Bovine Tuberculosis Testing Requirements in Maryland: What Cattle Owners Must Know
August 25, 2026
Bovine tuberculosis testing requirements in Maryland exist because a single infected animal can trigger federal reclassification of the entire state’s herd status, closing off interstate markets for every cattle producer within its borders. Maryland has held Accredited Tuberculosis-Free status for years, but that designation depends on producers, veterinarians, and auction operators following a specific set of testing, movement, and reporting rules.
Whether you are moving cattle to a new farm, buying stock from out of state, or preparing animals for a county fair, understanding when a test is required and when it is not can save you time, money, and a call from the Maryland Department of Agriculture’s Animal Health Program. This guide breaks down the classification system, testing methods, movement rules, and quarantine procedures that apply to cattle owners across the state.
What Is Bovine Tuberculosis and Why It Is Regulated in Maryland
Mycobacterium bovis is the bacterium behind bovine tuberculosis, and it does not stay confined to cattle. Bovine tuberculosis is a rare disease that affects mammals, including cattle, deer, goats, dogs, and humans, caused by the bacteria Mycobacterium bovis. The disease spreads efficiently in confined herds, which is why regulators treat any detection as an emergency rather than a routine finding.
The disease is spread by direct contact, inhalation of droplets expelled from infected lungs, and ingestion of contaminated feed or milk. That transmission pathway is also why it poses a human health risk, historically through unpasteurized dairy products. Infected cattle are typically asymptomatic, which is precisely why testing rather than visual inspection forms the backbone of detection efforts.
The regulatory framework dates back over a century. In 1917, the U.S. Bureau of Animal Industry began the National Tuberculosis Eradication Program, which started out as strictly an eradication program for cattle but eventually included both bison and farmed cervids. Decades of coordinated testing have paid off dramatically: the prevalence of tuberculosis in cattle, bison, and captive cervids is extremely low in the United States, with an estimated prevalence of 7 per 1 million cattle screened. That success is fragile, though, and depends on states like Maryland maintaining consistent testing and reporting discipline.
Pro Tip: Because infected cattle rarely show symptoms, do not rely on herd observation alone. Annual veterinary checkups and compliance with import testing rules are the only reliable way to catch bovine TB before it spreads.
Maryland’s TB Classification Status and Risk Zones
Maryland’s regulatory status directly determines which of your cattle require testing. Maryland is a bovine tuberculosis free state and a bovine brucellosis free state, and the Maryland Department of Agriculture confirms Maryland is an Accredited Tuberculosis-Free State for cattle. That status places Maryland in USDA’s highest tier, alongside nearly every other state in the country.
Nationally, the picture is similarly strong but not perfect. Excepting four counties in Michigan comprising only 6,109 square kilometers, or 0.06% of US land area, classified as Modified Accredited, as of April 2022 the entire country was considered Accredited Free of bovine TB by the USDA for cattle and bison. That Michigan exception exists because free-ranging white-tailed deer act as a wildlife reservoir for the bacteria there, a risk factor Maryland producers should understand even though it does not currently apply within state lines. If you are curious about the broader wildlife disease landscape in the state, Maryland’s own bat populations carry their own set of health monitoring concerns worth a separate look at the types of bats in Maryland.
| State or Zone Status | Cattle/Bison Age Requiring Test | Program Position |
|---|---|---|
| Accredited-Free | 24 months and older | Highest tier; Maryland’s current status |
| Modified Accredited Advanced | 18 months and older | One step below Accredited-Free |
| Modified Accredited | 12 months and older | Indicates active disease management |
| Accreditation Preparatory | All ages | Lowest tier; most intensive testing |
In Accredited Free States or zones, testing covers all cattle or bison 24 months of age and older; in Modified Accredited Advanced zones it drops to 18 months; Modified Accredited zones test 12 months and older; and Accreditation Preparatory zones test cattle and bison regardless of age. Maryland’s Accredited-Free standing is why most in-state cattle move without routine TB testing.
Keeping that status is not automatic. To qualify for renewal of accredited-free State or zone status, a State must submit an annual report to APHIS certifying compliance with the Uniform Methods and Rules for Bovine Tuberculosis Eradication, submitted each year between October 1 and November 30. A single lapse in reporting or a cluster of infected herds can jeopardize that renewal, which is one reason Maryland’s animal health rules are enforced consistently rather than loosely.
Who Must Test and Which Animals Are Covered in Maryland
Not every cattle owner in Maryland needs to schedule a TB test. The obligation depends on how the animals are moved, sold, or exhibited. Registering the premises where you keep cattle protects your herd and others against the serious threat of a disease outbreak, and premises registration is required to get official identification for cattle. That registration step is the foundation everything else builds on.
Pro Tip: Register your farm premises with the Maryland Department of Agriculture before you need official eartags. Without a premises ID, you cannot obtain the identification required for interstate certificates or fair exhibitions.
For identification, Maryland recommends that all cattle producers use official identification, meaning eartags that carry a U.S. shield, for cattle identification. When it comes to testing scope, federal rules define a “whole herd test” precisely: an official tuberculin test of all cattle and bison in a herd that are 12 months of age or older, and of all cattle and bison less than 12 months of age that were not born into the herd, except those born in and originating from an accredited herd.
Maryland draws a clear line between simple farm transactions and commercial resale. Brucellosis and tuberculosis tests are not required for farm-to-farm sales, or for animals purchased by dealers from Maryland farms and sold to Maryland farms, except as otherwise noted. But once a dealer buys cattle for resale under different conditions, all herds shall have a complete negative tuberculosis test within the 12 months immediately preceding the sale.
Camelids get their own carve-out. A tuberculin test is not required for Maryland camelids, though out-of-state camelids face a different standard, covered in the movement section below. Owners managing multiple species on the same property should also review Maryland’s rabies vaccine requirements in Maryland, since overlapping animal health compliance is common on mixed livestock operations.
Approved TB Testing Methods in Maryland
Maryland follows the federally standardized testing protocol used nationwide rather than a separate state-specific test. The caudal-fold test is used as a presumptive diagnostic procedure, and animals classified as suspect must be evaluated further by the comparative cervical test, gamma interferon test, or sent directly to slaughter under permit. This two-tier approach exists because the initial screening test, while fast and inexpensive, is not specific enough to serve as a final diagnosis.
Understanding the biology helps explain the testing timeline. A tuberculin injection produces a delayed hypersensitivity reaction manifested by swelling and induration at the injection site if the animal has been exposed to bovine TB antigens, with a positive response usually beginning within 8 to 12 hours and peaking about 72 hours after injection. If the test produces any type of response, the veterinarian must immediately notify APHIS Veterinary Services Area Offices and State animal health officials.
Beyond the caudal-fold and comparative cervical tests, several supplemental diagnostic tools support confirmatory work. Histopathology, diagnostic bacteriology, and PCR assay of formalin-fixed tissue are all supplemental diagnostic procedures approved for use in the program, used in conjunction with tuberculosis test results and necropsy or slaughter data to assign herd status. Every test result must also be properly documented; all cattle and bison tested shall be individually identified by official eartags, with that identification recorded on the official test record at the time of injection and confirmed again at observation.
| Test | Purpose | Timing Note |
|---|---|---|
| Caudal-Fold Test (CFT) | Initial screening/presumptive | Read 72 hours post-injection |
| Comparative Cervical Test (CCT) | Confirmatory follow-up | Within 10 days of CFT, or wait 60 days |
| Gamma Interferon Assay | Confirmatory blood-based alternative | Requires State/APHIS approval to use |
| PCR, Culture, Histopathology | Supplemental lab diagnostics | Used with necropsy or slaughter data |
Interstate and Intrastate Movement Testing Requirements in Maryland
Movement within Maryland’s borders is generally simple. Cattle originating directly from herds not under restriction in Maryland may be moved to farms in Maryland without a tuberculosis test. That is the baseline most in-state producers rely on for routine sales and transfers.
Bringing cattle in from other states is where the rules require more attention. Cattle, bison, and goats may be imported into Maryland without testing provided they originate from herds in tuberculosis-free states. Beyond that, Maryland recognizes several additional paths to entry without a fresh test:
- From Tuberculosis Free Accredited herds, no test is required.
- From herds in which all animals tested negative within the past 12 months, no test is required, and progeny born since that test may be imported without a tuberculin test.
- Otherwise, a negative tuberculin test is required within 60 days prior to entry, with herd and area status shown on the certificate.
There is an important exception that overrides all of the above. Cattle that originate directly or indirectly from herds where infection with Mycobacterium bovis has been known to exist within the past 3 years may not be imported into the state, except for immediate slaughter. Even the slaughter exception comes with strict conditions: apparently healthy slaughter-type cattle may enter without a health certificate or TB test if consigned to a recognized public stockyard or an APHIS-approved slaughtering establishment, and must be slaughtered within 10 days of arrival unless the Department grants a special permit extension.
Auction markets carry their own biosecurity obligation regardless of test status. Cattle approved for entry into Maryland as free from tuberculosis or brucellosis may not be assembled, handled, or confined in any public stockyard, livestock auction, sales stable, or yard unless they are properly segregated in thoroughly cleaned, disinfected pens to prevent exposure to infected cattle or premises. Camelids follow a parallel structure: all camelids six months of age and over must either originate directly from an accredited herd or a TB-free state, or have a negative tuberculin test within 60 days of entry.
Fair and exhibition season adds one more layer. Because Maryland is an Accredited Tuberculosis-Free State, a tuberculin test is not required for Maryland cattle exhibited at fairs and shows, though RFID tags are now required for cattle and swine shown at Maryland exhibitions. Producers heading to fairs should also confirm their rabies vaccine requirements for dogs in Maryland if they bring working or companion animals along, since exhibition grounds often check multiple species’ health paperwork at once.
What Happens When a Suspect or Positive Result Occurs in Maryland
A single reactive test result triggers an immediate chain of reporting obligations. All accredited veterinarians must immediately report every suspected or diagnosed bovine TB case promptly to both the Assistant District Director and the State Animal Health Official. There is no discretion here; the report happens the moment a response is observed, not after confirmation.
Important Note: A suspect classification is not a diagnosis, but it does freeze certain movement rights until resolved. No cattle or bison responding to an official tuberculosis test are eligible for interstate movement unless subsequently classified negative for M. bovis through an official CCT test or gamma interferon assay, and federal regulation prohibits interstate movement of suspect cattle and negative herdmates in affected herds, except for slaughter, until the status of all suspects has been determined.
Confirmatory testing on suspect animals runs on a strict clock. Follow-up comparative cervical testing on a caudal-fold responder generally must occur within a narrow window after the initial injection, or the herd owner must observe a mandatory waiting period before a repeat test can be administered, and only Federal or State regulatory veterinarians who have had specialized training may conduct that follow-up testing. This is not a step producers can shortcut by asking a general practice veterinarian to re-test early.
Quarantine and Herd Depopulation Rules in Maryland
Once bovine TB is confirmed, the response scales well beyond the affected animal. Disclosure of tuberculosis in any herd triggers a complete epidemiologic investigation, and all cattle and bison in herds from which affected animals originated, as well as any animals known to have associated with them, shall be tested promptly. Every livestock herd within a 10-mile radius of the diagnosis will be tested within 6 months of that finding.
Producers facing a confirmed case have two management paths. Health officials manage tuberculosis in a herd either by depopulating the entire herd or by testing and removing individual reactor animals. There is no treatment option to fall back on, since tuberculosis is not treated in livestock.
Key Insight: Speed matters at the state level, not just the farm level. If an affected herd is depopulated and an epidemiologic investigation is completed within 90 days of detection with no evidence of spread, the state or zone may retain its accredited-free status. Miss that window, and everyone’s compliance burden increases.
Maryland’s Accredited-Free status is not permanently guaranteed even with fast depopulation. If two or more affected herds are detected in an accredited-free state or zone within a 48-month period, the state or zone will be removed from the list of accredited-free states or zones and reclassified as modified accredited advanced. That downgrade would mean every producer in the state suddenly faces testing requirements for younger cattle, as shown in the classification table above, which is why isolated cases are handled so aggressively.
Penalties for Non-Compliance in Maryland
Maryland’s authority to enforce testing and movement rules is not discretionary guidance; it is written into the same federal-state framework that governs eradication nationwide. State laws and regulations must be in place to provide the authority to apply tuberculosis tests to any livestock and to restrict the movement of any livestock or other animals, including captive wildlife suspected of being affected. Maryland has that authority in place through its Code of Maryland Regulations and the Agriculture Article.
All 50 states, including Maryland, participate in a program administered jointly with the federal government requiring testing, quarantine, and destruction of diseased animals, and many states have also enacted special legislation addressing the importation of cattle. In practical terms, that means:
- Moving cattle without required test documentation can result in quarantine of the animals and the receiving premises.
- Auction markets and dealers who fail to segregate untested or non-compliant cattle risk enforcement action against their facility license.
- Herds found to violate the 3-year infection-history import restriction face mandatory rejection or diversion to slaughter-only channels.
- Repeated violations that contribute to disease spread can trigger state-level reclassification, raising testing costs for every cattle owner in Maryland.
Because enforcement details and civil penalty schedules can be updated between regulatory cycles, producers should confirm current requirements directly with the Maryland Department of Agriculture’s Animal Health Program before moving, selling, or importing cattle. This article provides general regulatory information and is not a substitute for consulting a licensed accredited veterinarian or the state animal health official about a specific herd situation.
Staying compliant is less about memorizing every clause and more about knowing which category your situation falls into: in-state unrestricted movement, interstate import, dealer resale, or exhibition. For producers who also manage other regulated animals on the same property, checking related pages like rabies vaccine requirements for cats in Maryland, rabies vaccine requirements for ferrets in Maryland, or even recreational rules like hunting license requirements in Maryland and fishing license requirements in Maryland can help round out a farm’s full compliance picture.