Brucellosis Laws in Mississippi: What Livestock Owners Need to Know

If you raise cattle, bison, swine, or other livestock in Mississippi, brucellosis regulations affect nearly every aspect of how you move, test, and manage your animals. Violating these rules — even unintentionally — can result in quarantine orders, forced slaughter, and criminal penalties under Mississippi law.

This guide walks you through the key brucellosis laws in Mississippi, from the state’s current disease-free classification to the specific testing windows, movement permit requirements, and consequences for non-compliance. Whether you are a commercial producer, a small hobby farmer, or a livestock transporter, understanding these rules protects your herd and keeps you on the right side of state and federal regulators.

What Is Brucellosis and Why It Is Regulated in Mississippi

Brucellosis is a contagious, infectious, and communicable disease primarily affecting cattle, bison, and swine, caused by bacteria of the genus Brucella. Brucella abortus primarily affects bovine species, though goats, sheep, and horses are also susceptible, while B. suis primarily affects porcine species.

In its principal animal hosts, brucellosis causes loss of young through spontaneous abortion or birth of weak offspring, reduced milk production, and infertility — and it can affect both animals and humans. The disease is transmitted from animals by direct contact with infected blood, placentas, fetuses, or uterine secretions, or through the consumption of infected material.

A longstanding national eradication program mostly eliminated the disease in U.S. cattle. Today, only occasional spillover cases occur in cattle and other livestock near the Greater Yellowstone Area (GYA), where wild bison and elk remain the last reservoir of the disease in the United States. Mississippi, far removed from that wildlife reservoir, maintains strong protections to ensure the disease does not re-enter the state through animal movement.

There is no economically feasible treatment for brucellosis in livestock. This is precisely why Mississippi, like all U.S. states, takes a prevention-first regulatory approach. The Mississippi Board of Animal Health (MBAH), operating under Miss. Code Ann. § 69-15-3, holds broad authority to set and enforce brucellosis rules for all livestock entering or moving within the state.

You can review broader context on pet vaccination laws in Mississippi for a comparison of how the state approaches disease prevention across different animal categories.

Mississippi’s Brucellosis Classification Status

The brucellosis regulations under 9 CFR Part 78 provide a system for classifying states or portions of states according to the rate of Brucella abortus infection present and the general effectiveness of a brucellosis control and eradication program. The classifications are Class Free, Class A, Class B, and Class C — and states or areas that do not meet the minimum standards for Class C status are required to be placed under Federal quarantine.

Mississippi is listed among the accredited-free states under federal tuberculosis regulations, which reflects the state’s broader standing as a disease-free jurisdiction for bovine diseases under USDA oversight. For bovine brucellosis specifically, Mississippi holds Class Free status under the USDA APHIS Brucellosis Eradication Program — the highest classification available.

Included among the requirements for Class Free status are that the cattle and/or bison herds in the state or area must have remained free from infections with field strains of Brucella abortus for at least 12 months. Restrictions on moving cattle and bison interstate become less stringent as a state or area approaches or achieves Class Free status.

The regulations of the APHIS Brucellosis Eradication Program vary based on the brucellosis status of each state. Because Mississippi is Class Free, livestock producers here benefit from fewer routine testing burdens compared to lower-classified states — but that status comes with obligations to maintain rigorous entry standards and surveillance. For comparison, see how brucellosis laws in Nebraska and brucellosis laws in Missouri handle their own Class Free obligations.

Vaccination Requirements for Cattle and Bison in Mississippi

There is a vaccine for brucellosis called RB51. Licensed for use in nonpregnant female cattle 4 to 12 months of age, the vaccine provides a significant level of protection — about 70 to 80 percent effective — and is also very effective at preventing abortions, which prevents further disease transmission.

RB51 is available only through an accredited veterinarian, state animal health official, or Federal area veterinarian in charge. You cannot simply purchase and administer this vaccine on your own — it requires professional administration and official documentation.

When an animal receives RB51 vaccination, it becomes an “official vaccinate” and is assigned a specific tattoo and ear tag. This identification matters significantly for movement purposes, as official vaccinates of beef breeds under 24 months of age and dairy breeds under 20 months of age may be eligible for reduced testing requirements when moving interstate.

Some states don’t allow cattle or domestic bison to be moved interstate for breeding without a record of brucellosis vaccination. Even though Mississippi itself is Class Free and does not mandate routine vaccination of all resident herds, your destination state may require vaccination documentation before accepting your animals.

All cattle or domestic bison owners, regardless of location, should discuss the advantages and disadvantages of vaccination with their veterinarian. This is especially important if you regularly sell breeding stock across state lines. You can also review brucellosis laws in Michigan and brucellosis laws in Minnesota to understand what receiving states may expect from your animals.

Testing Requirements for Cattle and Bison in Mississippi

Mississippi’s testing requirements are primarily triggered by an animal’s origin state classification and its age and reproductive status. Understanding which animals qualify as “test eligible” is the starting point for determining your obligations.

Test eligible cattle are defined as females not vaccinated over twelve (12) months of age, or males over eighteen (18) months of age. Animals that fall outside these categories — such as steers, spayed heifers, and official calfhood vaccinates within certain age thresholds — may be exempt from pre-movement testing requirements.

The following table summarizes testing requirements based on the origin state’s brucellosis classification:

Cattle from Free States may enter Mississippi provided they are individually identified on an official health certificate. There are no permanent test requirements and no permit is required.

Test eligible cattle from non-quarantined herds (excluding certified brucellosis-free herds) may enter Mississippi provided the cattle have been tested and are negative to the official brucellosis test within 30 days prior to entry, and are individually identified on an official health certificate.

A complete herd blood test must include all cattle or bison six months of age and older, except steers and spayed heifers, unless otherwise specified by a Designated Epidemiologist. When a full herd investigation is triggered — such as after a suspected case — this standard applies regardless of the animals’ vaccination history.

For other species, separate brucellosis testing rules apply. Dairy goats and dairy sheep over 6 months of age must be negative to an official tuberculin test and an official brucellosis test made within 30 days immediately preceding the date of entry. Exotic bovidae 6 months of age and over must also be tested negative for brucellosis within 30 days prior to entry.

Interstate and Intrastate Movement Rules in Mississippi

Movement rules in Mississippi operate on two levels: what USDA APHIS requires for interstate transport under 9 CFR Part 78, and what the Mississippi Board of Animal Health requires under Chapter 12 of its regulations. Both layers apply simultaneously, and you must satisfy both to move animals legally.

Owners and operators of private and common carriers, trucks, and other conveyances are forbidden to move any livestock or poultry into, or through this state except in compliance with provisions set forth in these regulations. This means the obligation extends beyond the animal owner — drivers and transporters are also legally accountable.

All livestock entering Mississippi must be in compliance with the United States Department of Agriculture’s Animal Disease Traceability Rule and must be accompanied by an official health certificate, except livestock consigned to slaughtering establishments under state or federal supervision accompanied by a USDA permit (VS Form 1-27), waybills, bills of lading, or certificate of ownership.

For cattle moving between Mississippi farms entirely within the state, the MBAH does not impose routine brucellosis testing requirements on resident herds that have not been quarantined or flagged through surveillance. However, if a herd is placed under quarantine following a positive or suspect test, all movement from that herd is restricted until the herd is cleared.

The following movement scenarios summarize key rules at a glance:

• Cattle from Class Free states entering Mississippi: Official health certificate with individual ID required; no test, no permit needed.
• Cattle from non-free states (certified free herd): Health certificate showing certified herd number required; entry permit needed; no pre-entry test if herd identity is maintained.
• Cattle from non-free, non-quarantined herds: Negative brucellosis test within 30 days, individual ID, health certificate, and entry permit all required.
• Steers, spayed heifers, and eligible official vaccinates: Steers and spayed heifers from any herd and official calfhood vaccinates of dairy breeds under 20 months of age, and official vaccinates of beef breeds under 24 months of age, which are not parturient or post parturient, from non-quarantined herds, can enter without test restrictions.
• Swine for breeding or show: All gilts, sows, and boars six (6) months of age and over for breeding or show purposes must be negative to an official brucellosis test made within 30 days immediately preceding the date of entry.
• International imports: All international imports require a prior entry permit. The permit requires the brucellosis and tuberculosis status of test eligible cattle, swine, and exotics.

For permit inquiries, you can call 601-359-1170 anytime day or night. You can also review how neighboring states handle similar movement rules by reading about brucellosis laws in Nevada for a western state perspective.

Reporting and Quarantine Requirements in Mississippi

Mississippi law places affirmative reporting obligations on licensed veterinarians and diagnostic laboratories. If you suspect brucellosis in your herd, the reporting chain begins with your veterinarian — not a voluntary decision, but a legal requirement.

The Mississippi Board of Animal Health has adopted canine brucellosis, along with a broad list of other diseases, as reportable to the State Veterinarian by licensed veterinarians and diagnostic laboratories. Bovine brucellosis falls under the same mandatory reporting framework, meaning any confirmed or suspected case must be reported promptly to the State Veterinarian.

Animal health professionals — including veterinarians, diagnostic laboratories, public health, zoo, or wildlife personnel, and others — report diagnosed or suspected cases of nationally listed reportable animal diseases to APHIS Area Veterinarians in Charge and to the state animal health official as applicable.

Once a report is filed, the quarantine process moves quickly. Once a herd is affected, animal health officials quarantine all infected and exposed cattle and bison and limit their movement to slaughter only. This continues until the disease is no longer present in the herd.

Animal health officials also investigate the detection to determine if other herds are affected and identify the most likely source of infection. They develop herd plans for affected herds, possibly exposed herds, and area herds to control, eradicate, and prevent the spread of the disease.

An approved individual herd plan is a herd management and testing plan designed by the herd owner, the owner’s veterinarian if requested, and a state or APHIS representative to determine the disease status of animals in the herd and to control and eradicate brucellosis within the herd. The plan must be jointly approved by the state animal health official and the Veterinarian in Charge.

If you operate a certified brucellosis-free herd, note that certified brucellosis-free herd status remains in effect for one year beginning with the date of issuance of the certificate. A negative herd blood test must be conducted within 10 to 12 months of the last certification date for continuous status.

Mississippi’s broader animal health regulatory environment extends to other livestock concerns as well. If you manage a farm operation, you may also want to review backyard chicken laws in Mississippi and beekeeping laws in Mississippi for related state-level agricultural regulations.

Penalties for Brucellosis Violations in Mississippi

Mississippi takes brucellosis violations seriously, and the penalty structure is designed to deter non-compliance at every level — from individual animal owners to commercial transporters.

Any person, firm, or corporation violating any of the provisions of Article 5 of Mississippi Code Chapter 15, or any of the rules and regulations of the Board of Animal Health relative to the control and eradication of cattle brucellosis or swine brucellosis, shall be subject to the provisions of Sections 69-15-53 through 69-15-69. Those sections establish the civil and criminal enforcement framework for livestock disease violations in the state.

When one or more animals are involved and are the subject of the violation, each animal shall constitute a separate violation. This per-animal penalty structure means that moving a group of untested cattle across state lines without proper documentation is not treated as a single offense — each animal in that group can generate an independent penalty.

Any carrier failing to comply with any of the provisions of the MBAH regulation, or interfering with any duly appointed representative of the Mississippi Board of Animal Health or USDA in the discharge of his duty, shall be deemed guilty of a misdemeanor and shall be punished as authorized in Sections 69-15-9, 69-15-111, and 69-15-331 of the Mississippi Code, Annotated.

Beyond criminal misdemeanor exposure, violations can trigger the following administrative and civil consequences:

• Mandatory quarantine: Infected or exposed herds are immediately quarantined, with movement restricted to slaughter only until the herd is cleared.
• Forced depopulation: In severe cases, the state or USDA may require the slaughter of infected and exposed animals. Indemnity payments may be available through cooperative state-federal programs, but are not guaranteed.
• Loss of certified herd status: A brucellosis finding immediately suspends any certified brucellosis-free herd certification, requiring the herd to restart the qualification process.
• Civil liability: Knowingly moving a brucellosis-positive animal that infects another producer’s herd may expose you to civil damages under Mississippi law.
• Federal penalties: Because interstate movement of livestock is governed by federal regulations under 9 CFR Part 78, violations involving interstate transport may also draw USDA APHIS enforcement action separate from state penalties.

Any person, firm, or corporation failing to comply with any of the provisions of the relevant section, or interfering with the State Veterinarian or any duly appointed officer of the State Veterinarian in the discharge of his duty, shall be deemed in violation and shall be subject to the penalties provided in Section 69-15-65, Mississippi Code of 1972.

If you are unsure whether your animals, your herd’s documentation, or a planned movement meets current MBAH requirements, contact the Mississippi Board of Animal Health directly at 601-359-1170 or consult an accredited veterinarian before transport. You can also explore how other states structure their enforcement by reviewing brucellosis laws in Minnesota or brucellosis laws in Michigan for comparison.

For other Mississippi-specific animal regulations that may affect your operation, see the state’s rules on kennel zoning, rooster ownership, and hedgehog ownership — all of which reflect how Mississippi balances agricultural tradition with public health and community standards.

Brucellosis compliance in Mississippi ultimately comes down to three habits: keeping accurate vaccination and testing records, verifying the disease status of any state you are importing animals from, and reporting suspected cases to your veterinarian without delay. Those three practices, consistently followed, protect your herd, your neighbors’ herds, and Mississippi’s valuable Class Free status.