Brucellosis Laws in New Mexico: What Livestock Owners Need to Know

Brucellosis is one of the most closely regulated livestock diseases in the United States, and New Mexico takes its prevention seriously. Whether you raise cattle, bison, dairy goats, or swine, understanding the state’s brucellosis rules is essential to staying compliant and protecting your herd.

This guide walks you through New Mexico’s brucellosis classification status, vaccination and testing requirements, movement rules, reporting obligations, and the penalties you can face for violations — all drawn from the New Mexico Livestock Board (NMLB) and state administrative code.

What Is Brucellosis and Why It Is Regulated in New Mexico

Brucellosis, also known as contagious abortion or Bang’s disease, is a costly disease of livestock and wildlife caused by a group of bacteria in the genus Brucella. The disease has significant consequences for animal health, public health, and international trade, occurring mainly in cattle, bison, and swine, but it can also affect cervids, goats, sheep, horses, and people.

In cattle and bison, the bacteria of concern is Brucella abortus, which has been present in the United States since the 1930s. In livestock, the disease most commonly causes reproductive losses — including abortions, stillbirths, and reduced milk production — that can devastate a herd’s productivity and market value. In humans, it is a zoonotic disease transmitted primarily through contact with infected animals or consumption of unpasteurized dairy products.

A longstanding national eradication program mostly eliminated the disease in U.S. cattle, and today only occasional spillover cases occur in cattle and other livestock near the Greater Yellowstone Area (GYA). New Mexico’s proximity to livestock trade routes, its active ranching industry, and its border with Mexico all make ongoing brucellosis regulation a practical necessity for the state.

Current USDA APHIS Veterinary Services disease eradication programs include cooperative State-Federal efforts directed at cattle and swine brucellosis, bovine and cervid tuberculosis, and pseudorabies in swine. New Mexico participates in this cooperative framework, with the New Mexico Livestock Board serving as the primary state enforcement agency. You can learn more about brucellosis as a disease before reviewing the specific state rules below.

New Mexico’s Brucellosis Classification Status

New Mexico holds Class Free status for brucellosis — the highest classification available under the USDA’s cooperative eradication framework. This designation has significant practical implications for how livestock can move into and out of the state.

Included among the requirements for Class Free status are that the cattle and/or bison herds in the state or area within the state must have remained free from infections with field strains of Brucella abortus for at least 12 months. Maintaining this status requires ongoing surveillance and strict compliance with import rules to prevent reintroduction of the disease.

To prevent introduction of brucellosis into New Mexico and to comply with USDA regulations, animals from non-free status states must meet specific requirements. As noted by the NMLB, the only Class A non-free state is Montana. All other states from which you are importing livestock are considered Class Free, which simplifies the entry process considerably.

For context on the broader classification system: two of the requirements for Class A status are that the infection rate for cattle and bison herds may not exceed 0.1 percent during the previous 12 months and that the successful case closure (SCC) percentage for the previous 12-month period meets the program threshold. Two of the requirements for Class B status are that the infection rate for cattle and bison herds may not exceed 1.00 percent during the previous 12 months and that the SCC percentage must be at least 90 percent during the previous 12 months.

New Mexico’s Class Free standing means that cattle moving out of the state face fewer testing barriers in most receiving states, and that cattle moving into New Mexico from other Class Free states are not subject to brucellosis entry testing. If you are also managing livestock in neighboring states, reviewing brucellosis laws in Nevada or brucellosis laws in Nebraska can help you understand how classification differences affect cross-border movement.

Vaccination Requirements in New Mexico

New Mexico does not mandate a universal statewide calfhood vaccination program for all herds, but official vaccination status plays a central role in determining testing requirements — especially for animals being imported from non-free states. Understanding when vaccination exempts an animal from testing is important for both importers and resident producers.

Beef cattle imported from non-free states must meet the following requirements: all breeding age animals 18 months of age and older require a negative test. If proof of prior calfhood vaccination exists, a negative brucellosis test is required only if the animal is over 24 months of age. This means officially vaccinated beef heifers under 24 months of age from a Class A state are exempt from the pre-entry test requirement.

Dairy cattle imported from non-free states require a negative test of all breeding animals if over 18 months of age. For dairy heifers that have been officially vaccinated, the age threshold for the exemption is lower — vaccinated dairy heifers under 20 months of age from Class A states are exempt from the negative test requirement prior to entry.

Dairy goats imported from non-free states must have a negative brucellosis test, unless originating from a certified brucellosis-free herd. This rule reflects the fact that Brucella melitensis, which affects goats and sheep, is a separate concern from bovine brucellosis. If you manage goats in New Mexico, also review the state’s goat ownership laws for broader regulatory context.

When vaccination is performed as part of a whole-herd plan, there are additional considerations for certified herd status. The Certified Brucellosis-Free Herd status is valid for 12 months unless evidence of brucellosis is disclosed or the herd participates in a whole-herd vaccination plan, in which case the herd status is suspended until postvaccination testing is completed.

Testing Requirements for Cattle and Bison in New Mexico

Testing requirements in New Mexico vary depending on whether animals are being imported, sold at a livestock market, or identified as exposed or infected within the state. The NMLB administers these requirements under Title 21 of the New Mexico Administrative Code (NMAC).

Intrastate Sale Barn Surveillance

Breeding age animals sold within the state of New Mexico are tested at sale barns as part of a surveillance program. This ongoing market-level testing helps the state maintain its Class Free status by catching any potential infections before they spread through commercial livestock channels.

Testing of Imported Cattle

The testing requirements for imported cattle depend on the brucellosis classification of the state of origin:

• Class Free states: All cattle must meet federal interstate regulation requirements for “class free” states, in addition to New Mexico requirements. No brucellosis entry test is required for cattle from certified free herds.
• Class A states: All females and bulls over 18 months of age must be tested and negative within 30 days prior to entry into New Mexico, except heifers that are officially vaccinated for brucellosis and under 24 months of age if beef, and under 20 months of age if dairy.
• Class B states: All females and breeding bulls over 8 months of age must be tested and negative within 30 days prior to entry into New Mexico, except heifers that are officially vaccinated for brucellosis and under 24 months of age if beef, and under 20 months of age if dairy.
• Class C states: No sexually intact cattle, regardless of age, will be allowed to be moved into New Mexico, except “S” branded animals going to slaughter or quarantined feedlots. The restrictions will not affect spayed heifers or steers.

There is no brucellosis test required for spayed heifers and steers regardless of the state of origin’s classification. All tests shall be at the owner’s expense.

Testing of Infected or Exposed Animals

All cattle known to be infected with brucellosis, or cattle that have been exposed to infected cattle, shall be tested for brucellosis within 45 days of a written notice directed to the owner of the cattle by the board. This mandatory post-exposure testing window gives the NMLB a mechanism to quickly identify and contain any potential spread within the state.

All cattle testing positive to the brucellosis test shall go directly to slaughter and be slaughtered in accordance with federal government standards as stated in Part 51, Title 9 of the Code of Federal Regulations.

Swine Testing

All swine, regardless of age, must prove negative to a brucellosis test conducted within 30 days, or originate from a brucellosis “validated herd” and have the date of the last herd test and the herd certificate number indicated on the approved certificate of veterinary inspection. This applies to all swine entering New Mexico regardless of the originating state’s classification status.

Interstate and Intrastate Movement Rules in New Mexico

Movement of cattle and bison in New Mexico — whether crossing state lines or moving within the state — is subject to a layered set of requirements that involve both federal and state oversight. Failing to comply with these rules can result in your shipment being turned back or quarantined.

Arrival Inspection Requirements

Upon arrival at destination, the owner or agent must notify the New Mexico Livestock Board inspector in order to make arrangements for inspection of the shipments prior to commingling with other cattle or release to pasture. You cannot simply unload and turn animals out — inspection must happen first.

The inspection will be for the purpose of determining that the shipment has met all applicable import requirements including but not necessarily limited to: scabies dipping, brucellosis testing, tuberculosis testing, brand regulations, and inspection to confirm the shipment conforms to the description of the animals as stated on the required permit and health certificate.

Slaughter and Feedlot Exemptions

Testing or vaccination requirements for Class A and Class B states are not required when going directly from the farm or ranch of origin to a federally approved slaughter plant for slaughter, or to a New Mexico quarantined feedlot, or when going to an approved market where the qualification for brucellosis will be handled at the market. This exemption exists because animals moving directly to slaughter pose no ongoing breeding or herd transmission risk.

For Class B state animals that do go through the standard entry process, there is an additional follow-up requirement: test-eligible animals over 8 months of age will be quarantined at destination for a retest for brucellosis at the owner’s expense, unless waived by the board, between 60 and 90 days after the entry test date.

Certified Brucellosis-Free Herd Exemption

For all states, regardless of brucellosis class, cattle originating from any “brucellosis certified free” herd may enter New Mexico without an entry test, provided the following information is recorded on the official health certificate. This is one of the most practical pathways for importers looking to avoid pre-entry testing delays, and it applies even to animals from Class A or Class B states.

If you are navigating livestock movement rules across multiple states, it is worth comparing how neighboring states approach the same issues. See brucellosis laws in Missouri and brucellosis laws in Minnesota for additional reference points.

Reporting and Quarantine Requirements in New Mexico

New Mexico’s brucellosis regulations impose strict reporting and quarantine obligations on livestock owners, veterinarians, and others who discover or suspect brucellosis infection. These requirements are designed to contain outbreaks quickly and prevent spread to neighboring herds.

Mandatory Reporting

Brucellosis is listed as a reportable disease in New Mexico under 21.30.4.9 NMAC, appearing on both the list of diseases of significance to public health and zoonoses and the list of diseases of concern to livestock. The asterisk notation next to brucellosis on the state list indicates it must also be reported to the New Mexico Department of Health when it occurs in livestock.

When brucellosis is discovered or diagnosed, it must be immediately reported to the New Mexico Livestock Board’s state veterinarian. This obligation applies to accredited veterinarians, livestock owners, and anyone else who discovers or has reason to believe brucellosis is present in an animal.

Herd Quarantine Procedures

If a market cattle infection (MCI) reactor is directly from a New Mexico origin herd, the New Mexico Livestock Board or its authorized representative shall quarantine the herd of origin, and no animals shall be moved from the herd without a special permit of the board or its authorized agent, until the herd is declared negative and the quarantine lifted.

No one shall be allowed to remove any animal, animals, or carcasses thereof from the custody of any livestock inspector, or any person designated by the board, who has taken up, seized, or impounded the said animal, animals, or carcasses for the purpose of determining ownership, preventing theft, trespass, or the spread of disease.

Quarantine boundaries are established formally by the board. Physical boundaries are established by order of the board or a duly authorized agent of the board for the purpose of controlling the movement of livestock to prevent the spread of disease. Sealed vehicles and locked gates with numbered metal strips are used to enforce these boundaries and ensure the integrity of the quarantine zone.

Disposition of Positive-Testing Animals

Once an animal tests positive, the path forward is clear and non-negotiable: all cattle testing positive to the brucellosis test shall go directly to slaughter and be slaughtered in accordance with federal government standards as stated in Part 51, Title 9 of the Code of Federal Regulations. There is no treatment pathway or holding option for confirmed positive animals under New Mexico law.

For broader context on how New Mexico regulates other aspects of livestock and animal ownership, you may also find it helpful to review the state’s backyard chicken laws and beekeeping laws, which reflect the same regulatory framework administered by state agriculture authorities.

Penalties for Brucellosis Violations in New Mexico

Violating New Mexico’s brucellosis regulations can result in criminal and civil consequences. The state’s penalty structure is grounded in the New Mexico Livestock Code and the administrative rules issued by the NMLB.

Criminal Penalties

Violations are subject to criminal and civil penalties pursuant to Sections 77-2-9 and 77-2-22 NMSA 1978. Penalties for misdemeanor crimes can include imprisonment of less than one year or fines up to $1,000 or both. Penalties for petty misdemeanors can include imprisonment not to exceed six months or fines up to $500 or both.

Furthermore, any person who violates a rule adopted under the power granted to the board, unless the penalty has been fixed by law, is guilty of a misdemeanor and upon conviction shall be sentenced in accordance with the provisions of Section 31-19-1 NMSA 1978.

Importing dairy cattle in violation of New Mexico’s disease control rules carries its own specific penalty. A person who brings into New Mexico any dairy cattle in violation of the provisions of Chapter 77, Article 5 NMSA 1978 or of any of the rules promulgated by the board for the enforcement of that article is guilty of a misdemeanor and upon conviction shall be sentenced in accordance with the provisions of Section 31-19-1 NMSA 1978.

Quarantine Violations

Moving animals in violation of a quarantine order is among the most serious brucellosis-related offenses you can commit in New Mexico. Livestock cannot be removed from a VS-quarantined premise. Any livestock introduced onto VS-quarantined premises will be subject to the quarantine restrictions and remain on the premises until the quarantine is lifted. Attempting to circumvent a quarantine — whether by removing animals without a permit or introducing new animals onto a quarantined property — exposes you to both criminal prosecution and the loss of those animals.

Marking Requirements for Positive Animals

Whenever cattle or bison within this state are tested for tuberculosis or Bang’s disease by the board or its agents, or by an authorized agent or employee of the USDA APHIS, if an animal so tested is found to have a positive reaction to such tests, it shall be permanently marked or branded according to the requirements of the board by the owner or his agent. Failure to comply with this marking requirement is itself a separate violation of state law.

If you operate livestock across multiple states, understanding how penalties and enforcement compare elsewhere can help you build a compliance strategy. See how brucellosis laws in Michigan handle violations as a point of reference. You may also want to review New Mexico’s roadkill laws and leash laws if you are managing a broader range of animal-related compliance questions in the state.

Staying current with the New Mexico Livestock Board’s published rules — particularly under Title 21 NMAC — is the most reliable way to ensure you are meeting all brucellosis requirements. When in doubt, contact the NMLB directly or consult an accredited veterinarian before moving animals across state lines or selling breeding-age animals at market.