Bovine Tuberculosis Testing Requirements in Illinois: What Cattle Producers Must Know

Illinois cattle producers rarely see a positive bovine tuberculosis test, and that is exactly the point of the rules that govern the disease. Bovine tuberculosis testing requirements in Illinois exist because the state’s clean status depends on constant verification, not luck, and a single lapse in documentation can trigger a quarantine that shuts down sales, shows, and interstate shipments. Whether you raise a handful of breeding cows or manage a commercial dairy herd, understanding when testing applies, which animals are covered, and what happens after a suspect result keeps your operation compliant and your herd moving.

This breakdown walks through Illinois’s tuberculosis classification, who must test, the approved testing methods accredited veterinarians use, and the quarantine, depopulation, and penalty provisions written into state law.

Important Note: This article summarizes state and federal regulations for general informational purposes. Confirm current requirements with the Illinois Department of Agriculture or an accredited veterinarian before moving, testing, or exhibiting animals, since program status and rules can change.

What Is Bovine Tuberculosis and Why It Is Regulated in Illinois

Bovine tuberculosis is caused by Mycobacterium bovis, a bacterium that produces a contagious, infectious, communicable disease of animals and humans that is commonly chronic and debilitating but can occasionally become acute and rapidly progressive. It qualifies as a serious animal health threat because it is a widespread zoonosis affecting nearly all vertebrate species and spreads through direct contact, inhalation of respiratory droplets, and ingestion of contaminated feed or milk.

The federal response dates back further than most producers realize. The U.S. Bureau of Animal Industry began the National Tuberculosis Eradication Program in 1917 out of concern for human and livestock health, and the effort started as a cattle-only program before eventually including bison and farmed cervids. Decades of testing paid off: the prevalence of tuberculosis in U.S. cattle, bison, and captive cervids is now extremely low, at an estimated 7 cases per 1 million cattle screened.

Illinois enforces its share of that eradication program through the Illinois Bovidae and Cervidae Tuberculosis Eradication Act, the state law that gives the Illinois Department of Agriculture authority to require testing, issue quarantines, and order depopulation when necessary. Testing requirements work alongside broader herd health practices covered in Illinois livestock biosecurity requirements, and TB sits among several reportable conditions tracked under the state’s bovine disease surveillance programs.

Illinois’s TB Classification Status and Risk Zones

Illinois is an Accredited Tuberculosis-Free State, which means a tuberculin test is not required for Illinois cervidae moving within state lines. That designation is not permanent or automatic. Federal rules classify states and zones on a sliding scale based on disease prevalence, and Illinois has to keep earning its top tier every year.

The federal framework defines four tiers, from least to most restrictive:

Classification	Prevalence Threshold	Practical Effect
Accredited-Free	Zero percent, meaning no finding of tuberculosis in any cattle, bison, or goat herd in the state or zone	Cattle or bison may move interstate without further TB testing restrictions
Modified Accredited	Tuberculosis prevalent in less than 0.1 percent of captive cervid herds in the state	Additional herd testing and movement documentation required
Accreditation Preparatory	Tuberculosis prevalent in less than 0.5 percent of cattle and bison herds in the state or zone	Whole-herd testing and stricter entry requirements apply
Non-Accredited	Prevalence exceeds preparatory thresholds	Full herd test plus individual pre-entry testing required for animals entering Illinois

To keep its accredited-free rating, Illinois must submit an annual report to APHIS certifying compliance with the Uniform Methods and Rules for Bovine Tuberculosis Eradication, filed each year between October 1 and November 30. That annual certification is why the classification status matters for every producer moving stock: a downgrade would immediately add testing burdens that do not currently apply to in-state movement.

Pro Tip: Before purchasing cattle from another state, ask the seller whether that state carries Accredited-Free status. Cattle from a non-accredited state or zone trigger herd and individual testing requirements that accredited-free cattle skip entirely.

Who Must Test and Which Animals Are Covered in Illinois

The Illinois Bovidae and Cervidae Tuberculosis Eradication Act casts a wide net over species. Under the Act, all owners of dairy or breeding cattle, bison, sheep, goats, antelope, or cervids within Illinois must submit their animals for tuberculin testing as required. The statute defines these covered groups precisely:

• Cattle — any member of the family bovidae of the genus bos, including exotic types of cattle and oxen
• Bison — any member of the genus bison, including buffalo, exotic buffalo types, and crossbred bison such as beefalo and cattalo
• Sheep and goats — any member of the family bovidae of the subfamily Caprinae, covering all domestic and wild members of the subfamily
• Antelope — any member of the family bovidae of the subfamily Antilopinae
• Cervidae — any member of the family cervidae, including domestic deer, moose, and elk maintained in captivity

Age thresholds also determine who tests. Federal rules define a whole herd test as an official tuberculin test of all cattle and bison 12 months of age or older, plus any younger animals not born into the herd, so calves born and raised on-site are typically exempt from routine herd testing. Exhibition animals face separate scrutiny: cattle entering Illinois for exhibition from states with a high incidence of tuberculosis must test negative for the disease, and deer and elk transported into the state must test negative for tuberculosis prior to entry to prevent spillover from captive cervids to livestock.

Approved TB Testing Methods in Illinois

Illinois relies on the same federally recognized testing sequence used nationwide, performed with tuberculin obtained through the state animal health official. Diagnosing TB in live animals depends on an effective testing technique using an intradermal injection of tuberculin obtained through the USDA, and only bovine purified protein derivative tuberculin, or PPD bovis, licensed by USDA is acceptable for official testing.

The testing sequence generally follows these steps:

1. Caudal Fold Test (CFT): A small amount of PPD tuberculin is injected into the tail fold, and the site is read 72 hours (plus or minus 6 hours) later. A negative result requires no further action, while a positive result classifies the animal as a responder needing further testing.
2. Interpreting the reaction: A true positive response usually begins within 8 to 12 hours after injection and peaks around 72 hours later.
3. Secondary testing: Responders move to the comparative cervical test, the gamma interferon test, or are sent directly to slaughter under permit, with follow-up testing limited to specially trained federal or state regulatory veterinarians.
4. Gamma interferon alternative: This whole-blood test must be performed within three to thirty days following the initial CFT injection and offers a faster confirmatory path than waiting for a second skin test.
5. Documentation: Results are recorded on VS Form 6-22, the Tuberculosis Test Record, with every tested animal identified by official eartag.

Illinois recognizes three official TB tests for cattle and bison — the CFT, the cervical test, and the comparative cervical test — plus the interferon gamma assay, which is an official test for cattle only. Cervidae follow a species-specific protocol: accredited free-area cervidae must test negative to two single cervical tests using 0.1 PPD Bovis tuberculin, read at 72 hours plus or minus 6 hours, no less than 90 days apart, or as an alternative, negative to two USDA official blood tests conducted no less than 30 days apart.

Key Insight: False positives are expected, not a sign of poor technique. Animals exposed to related bacteria such as avian TB, Johne’s disease, human TB, or soil mycobacteria may also respond to the CFT, producing false positives in roughly 1 to 5 percent of tested cattle. Reviewing the differences between mammalian and avian tuberculosis helps explain why a single skin-test response is never treated as a confirmed diagnosis.

Interstate and Intrastate Movement Testing Requirements in Illinois

Movement testing depends almost entirely on where an animal is coming from. Cattle from an accredited-free state have no additional testing requirements beyond a current certificate of veterinary inspection, and all cattle, including steers, originating from an Accredited Tuberculosis Free State may enter Illinois for exhibition when accompanied by a CVI issued within 30 days.

Animals coming from non-accredited areas face a heavier documentation burden. Entry rules require that the certificate of veterinary inspection show a complete negative herd test conducted within the past 12 months, plus an individual negative tuberculin test conducted within 30 days prior to entry. Breeding cattle face an even more layered standard: they must be individually identified by ear tag, tattoo, or registration number, and originate from a herd with a negative herd test within the past 12 months, backed by either one individual tuberculin test within 30 days of entry or two additional tests conducted within 180 and 30 days prior to entry.

Exhibition animals that stay in Illinois carry follow-up obligations. Cattle that enter for exhibition and do not return to their state of origin within 30 days must be isolated and retested for TB 60 to 120 days later. Goats face parallel rules: those from non-accredited states must show a complete negative herd test within the past 12 months and an individual negative tuberculin test within 30 days of entry. Captive cervidae have their own path — cervidae from an accredited herd may move into Illinois without further testing if accompanied by a certificate confirming accredited-herd origin, while those from non-accredited herds need a complete herd test within the past year plus two negative blood or single cervical tests conducted within 180 and 30 days prior to entry.

Producers moving animals should also secure the right paperwork before the trailer leaves the farm. Out-of-state entries typically require an animal import permit obtained through the Department’s online Animal Import Permit System, and vehicles hauling livestock across state lines should meet the standards outlined in Illinois livestock trailer requirements. Horse owners face a similarly structured system for a different disease under the EIA Coggins test requirements in Illinois, which follows the same logic of herd-of-origin documentation and pre-entry test windows.

What Happens When a Suspect or Positive Result Occurs in Illinois

A suspect classification does not mean an animal is infected — it means more testing is coming. Illinois law defines a tuberculosis suspect as any covered animal that shows a response to a caudal fold or single cervical tuberculin test without yet being classified a reactor, or that has been classified a suspect by a comparative cervical test.

Federal protocol requires immediate reporting: if the test produces any type of response, the testing veterinarian must immediately notify APHIS Veterinary Services and state animal health officials, and accredited veterinarians must report every suspected or diagnosed bovine TB case promptly to both the Assistant District Director and the State Animal Health Official. From there, outcomes split three ways: a negative secondary test requires no further action, while a confirmed reactor is humanely euthanized for necropsy and diagnostic testing. A suspect animal either goes for necropsy immediately or remains under quarantine for a second comparative cervical test after 60 days, and if that second test is still positive, the animal is euthanized and sent for laboratory confirmation.

Illinois adds a distinctive identification step for confirmed reactors. Any animal that reacts to the tuberculin test must immediately be branded on the left hip with a letter “T” not less than two nor more than three inches in length, and tagged in the left ear with a special Department-issued tag. The testing veterinarian is responsible for notifying the Department of Agriculture of any reactor and for applying the brand and tag, and no person may remove that identification tag once applied.

Quarantine and Herd Depopulation Rules in Illinois

Suspicion of infection triggers an immediate, whole-herd response. Illinois regulations state that herds or flocks suspected of bovine tuberculosis infection must immediately be quarantined and the entire herd tuberculin tested, with all tests conducted by USDA or Illinois Department of Agriculture veterinarians. Quarantine itself is a defined legal condition: it means members of the covered families are kept separate and apart from, and not allowed to come in contact in any way with, other cattle, bison, sheep, goats, antelope, or cervidae.

Suspicion does not require a positive live-animal test to justify quarantine. State law recognizes several triggers, including lesions grossly indicative of M. bovis found and confirmed at slaughter with a subsequent trace to the herd of origin, sale or transfer from an infected herd, possible physical or mechanical contact with animals from an infected herd, or epidemiologic analysis indicating possible spread. Once imposed, quarantine remains in effect until official tests or autopsies fail to disclose the presence of tuberculosis. Owners cannot simply opt out either: if an owner refuses to submit covered animals for a tuberculin test, the animals may be placed in quarantine until they are submitted for testing.

Depopulation is reserved for confirmed infection. The Department is directed by statute that when tests show cattle, bison, sheep, goats, antelope, or cervids are affected with tuberculosis, it is the Department’s duty to destroy them in the most expedient manner. The entire herd or flock may be depopulated once M. bovis infection is confirmed through tissue examination at the USDA laboratory in Ames, Iowa, or a comparable accredited lab, or with owner consent when slaughter lesions and epidemiological evidence support that step. Indemnity softens the financial blow but comes with conditions: indemnity is paid to owners of dairy and breeding cattle, bison, or cervidae that react and are destroyed only when the entire herd is tested, since reactors found without a complete herd test are not eligible. Feeder cattle and steers are excluded from indemnity except when an entire herd is depopulated due to tuberculosis infection. Appraisals for indemnity purposes are handled by a regularly employed state or federal veterinarian, who bases the value on the animal’s breeding value at the time of appraisal, factoring in age, breed, health status, weight, and market value at slaughter.

Penalties for Non-Compliance in Illinois

Illinois treats violations of the tuberculosis eradication statute as a specific class of offense with a defined fine range. Any person violating any provision of the Act is guilty of a business offense and shall be punished by a fine of not less than $50 nor more than $1,000. That penalty applies on top of, not instead of, the quarantine authority described above — refusing to present animals for testing does not avoid the requirement, it only adds a fine while the animals sit under quarantine until tested.

Common Mistake: Removing a reactor’s ear tag or branding is a separate violation from failing to test. Once the Department applies the “T” brand and special ear tag to a reactor, that identification must stay in place; tampering with it undermines the traceability the entire program depends on.

Because compliance touches movement paperwork as much as the test itself, incomplete certificates of veterinary inspection or missing herd-test history are the most common ways producers end up out of compliance without intending to break any rule. Pairing TB documentation with other routine Illinois animal health paperwork, such as the vaccination records covered in Illinois rabies vaccine requirements, helps producers build a habit of keeping every certificate current before an animal ever loads onto a trailer.

Illinois’s accredited-free status means most producers moving cattle within state lines will rarely think about tuberculosis testing at all. The requirements that do apply cluster around specific, predictable moments — bringing animals in from a non-accredited area, exhibiting cattle or cervids, or responding to a suspect test result — and knowing those trigger points ahead of time keeps a herd moving instead of sitting in quarantine while paperwork gets sorted out after the fact.