If you own, transport, or compete with horses in Montana, the Coggins test is one of the most important compliance documents you will need to understand. Equine Infectious Anemia (EIA) is a transmissible infectious disease of horses caused by an RNA virus, and infected horses remain infected for life — there is no preventive vaccine and no curative treatment. EIA is a reportable disease regulated by the United States Department of Agriculture (USDA) and state animal health regulatory agencies.
Montana takes EIA seriously, and the state’s rules touch nearly every major equine activity — from crossing county lines to entering a show pen or changing ownership. Whether you are a lifelong rancher or new to keeping horses in the Treasure State, knowing exactly when testing is required, which animals are covered, and what happens after a positive result can protect your animals and keep you on the right side of state law.
Pro Tip: Keep a digital and paper copy of your horse’s current Coggins certificate in your truck cab at all times when hauling. Montana operates highway checkpoints where brand inspections and health papers are verified, and documents buried in the trailer tack room may not be accessible when you need them.
What Is Equine Infectious Anemia (EIA) and Why It Is Regulated in Montana
Equine Infectious Anemia is a transmissible infectious disease of horses caused by an RNA virus in the Lentivirus genus, family Retroviridae. The virus is commonly referred to as EIAV, and in nature it is a vector-transmitted disease in which blood-feeding insects transfer virus-infective blood between horses. Horse flies, deer flies, and stable flies are the most common vectors.
Transmission of EIAV is directly related to blood retained on or in the mouthparts of an insect after feeding on an infected host. The virus does not replicate in the insect vector and must be physically transferred to a susceptible host. Beyond insects, equine infectious anemia virus can also be transmitted unintentionally by mechanical means, or “iatrogenically,” by transfusion of infective blood or blood-contaminated instruments.
The disease progresses through three phases: acute, recurrent, and chronic, where horses may not exhibit any signs of infection but can still be carriers and transmitters of the virus. Contracting EIA can also be fatal, and horses with chronic EIA may experience flare-ups during periods of stress or use of corticosteroids. Montana regulates the disease because EIAV infection poses a major risk to the equine industry in any form, and surveillance through routine diagnostic testing is the mainstay of prevention.
Montana has confirmed EIA cases in recent years. “Cases of EIA in Montana are sporadic and unfortunately, we are not always able to identify the original source of infection,” said Tahnee Szymanski, Montana State Veterinarian. The Montana State University Extension notes that the Montana Department of Livestock recommends regular EIA testing as part of a good equine health management program.
Which Animals Require a Coggins Test in Montana
EIA is a viral disease impacting horses, mules, and donkeys. Montana’s regulations extend to all equidae, meaning the Coggins test requirement applies broadly across the equine family. EIA is a potentially fatal viral disease of equids — horses, ponies, zebras, mules, and donkeys — transmitted on the mouthparts of certain biting and blood-sucking insects.
Under Montana Administrative Rule 32.3.216, all horses, mules, asses, and other equidae that are moved into the state of Montana must be accompanied by an official certificate of veterinary inspection from the state of origin stating that the equidae are free from evidence of any communicable disease and have completed EIA test and identification requirements.
There are two notable exemptions to be aware of:
- A nursing foal under six months of age accompanied by an EIA-negative dam is exempt from the test requirements.
- Working equids used for seasonal ranching purposes may be exempt from the requirements of this rule if the animals have been included on a current seasonal grazing permit that has received prior approval from the Department of Livestock and the chief livestock sanitary official of the neighboring state.
If you own horses in Montana and are unsure whether your animals fall under a specific exemption, contact the Montana Department of Livestock Animal Health Bureau directly at 406-444-2976 or email livpermits@mt.gov.
When a Coggins Test Is Required in Montana
Montana requires a negative Coggins test in several common equine situations. A Coggins test is required when a horse is imported into Montana or exported out of Montana to another state. Beyond movement, because EIA is easily transmitted and there is no cure, it is important that horse owners, clinicians, and barn managers are diligent about testing horses on an annual basis, as well as requiring proof of negative tests for any equine event and change of ownership.
Within the United States, a negative AGID or ELISA test within the previous 12 months is required by all states on any horse being moved interstate, changing ownership, entered into exhibitions or competition, or being sold at auction or sales markets. Montana follows this federal framework and enforces it through state administrative rules.
In Montana, a negative Coggins test is valid for 12 months. However, if you use a Six-Month Equine Passport for travel among the western cooperative states, the EIA test is valid for only 6 months under that certificate type. The table below summarizes the key triggering events:
| Triggering Event | Coggins Required? | Test Validity |
|---|---|---|
| Importing equids into Montana | Yes | 12 months prior to entry |
| Exporting equids out of Montana | Yes | 12 months |
| Interstate movement (all states) | Yes | 12 months (6 months under Six-Month Passport) |
| Change of ownership / sale | Yes | 12 months |
| Auctions and sales markets | Yes | 12 months |
| Exhibitions, shows, and competitions | Yes | 12 months (some events require 6 months) |
| Nursing foal under 6 months with negative dam | Exempt | N/A |
You should also be aware that most facilities require proof of a negative Coggins within 12 months, although some high-level competitions may want it within 6 months. Always check with the specific event organizer before travel.
How the Coggins Test Works and Approved Testing Methods in Montana
A Coggins test is a blood test that looks for antibodies against the transmissible viral disease Equine Infectious Anemia. The test was developed over 45 years ago and is named after its developer, Dr. Leroy Coggins. Definitive diagnosis of EIA is made by identifying antibodies in a blood sample.
Two types of diagnostic tests are approved by the USDA for diagnosis of EIAV: the agar gel immunodiffusion (AGID) test and several enzyme-linked immunosorbent assay (ELISA) tests. The ELISA tests are popular for their simplicity and rapid results. The ELISA tests are more sensitive than the AGID but may occasionally yield false-positive results. The AGID test, commonly known as the Coggins test, is the most widely used tool for diagnosing equine infectious anemia.
All ELISA-positive tests must be confirmed with an AGID test. When used together, the Coggins and ELISA tests provide the highest level of accuracy. In cases where results conflict, the Western blot test is a specialized diagnostic tool that may be used to clarify conflicting results.
Diagnostic samples for EIAV testing may only be submitted by a state or federal animal health official or accredited veterinarian. This means you cannot self-collect and submit a sample — you must work with a licensed vet. Once the laboratory processes results, horse owners can instantly access their digital Coggins certificate through MyVetLink, GlobalVetLink’s secure 24/7 online portal.
Pro Tip: Schedule your horse’s annual Coggins blood draw at the same time as routine vaccinations. MSU Extension recommends adding the test to your annual vaccination regimen so your horse is always covered for any event or sale.
For more information on responsible equine health management in Montana, see our guide on brand inspection requirements in Montana, which often accompanies Coggins documentation for travel.
Interstate Movement and Import Requirements in Montana
Moving horses across Montana’s borders involves more than just a valid Coggins test. A health certificate must be issued within 30 days of entry under ARM 32.3.202 and ARM 32.3.206, except that horses from Arizona must have a CVI issued within 7 days of entry into Montana.
An import permit is only required for handwritten CVIs issued on paper and is not required for electronic health certificates under ARM 32.3.207. You can call 406-444-2976 to obtain an import permit. Official identification — a description of the horse including age, color, sex, and breed, or an equine microchip number — must be listed on the health certificate under ARM 32.3.1401.
Entry of equidae into Montana shall not be allowed until the EIA test has been completed and reported negative. Equidae with tests pending are not acceptable. This is a firm rule: you cannot bring a horse into Montana on the basis of a pending result.
Montana also participates in the Extended Equine Certificate of Veterinary Inspection (EECVI) program for frequent travelers. An EECVI is valid for six months from the CVI inspection date or until the horse’s current EIA/Coggins test expires, whichever comes first. Since EIA tests are typically valid for 12 months from the blood draw date, the EECVI expiration is determined by whichever date occurs sooner.
For travel among the western cooperative states specifically, with a Six-Month Passport for travel between Montana, Idaho, Washington, Oregon, Nevada, and California, the EIA test is valid for 6 months. This certificate is valid for travel into Montana, Idaho, Nevada, California, Oregon, and Washington only — no other states recognize this certificate.
Montana is somewhat unique in that horses need state identification to travel within and outside of the state. There are nine states that do this in the West. Brand identification and travel requirements are mandated by Montana’s Department of Livestock, based in Helena. You can find a local brand inspector for your county at liv.mt.gov.
If you plan to return to Montana after traveling out of state, note that a Montana re-entry permit is required and must be obtained by the veterinarian issuing the certificate. Always verify the destination state’s requirements before loading up, since each state has its own set of laws pertaining to import requirements, and when traveling you are not only governed by Montana re-entry requirements and state of destination requirements, but may also fall under laws in other states if you off-load your horse for any reason in that state.
For related Montana animal regulation topics, see our article on exotic pets that are legal in Montana and our overview of venomous animals in Montana that may affect horses in pasture settings.
What Happens When a Horse Tests Positive in Montana
A positive EIA test result triggers an immediate and structured response from the Montana Department of Livestock (MDOL). The infected horse in a recent Musselshell County case was discovered when it tested positive on a screening test required for equids to move across state lines. The preliminary positive result was confirmed by the USDA-APHIS National Veterinary Service Laboratories (NVSL) in Ames, Iowa. NVSL confirmation is the standard procedure for any suspect positive in Montana.
A veterinarian is required to report positive test results to the state. Once MDOL receives a confirmed positive notification, the department will investigate the movement and ownership history for the infected animal to identify other horses that may have been exposed to the disease. Exposed animals will be tested to verify disease status.
When the Montana Department of Livestock receives notification that a horse has tested positive for EIA, the property where the animal is housed is placed under quarantine and follow-up testing on the animal is underway. The state veterinarian’s office coordinates all subsequent steps.
Important Note: EIA-positive status is permanent. There is no treatment that clears the infection, and no vaccine exists to prevent it. A confirmed positive horse will face lifetime management restrictions regardless of whether it shows outward symptoms.
If you suspect your horse may have been exposed to an EIA-positive animal, contact the Montana Department of Livestock immediately at 406-444-2976. Early notification allows the department to conduct epidemiological tracing and limit the spread to other horses on neighboring properties.
Quarantine, Euthanasia, and Isolation Rules in Montana
Once a horse is confirmed EIA-positive in Montana, the owner faces three possible outcomes under state and federal regulations. Due to strict regulations and no available treatment, there are limited options for the management of infected horses. Infected horses can be placed under a lifetime quarantine with a minimum of 200 yards distance between the quarantined animal and other equines, euthanized, or donated for EIA-related research.
The 200-yard separation requirement is a federal standard enforced at the state level. A confirmed EIA-positive equid must be euthanized or quarantined for life 200 yards away from any EIA-negative equid as per USDA EIA program rules. This distance is designed to prevent mechanical transmission by biting insects, which typically cannot carry viable virus over that distance.
Horses that are infected with EIAV are infected for life. As a result, infected horses must be euthanized or separated for life from all other equids. The choice between euthanasia, lifetime quarantine, or research donation belongs to the owner, but all three options carry significant practical and financial implications.
Horses placed under lifetime quarantine cannot be moved from the property without special written permission from the Montana State Veterinarian. Equidae that test positive to the EIA test shall not be permitted entry into Montana except by special written permission from the state veterinarian and must be branded and moved in conformity with the U.S. Department of Agriculture EIA movement regulations.
For context on how Montana handles other animal health and identification requirements, our article on brand inspection requirements in Montana covers the branding and identification rules that also apply to quarantined equids.
Penalties for Non-Compliance in Montana
Failing to comply with Montana’s EIA testing and documentation requirements carries real consequences. The Montana Department of Livestock enforces animal health rules under Montana Code Annotated (MCA) Title 81, and violations can result in both civil and criminal penalties.
Violations of Montana’s livestock laws can result in significant penalties, deterring non-compliance and ensuring adherence to the legal framework. Penalties range from financial to criminal charges, depending on the infraction’s severity. Specifically, transporting livestock without a permit can result in fines up to $500 per violation, and non-compliance with health and safety regulations can incur fines from $100 to $1,000. Repeat offenders may face increased fines.
Beyond financial penalties, horses transported without proper Coggins documentation can be held at a highway checkpoint until paperwork is produced. Several western states — notably California, Idaho, Montana, and Wyoming — operate highway checkpoints or ports of entry where brand inspections and health papers are verified. If you are stopped without proper documentation, your horses can be held at the checkpoint until paperwork is produced.
Knowingly moving an EIA-positive horse without state veterinarian authorization is a more serious violation and can trigger criminal charges under Montana livestock law. The state veterinarian’s office has the authority to order immediate quarantine of any premises where an illegally transported EIA-positive animal is found.
To stay compliant, follow these core steps:
- Test all horses annually with an accredited veterinarian, even if no travel is planned.
- Obtain a valid Coggins certificate before any interstate movement, sale, or organized event.
- Ensure your Certificate of Veterinary Inspection (CVI) is issued within 30 days of entry into Montana.
- Obtain an import permit if your CVI is handwritten on paper (not required for electronic CVIs).
- Never transport a horse with a pending EIA test result — wait for a confirmed negative before moving the animal.
- Report any suspected EIA exposure or positive test result to MDOL immediately at 406-444-2976.
Key Insight: The Montana Department of Livestock recommends testing new horse purchases as a top priority, regardless of whether movement is involved. As Montana State Veterinarian Tahnee Szymanski has stated, testing new purchases alongside required interstate movement testing is the best protection against EIA entering your herd.
For more information on Montana’s animal regulations and wildlife, explore our related articles on types of snakes in Montana, types of spiders in Montana, and our overview of fishing license requirements in Montana. For equine enthusiasts, our article on the fastest horse breeds is also worth a read.
Always verify the most current requirements directly with the Montana Department of Livestock before any equine movement, as disease outbreak conditions — such as active vesicular stomatitis cases — can trigger additional temporary requirements on short notice.