-Compliance in Michigan
Every testing order, movement rule, and quarantine described above rests on the same legal foundation. Since affected counties are not within Michigan’s existing bovine TB testing area, Public Act 466 of 1988 authorizes MDARD to implement orders for testing animals for bovine TB and other reportable diseases. That statute gives MDARD the standing to issue binding testing orders, not just recommendations, which is why producers in newly designated townships receive formal letters rather than informational mailers.
The most immediate consequence of skipping or delaying required testing is an extended quarantine. As already noted, if a CCT follow-up test is not started within the seven-day window, the herd must remain under quarantine until the next approved testing period, which would be no sooner than 60 days. That’s a minimum two-month restriction on herd movement and sales triggered simply by a missed window, before any actual infection is even confirmed.
The broader risk runs beyond any single herd. Because Michigan’s federal accreditation depends on program integrity, other states would close their markets to Michigan cattle, meat, and milk products if the program was reduced or eliminated, meaning that widespread non-compliance doesn’t just penalize individual owners; it can jeopardize sale eligibility for every cattle and dairy producer in the state. Veterinarians carry their own compliance obligation too, since failing to report a completed tuberculin test is grounds for losing federal accreditation status under the national program that governs who can legally administer these tests.
MDARD continues to lean on outreach alongside enforcement, holding regular coordination sessions such as the Herd and Hunter meeting planned for Presque Isle County to keep producers and hunters aligned on shared responsibility. If you’re a herd owner in or near an affected county, the practical takeaway is straightforward: test on schedule, report suspects the same day you find them, and keep your RFID and movement paperwork current, because the cost of falling behind compounds fast under Michigan’s bovine TB program.