Brucellosis Laws in Maryland: What Livestock Owners Need to Know

Brucellosis is one of the most closely watched livestock diseases in the United States, and Maryland has a well-established regulatory framework designed to keep it that way. Whether you raise cattle, bison, or other susceptible livestock, understanding how Maryland’s brucellosis rules apply to your operation can protect your herd, your neighbors’ herds, and your standing with state and federal regulators.

This guide walks you through Maryland’s brucellosis classification status, vaccination and testing requirements, movement rules, reporting obligations, and the penalties that apply when violations occur. If you are buying, selling, or moving livestock across or within Maryland’s borders, this information is essential reading.

What Is Brucellosis and Why It Is Regulated in Maryland

Brucellosis is a contagious, infectious, and communicable disease primarily affecting cattle, bison, and swine, and is 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 and B. melitensis primarily affects goats and sheep.

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

Also known as contagious abortion or Bang’s disease, brucellosis is a costly disease of livestock and wildlife caused by bacteria in the genus Brucella, with significant consequences for animal health, public health, and international trade. That combination of economic and public health risk is precisely why Maryland — like all U.S. states — maintains active regulatory oversight of the disease. You can learn more about the biology and broader context of brucellosis at this detailed overview of brucellosis.

People can contract brucellosis by eating undercooked meat such as beef, sheep, goat, bison, elk, or wild hog, or by consuming unpasteurized milk or dairy products made from contaminated milk. This zoonotic risk is one of the primary reasons Maryland enforces strict livestock disease regulations — protecting both producers and the general public.

Maryland’s Brucellosis Classification Status

Maryland holds the highest possible designation under the federal brucellosis classification system. Under 9 CFR § 78.43, Maryland is listed among the validated brucellosis-free states, a designation that carries significant regulatory advantages for livestock producers moving animals in and out of the state.

A Class Free State or area is one that meets the standards for classification as brucellosis-free, meaning all cattle herds in the state must have remained free of Brucella abortus for 12 consecutive months based on surveillance and epidemiological investigations, with a cattle herd infection rate of 0.0 percent.

The brucellosis regulations contained in 9 CFR Part 78 provide a system for classifying states according to the rate of B. abortus infection present and the effectiveness of a brucellosis control and eradication program, with classifications of Class Free, Class A, Class B, and Class C. Restrictions on moving cattle and bison interstate become less stringent as a state approaches or achieves Class Free status.

Maryland is confirmed as a Brucellosis Class-Free State, meaning brucellosis testing is not required for Maryland-origin animals in many intrastate exhibition contexts. However, this free status does not eliminate all testing or reporting obligations — it simply reduces the burden compared to states with active infection.

All 50 states, Puerto Rico, and the U.S. Virgin Islands are brucellosis-free, except for occasional spillover cases occurring in livestock near the Greater Yellowstone Area due to bison and elk harboring the disease. Maryland, located far from that risk zone, faces no active wildlife reservoir threat, which helps it maintain its Class Free standing with minimal surveillance burden.

Vaccination Requirements in Maryland

Because Maryland is a Class Free state, mandatory calfhood vaccination programs are not universally required across all herds. However, vaccination remains an important tool — particularly for herds that move animals interstate or that border higher-risk areas — and federal standards still govern how vaccinations must be performed when they do occur.

The approved vaccine for brucellosis is RB51, licensed for use in nonpregnant female cattle 4 to 12 months of age. It 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. All cattle or domestic bison owners, regardless of location, should discuss the advantages and disadvantages of vaccination with their veterinarian.

• Vaccination must be performed by an accredited veterinarian or authorized state/federal official
• Only nonpregnant female cattle between 4 and 12 months of age are eligible for official calfhood vaccination
• Vaccinated animals must be permanently identified with a tattoo and an official vaccination eartag in the right ear
• Vaccination records must accompany any interstate health certificate when vaccination status is relevant to movement

An official calfhood vaccinate is defined as a female animal vaccinated while from 4 through 12 months of age by an APHIS representative, state representative, or accredited veterinarian with an approved brucella vaccine, and permanently identified by a tattoo and an official vaccination eartag in the right ear.

Some states don’t allow cattle or domestic bison to be moved interstate for breeding without a record of brucellosis vaccination. If you are shipping Maryland cattle to a destination state that requires vaccination documentation, you must ensure your animals meet that state’s specific requirements before movement — not just Maryland’s.

Maryland’s brucellosis vaccination regulations are codified under COMAR 15.11.02.10, which governs official vaccination of calves with approved Brucella vaccine. The state’s animal health regulations are administered under COMAR 15.11.01 through the Maryland Department of Agriculture.

Testing Requirements for Cattle and Bison in Maryland

Maryland’s testing requirements vary depending on the context — whether animals are being sold farm to farm, entering from out of state, or changing ownership through a dealer or auction. The state’s Class Free designation reduces routine testing burdens, but specific transactions still trigger testing obligations.

Intrastate Farm-to-Farm Sales

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 noted in specific dairy herd sale provisions.

For dairy herd sales specifically, brucellosis requirements apply, and all herds must comply with one of the following: have at least three negative milk ring tests within the 12 months immediately preceding the sale, or have a complete negative brucellosis herd test within the 12 months immediately preceding the sale.

Importing Cattle Into Maryland

Cattle for dairy and breeding purposes, feeder cows, heifers, bulls, and cattle for exhibition purposes may be imported into Maryland, provided they meet specific requirements. Cattle originating from herds not under restriction in certified brucellosis-free states require no brucellosis test.

For cattle originating from states that are not certified brucellosis-free, the rules are more detailed:

• Animals originating directly from certified brucellosis-free herds require no brucellosis test
• All other cattle (except steers) must originate directly from qualified herds and meet additional conditions
• Official vaccinates under 24 months old with vaccination dates recorded on the interstate certificate may qualify for entry
• Animals not meeting these criteria must have a negative brucellosis test conducted within the timeframe required by COMAR 15.11.01.04

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.

Official Testing Procedures

VS Form 4-33, Brucellosis Test Record, must be completed for each animal or herd tested, with a separate form required for each species tested. The form requires that a reason be provided for conducting the test — reasons may include interstate movement, sale, show or fair, diagnostic assessment such as abortion, or owner request.

For goats entering Maryland, the rules are stricter than for cattle. All goats entering the state for purposes other than immediate slaughter must be accompanied by an approved interstate health certificate showing a negative test for tuberculosis and brucellosis conducted within 30 days before the date of entry.

Interstate and Intrastate Movement Rules in Maryland

Movement rules in Maryland are shaped by both state COMAR regulations and federal 9 CFR Part 78 requirements. Because Maryland is a validated brucellosis-free state, animals originating here carry fewer movement restrictions than those from lower-classified states — but the rules for animals entering Maryland from other states are carefully structured.

Moving Cattle Into Maryland

The key factor when importing cattle for breeding or dairy purposes is the brucellosis classification of the origin state and herd. Maryland’s COMAR 15.11.01.04 establishes a tiered system:

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 and disinfected pens to prevent their exposure to infected cattle or premises.

Electronic Identification Requirements

The following types of cattle are required to have electronic ID (EID) when crossing state lines. This requirement, effective November 5, 2024, applies to animals undergoing official tests or vaccinations. Producers should be aware that removing existing official ID tags from any animal is illegal, and it is prohibited to place two 840 RFID tags with different numbers on a single animal, though management tags may be added as needed.

Moving Brucellosis-Exposed or Reactor Animals

Brucellosis-exposed cattle may be moved interstate directly to a recognized slaughtering establishment if the cattle are individually identified by an official eartag or a USDA backtag and accompanied by a permit or “S” brand permit. This pathway is tightly controlled to prevent disease spread through commercial channels.

For interstate movement of exposed animals to quarantined feedlots, brucellosis-exposed cattle may also be moved to a quarantined feedlot or from a farm of origin to a specifically approved stockyard approved to receive brucellosis-exposed cattle, provided they are individually identified and accompanied by the required permit.

If you are comparing Maryland’s movement framework with neighboring or similar states, you may find it useful to review brucellosis laws in Michigan or brucellosis laws in Nebraska for context on how Class Free states structure their movement rules differently.

Reporting and Quarantine Requirements in Maryland

Maryland requires timely reporting of suspected or confirmed brucellosis cases as part of its obligations under both state law and the federal cooperative eradication program. Brucellosis is a listed reportable disease in Maryland, and failure to report can result in regulatory action.

Animal health professionals — including veterinarians, diagnostic laboratory personnel, public health officials, zoo and wildlife personnel, and others — must 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 under state reporting regulations.

If infection is suspected or confirmed, regulatory officials will contact you, the owner, or both, to develop a herd plan. This herd plan is a formal document that outlines the steps required to control and eradicate the disease within the affected operation.

Quarantine Procedures

Disease control and eradication measures include quarantines to stop the movement of possibly infected or exposed animals, testing and examination to detect infection, destruction of infected or sometimes exposed animals to prevent further disease spread, and cleaning and disinfection of contaminated premises.

Under Maryland’s COMAR 15.11.02.05, handling of brucellosis reactor and exposed cattle follows specific protocols that align with federal Uniform Methods and Rules. Key quarantine provisions include:

• Reactor animals must be identified with official ear tags and moved only to approved slaughter facilities
• Exposed animals may be placed under quarantine on the premises of origin pending further testing
• Quarantined premises are subject to inspection by Maryland Department of Agriculture officials
• All test-eligible animals in a quarantined herd must be subjected to official testing before the quarantine can be lifted

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.

Regulations provide that if a herd is found to be affected with brucellosis, the herd may be required to be depopulated within 60 days of an infected animal being detected, and if two or more herds are found to be affected with brucellosis within a two-year period or if an affected herd is not depopulated within 60 days, the state or area can lose its Class Free status. This underscores the urgency of prompt reporting and compliance.

Maryland’s animal health reporting structure is administered through the Maryland Department of Agriculture’s Animal Health Section. You can reach them at 50 Harry S. Truman Parkway, Annapolis, MD 21401. For context on how Maryland’s broader animal import rules intersect with disease reporting, see the state’s pet and animal import laws.

Penalties for Brucellosis Violations in Maryland

Maryland takes brucellosis violations seriously, and the consequences for non-compliance can be both financial and operational. Penalties are authorized under the Agriculture Article of the Annotated Code of Maryland, which grants the Maryland Department of Agriculture broad enforcement authority over animal disease control.

Regulatory Authority

Maryland’s brucellosis regulations are codified under COMAR 15.11.02 and authorized by Agriculture Article, § 3-101 of the Annotated Code of Maryland. The Maryland Department of Agriculture has authority to issue quarantine orders, require testing and depopulation, and pursue civil and criminal penalties for violations.

Types of Violations and Consequences

Violations of Maryland’s brucellosis laws generally fall into several categories, each carrying distinct consequences:

Producers should be aware that removing existing official ID tags from any animal is illegal. This applies to both the state and federal levels — tampering with official identification used in brucellosis vaccination or testing programs can trigger enforcement under both COMAR and federal regulations.

Loss of Herd Certification

One of the most significant non-monetary penalties a Maryland producer can face is the loss of certified brucellosis-free herd status. Certified brucellosis-free herd status remains in effect for one year beginning with the date of issuance of the certified brucellosis-free herd certificate. Failure to maintain required surveillance testing within the prescribed window results in lapsed certification, which can restrict the owner’s ability to sell or move animals.

To maintain herd certification, a negative herd blood test must be conducted within 10 to 12 months of the last certification date for continuous status. Lapsed certification may be reinstated if a herd blood test is conducted within 14 months of the last certification date.

Federal Enforcement Overlap

The regulations of the APHIS Brucellosis Eradication Program vary based on the brucellosis status of each state. Minimum standards are set forth in the Brucellosis Eradication Uniform Methods and Rules; however, some states have more restrictive requirements. In Maryland, state and federal enforcement can overlap — a violation of COMAR 15.11.02 may simultaneously constitute a violation of 9 CFR Part 78, exposing producers to both state and federal penalties.

If you operate livestock in multiple states, reviewing how penalties and compliance requirements compare across state lines is worthwhile. See how other states handle these issues: brucellosis laws in Minnesota, brucellosis laws in Missouri, and brucellosis laws in Nevada.

Maryland livestock owners who have questions about compliance, testing schedules, or enforcement procedures should contact the Maryland Department of Agriculture’s Animal Health Section directly or consult with an accredited veterinarian familiar with APHIS brucellosis program requirements. Staying current with both COMAR and federal rules is the most reliable way to protect your herd, your certification status, and your operation from costly enforcement actions.

For more on Maryland-specific animal laws that may affect your livestock operation, explore related topics including goat ownership laws in Maryland, backyard chicken laws in Maryland, and rooster laws in Maryland.