Brucellosis Testing Protocol for Natural Breeding: What Every Dog Owner Must Know

Brucellosis can silently destroy a breeding program — and it is transmissible to humans. Testing before every natural breeding is non-negotiable.

Brucella canis is a bacterial infection that causes reproductive failure in dogs — abortions, stillbirths, failed conceptions, and infertility. It spreads through contact with reproductive fluids during mating, whelping, or after abortion. It can infect humans. And it has no reliable cure in dogs — an infected dog is infected for life.

For any natural tie, testing both dogs beforehand is the minimum standard of responsible breeding. This guide covers exactly what that testing looks like, when it must be done, and what questions to ask before agreeing to any breeding.

What Is Brucella Canis?

Brucella canis is a gram-negative bacterium that infects the reproductive tract of dogs. Unlike many infectious diseases, infected dogs may show few or no obvious symptoms — meaning a dog can be a carrier and source of infection while appearing completely normal.

In infected females:

• Abortion in the last trimester (often the first sign)
• Delivery of stillborn or weak puppies
• Failure to conceive despite normal mating and timing
• Vaginal discharge (often the most visible sign)
• Infertility

In infected males:

• Infertility or reduced fertility
• Testicular swelling, then shrinkage and atrophy over time
• Enlarged lymph nodes near the groin
• Prostatitis
• Often no outward symptoms for extended periods

Systemic signs in both sexes:

• Lethargy, weight loss, back pain (if spinal infection develops)
• Swollen lymph nodes
• Often subclinical — no visible symptoms

Transmission

Brucellosis spreads primarily through:

• Natural breeding (the highest-risk event) — direct contact with vaginal secretions, seminal fluid, and prostatic fluid
• Contact with aborted material — fetal tissue and fluids carry extremely high bacterial loads
• Whelping — birth fluids can transmit to other dogs in a kennel
• Contact with urine — infected dogs shed the bacteria in urine

It is zoonotic — meaning it can infect humans. Human brucellosis from B. canis is less severe than brucellosis from other Brucella species, but it causes persistent flu-like illness, fever, and can be difficult to treat. Immunocompromised individuals face higher risk.

The Testing Protocol

The standard minimum protocol for natural breeding:

• Both the stud dog AND the dam must be tested
• Testing should be completed within 30 days before the breeding
• Both dogs must test negative before any breeding takes place

Testing within 30 days is critical because Brucella can be acquired at any time — a dog that tested negative six months ago could be positive today if it has had contact with infected animals.

Types of Brucellosis Tests

Rapid Slide Agglutination Test (RSAT) The most common initial screening test, available at most veterinary clinics from a blood sample. Fast (results in minutes to hours), inexpensive (~$20-40), and sensitive — meaning it catches most positive dogs. However, it has a relatively high false-positive rate.

Tube Agglutination Test (TAT) / 2-Mercaptoethanol TAT (2ME-TAT) A confirmatory blood test that reduces false positives. If the RSAT is positive, a 2ME-TAT is typically performed to confirm.

AGID (Agar Gel Immunodiffusion) A highly specific confirmatory test with very few false positives. Considered the gold standard for confirmation of positive screening results.

PCR Testing Newer molecular test that detects bacterial DNA directly. Can be run on blood or other samples. Highly specific and sensitive. Increasingly used as a first-line test or confirmation.

Culture The definitive test — growing the actual bacteria from a sample. Highly accurate but requires specialized laboratory facilities and biosafety precautions. Used primarily in research and outbreak investigation.

Interpreting Results

Negative result on RSAT (or PCR): The dog is almost certainly free of Brucella canis. Proceed with breeding.

Positive result on RSAT: Do not breed. Run confirmatory testing (2ME-TAT or AGID) immediately. Many RSAT positives are false positives, but the dog must be confirmed negative before any breeding.

Positive on confirmatory testing: The dog is infected. Do not breed. Consult a veterinarian immediately about management. There is no reliable cure — most infected dogs require spaying or neutering and lifelong isolation from other breeding dogs.

What to Ask Before Agreeing to a Natural Tie

Whether you own the stud or the dam, these questions should be asked and answered in writing before any natural breeding:

If you own the dam:

1. Has the stud been tested for Brucella canis within the last 30 days?
2. Can you provide written documentation of the test result (clinic name, date, result, veterinarian signature)?
3. Has the stud had contact with any other dogs (particularly females in heat) since testing?

If you own the stud:

1. Has the dam been tested for Brucella canis within the last 30 days?
2. Can you provide written documentation?
3. Has the dam been exposed to any other dogs or kennels since testing?

No responsible stud owner should allow a natural tie without documentation of a current negative test on the dam. No responsible dam owner should agree to a natural tie without the same for the stud.

Include Brucellosis Testing in Your Stud Contract

A well-written stud dog contract should explicitly require:

• Proof of negative Brucella canis test within 30 days for the dam
• The stud owner's commitment to maintain a current negative test on the stud
• Agreement that either party may cancel the breeding if either dog tests positive

This protects both parties and creates a clear standard that prevents disputes.

Brucellosis in a Kennel: A Catastrophic Scenario

If Brucellosis enters a kennel environment, the consequences are severe:

• All dogs in contact must be quarantined and tested
• Infected dogs cannot be cured reliably and must be removed from the breeding program
• All surfaces, bedding, and whelping equipment must be thoroughly disinfected
• The kennel may need to be closed to outside dogs indefinitely

Prevention through pre-breeding testing is infinitely easier and less costly than managing an outbreak.

Summary

Brucellosis is a contagious, incurable bacterial disease that causes reproductive failure and can infect humans. It spreads primarily through natural breeding. Both the stud and dam must be tested within 30 days before any natural tie, with negative results documented in writing. The RSAT is the standard screening test; confirmatory testing follows any positive screen. Include Brucellosis testing requirements in all stud contracts. There is no substitute for testing — a normal-appearing dog can be infected and contagious. Test every time, without exception.