Bovine Tuberculosis Testing Requirements in Louisiana: Rules Every Cattle Owner Must Know

Bovine tuberculosis testing requirements in Louisiana are shaped by both federal disease-classification rules and the state’s own administrative code, and getting the details wrong can stall a sale, a show entry, or a load of cattle at the state line. Louisiana carries a specific federal disease status that directly affects which animals need a tuberculin test before they move, sell, or exhibit. Whether you run a small cow-calf operation or manage a commercial dairy herd, understanding these rules protects your herd’s health record and keeps your cattle moving without costly delays.

This breakdown covers what triggers testing, which animals are covered, the approved test methods, and what happens if a suspect or positive result shows up on your farm.

Important Note: This article summarizes publicly available federal and Louisiana animal health regulations for general informational purposes. Always confirm current requirements with an accredited veterinarian or the Louisiana Department of Agriculture and Forestry (LDAF) State Veterinarian’s office before moving, selling, or exhibiting cattle.

What Is Bovine Tuberculosis and Why It Is Regulated in Louisiana

Bovine tuberculosis (TB) is a contagious, infectious, communicable disease of animals and humans caused by Mycobacterium bovis. It is commonly a chronic, debilitating disease but occasionally may assume an acute, rapidly progressive course, and disease is spread by direct contact, inhalation of droplets expelled from infected lungs, and ingestion of contaminated feed or milk. Because the organism crosses species lines, an infected herd is not just a cattle problem; it is a public health concern for anyone in close contact with the animals or their raw milk.

That risk is why Louisiana treats bovine TB as a high-risk disease with severe economic, animal health, and often public health consequences, and includes bovine tuberculosis among the state’s reportable animal diseases. A reportable animal disease must be reported to state and federal officials because USDA APHIS maintains a control or eradication program for it. On the federal side, APHIS and State animal health agencies collaborate with U.S. livestock producers to administer the National Tuberculosis Eradication Program, which has nearly eradicated tuberculosis from the Nation’s livestock population since its inception in 1917. Nationally, the disease is now rare — 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 — but that low number is the direct result of testing programs like the one Louisiana enforces.

For a broader look at how this disease compares to related conditions in livestock, see this overview of common bovine diseases and how they’re managed on Louisiana farms. Avian species carry a related but distinct condition, covered in this guide to avian tuberculosis.

Louisiana’s TB Classification Status and Risk Zones

Every state’s cattle population is assigned a federal disease-risk classification, and that classification determines how much testing is required for movement and sale. States, or zones within states, are classified in five categories: Accredited Free, Modified Accredited Advanced, Modified Accredited, Accreditation Preparatory and Non-Accredited, with the categories based on the number of confirmed TB cases found through surveillance.

Under the current federal regulation, Louisiana is listed among the modified accredited states, alongside most other states in the country, and Louisiana has no modified accredited zones, meaning the classification applies statewide rather than to a specific region. A modified accredited designation is defined as a State or zone that has the authority to enforce and complies with the Uniform Methods and Rules and in which tuberculosis has been prevalent in less than 0.1 percent of the total number of herds of cattle and bison in the State or zone for the most recent year.

Because Louisiana sits in the modified accredited tier rather than accredited-free, cattle originating here do not automatically qualify for the unrestricted interstate movement that cattle or bison that originate in an accredited-free State or zone may be moved interstate in accordance with 9 CFR part 86 without further restriction. That distinction matters most when you’re shipping cattle to a state with a higher TB status than your own.

Who Must Test and Which Animals Are Covered in Louisiana

The testing rules apply primarily to cattle and bison, though the broader federal framework also addresses captive cervids separately. All cattle and bison in a herd must be free from tuberculosis to establish or maintain accredited herd status, and to establish or maintain accredited herd status, the herd owner must comply with all of the provisions of the Uniform Methods and Rules regarding accredited herds.

Building that accredited status is not a one-time event. To qualify for accredited herd status, the herd must pass at least two consecutive annual tuberculin tests with no evidence of bovine tuberculosis disclosed, and all animals must be bonafide members of the herd. Once earned, the accreditation period will be 12 months (365 days) from the anniversary date and not 12 months from the date of the re-accreditation test.

Compliance is also a professional obligation for veterinarians. 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. If you’re adding new cattle to your herd, note that under Louisiana’s rules for herds outside a qualifying modified accredited area, individual animals for addition must pass a negative test within 60 days prior to entering the premises of the accredited herd and must be kept in isolation from all members of the accredited herd until negative to a test conducted after 60 days of date of entry.

Producers hauling cattle to meet these testing windows should also review livestock trailer requirements in Louisiana to make sure transport paperwork lines up with test dates.

Approved TB Testing Methods in Louisiana

Louisiana follows the same federally recognized testing sequence used nationwide. The first test to detect possible carriers of bovine tuberculosis is the Caudal Fold Tuberculin (CFT) test, in which a small amount of purified protein derivative (PPD) tuberculin is injected into the fold of skin at the base of the tail, and the CFT is read 72 +/- 6 hours later. If negative, no further action is required; if positive, the animal is classified as a responder and requires further testing.

Because the CFT is a screening tool rather than a final diagnosis, a false positive rate of 1-2% is expected during a whole herd test. Responders move to a confirmatory test:

• Comparative Cervical Test (CCT): A Comparative Cervical Tuberculin (CCT) test must be performed within 10 days, or after 60 days, of the CFT by a regulatory veterinarian, consisting of two injections given in the skin of the neck — one of bovine tuberculin extract and one of avian tuberculin extract.
• Gamma Interferon Assay: An alternative to the CCT is a whole-blood based test, the gamma interferon test, which must be performed within three (3) to 30 days following CFT injection.
• Slaughter Surveillance: Carcass inspection at federally and state-inspected slaughter plants remains a primary detection method for animals that were never live-tested.

Only qualified personnel can conduct and interpret these tests. Veterinarians are legally responsible for properly conducting and evaluating the results of tuberculin tests, and should perform the test themselves rather than delegate the responsibility to a technician. Every test must also be documented properly, since all cattle and bison tested shall be individually identified by official eartags and that identification recorded on the test form.

If you already manage other required health screenings for horses on the property, the testing cadence will feel familiar — see how it compares to EIA/Coggins test requirements in Louisiana.

Interstate and Intrastate Movement Testing Requirements in Louisiana

Movement testing depends heavily on where the cattle are going and their intended use. Within an accredited herd’s own testing cycle, tests must be conducted at 9-15 month intervals to maintain status. For cattle heading to Louisiana fairs, livestock shows, or breeders’ association sales, the state’s administrative code is direct on the tuberculosis condition: all cattle must originate from herds not under quarantine for tuberculosis, and all bulls must be accompanied by a current health certificate.

Herds already under quarantine face tighter movement controls. Sale of feeder calves from quarantined herds will be restricted, though feeder calves under 12 months of age that have passed a tuberculin test within 60 days of movement may be permitted to move intrastate under specific conditions. Movement destined for processing has its own carve-out: movement for immediate slaughter must be direct to a slaughtering establishment where approved state or federal inspection is maintained.

Pro Tip: Before hauling cattle across state lines, confirm the destination state’s TB classification. A modified accredited state like Louisiana often requires additional testing for animals entering a higher-status state, even when no testing would be required for in-state movement.

Ranchers coordinating pickups, hauling to sale barns, or transporting animals for testing appointments should double-check paperwork requirements outlined in the livestock trailer requirements guide, since a missing health certificate can hold up a shipment as effectively as a missed test.

What Happens When a Suspect or Positive Result Occurs in Louisiana

A “suspect” result on the initial screening test does not mean an animal is infected, but it does trigger a mandatory follow-up process. A suspect classification is entered when you observe or palpate any increase in caudal fold thickness, size, or sensitivity at the injection site, because a tuberculin injection results in a delayed hypersensitivity reaction manifested by swelling and induration when an animal has been exposed to the antigens present in bovine TB. A positive response usually begins within 8 to 12 hours and peaks about 72 hours after injection.

Once a suspect result is recorded, Louisiana’s own administrative code takes over: suspects to the tuberculin test shall be quarantined to the premises where found until retested by the comparative-cervical tuberculin test within 10 days of the caudal fold injection, or retested by the comparative-cervical tuberculin test after 60 days. If the test produces any type of response, the veterinarian must immediately notify the APHIS-VS Area Offices and State animal health officials.

If the confirmatory test comes back positive, the outcome is final for that animal. If reactor, the animal is humanely euthanized for necropsy and diagnostic testing of samples. A second inconclusive result doesn’t end the process either: if suspect, the animal is either sent for necropsy and sample testing, or remains in the herd under quarantine for a second CCT after 60 days have elapsed, and if the suspect animal is still positive on the second CCT, it will go for humane euthanasia to be necropsied and tested at a diagnostic laboratory. Confirmatory testing at the tissue level relies on laboratory work, where acidfast staining allows visualization of the bacteria in samples collected during necropsy.

Quarantine and Herd Depopulation Rules in Louisiana

Once a herd is confirmed affected, owners generally face two paths. When health officials find tuberculosis in a herd, it is managed by either depopulating the herd or by testing and removing reactor animals, since tuberculosis is not treated in livestock. In practice, the owner/producer, along with government agencies involved, can apply for whole herd depopulation OR develop a herd test and removal plan.

Herds that choose the test-and-removal route face an extended monitoring schedule. A herd in which Mycobacterium bovis infection has been disclosed shall remain under quarantine and must pass two tuberculin tests at intervals of at least 60 days and one additional test after six months. During that quarantine window, milk from the affected herd carries its own handling rule: all milk from affected herds must be pasteurized prior to human or animal consumption, which closes off the main path for zoonotic transmission to people on the farm.

Even after depopulation, the premises itself stays under scrutiny. If any livestock other than captive cervids are included in a newly assembled herd on a premises where a tuberculous herd has been depopulated, the State or zone must apply the herd test requirements contained in the Uniform Methods and Rules. That means bringing new cattle onto a formerly affected property doesn’t reset the clock on scrutiny — it starts a fresh testing obligation.

Penalties for Non-Compliance in Louisiana

Bovine TB’s status as a reportable disease in Louisiana means the obligations here aren’t optional courtesy steps. Reporting helps identify disease outbreaks, limits their spread, and minimizes the economic and health impacts on animals and people, and that’s the underlying reason state and federal officials retain quarantine and movement-restriction authority over noncompliant herds. Skipping a required herd test, moving quarantined cattle without authorization, or failing to report a suspect reaction exposes a producer to several consequences under existing rules:

1. Quarantine of the premises — animals found suspect or positive are confined until retesting requirements are met, regardless of the owner’s sale timeline.
2. Loss of accredited herd status — since accreditation depends on consecutive clean annual tests, a missed or failed test can reset the herd’s accreditation clock entirely.
3. Restricted or blocked sales — cattle from quarantined herds face limits on feeder calf sales and are barred from Louisiana fairs, livestock shows, and breeders’ association consignments until quarantine status changes.
4. Denied interstate movement — receiving states can refuse entry to cattle lacking the required health certificate or negative test results, leaving shipments stranded at the point of origin.