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Bovine genital campylobacteriosis
Bovine genital campylobacteriosis is a venereal disease of cattle: it is transmitted during mating. The responsible bacteria settles in the female's genital tract and prevents the embryo from surviving. The cow doesn't look sick. What the b...
What is it?
Bovine genital campylobacteriosis is a venereal disease of cattle: it is transmitted during mating. The responsible bacteria settles in the female's genital tract and prevents the embryo from surviving.
The cow doesn't look sick. What the breeder notices is a herd that is not taking: females mated several times, heat that returns at irregular intervals, a breeding season that is stretched out and a number of calves significantly lower than expected.
The bull is the silent reservoir of the disease: it carries the bacteria in the folds of its sheath without ever showing the slightest sign, and contaminates the females with each mating. It is a disease listed by the World Organization for Animal Health.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Related signs — each one links to its page:
In females: infertility, repeated returns to heat, often at long and irregular intervals.
Breeding season spreads out abnormally, calves born late and in a scattered manner.
Marked drop in the pregnancy rate at the herd level: this is the main warning sign.
Discreet vulvar discharge in some cows, often unnoticed.
Abortions, generally few in number and occurring more often at the beginning or in the middle of gestation.
In the bull: no sign. He remains in great shape, his semen appears normal and his libido is not changed.
First-breed heifers, never exposed before, are often the most affected.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
The infection is caused by bacteria that colonizes the genital tract.
In the female, the resulting inflammation of the uterus and tubes prevents the embryo from implanting or causes its early death: the cow comes back into heat as if it had never been fertilized.
In bulls, the bacteria remains on the surface of the sheath without causing any lesions, which explains the total absence of signs.
Use of natural breeding, particularly with older bulls.
Introduction of a bull or females whose health status is not known.
Sharing or loaning bulls between farms, a common practice on small farms.
Herds made up mainly of heifers or females that have never been exposed.
Reproductive material insufficiently cleaned and disinfected between animals.
Absence of reproductive monitoring allowing early detection of reduced fertility.
Transmission
Transmission occurs mainly during natural mating: the carrying bull deposits the bacteria in the female's genital tract.
The bacteria survives for a long time in the folds of the bull's sheath, particularly in older bulls whose folds are deeper. These bulls remain strong for years.
Contamination can also occur through soiled reproductive material, or through semen collected from an infected bull and processed without the required precautions.
An infected female can contaminate a healthy bull, which in turn becomes a source of infection for the entire herd.
Artificial insemination with semen from controlled centers interrupts this chain of transmission.
There is no transmission by simple contact on pasture, nor by water or food.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The diagnosis is not made by eye: it is based on samples and laboratory analyzes carried out by the veterinarian.
In the bull, a sample of the sheath is the reference examination. It must be repeated often, because the bacteria is not found every time.
In females, samples of genital mucus can be analyzed, as well as the aborts and their envelopes when present.
The veterinarian rules out other causes of reduced fertility in the herd: other reproductive diseases, nutritional deficiencies, simply unfit bull, poor heat detection.
At the herd level, reconstructing the dates of mating and return to heat is a key element of the investigation.
Treatment
Treatment is the responsibility of the veterinarian and is based on the scale of the herd, not an isolated animal.
Antibiotic treatments, general or applied locally to the bull's sheath, can be implemented on prescription. Their effectiveness is variable, particularly in older, long-term carrier bulls.
In many situations, the safest solution is to cull the carrier bull(s) and switch to artificial insemination with semen from controlled centers.
Infected females most often end up eliminating the bacteria and regaining their fertility, provided they are not reinfected: hence the importance of first treating the problem at the source.
A period of sexual rest for the herd is sometimes recommended to give females time to clean up.
If drug treatment is used, the withdrawal period for milk and meat set by the veterinarian applies and must be respected.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Favor artificial insemination with semen from controlled centers: this is the most effective prevention measure.
If you use natural breeding, only introduce bulls whose status has been checked, and prefer young bulls.
Avoid loans and exchanges of bulls between farms, as well as mating by a bull from outside the herd.
Isolate and have any newly purchased animal checked before including it in breeding.
Systematically clean and disinfect reproduction and examination equipment between animals, and use single-use gloves.
Monitor the herd's reproduction results: pregnancy rate, number of services per pregnancy, calving spread. A deterioration must trigger an investigation.
In certain countries, vaccines exist for heavily affected farms: the question is discussed with the veterinarian according to local regulations and the situation of the farm.
Possible complications
Long-lasting drop in herd productivity: fewer calves, spread out calvings, heterogeneous batches.
Chronic inflammation of the genital tract in some females, with prolonged infertility.
Numerous reforms for infertility, wrongly affecting healthy but reinfected females.
Diffusion of the infection to other farms through the loan of bulls.
Major economic loss over several breeding campaigns if the carrying bull is not identified.
When to see a veterinarian
Your females come into heat repeatedly after several matings.
The herd's pregnancy rate drops from one campaign to the next.
Calving events are spread out abnormally over time.
Abortions occur, particularly in many females.
You introduced a bull or borrowed an outside bull, and then the fertility deteriorated.
Your first-breed heifers take significantly less well than older cows.
Prognosis
At the individual level, most females spontaneously recover and become fertile again if not re-exposed; however, the delay can reach several months and costs a reproduction campaign.
At the herd level, sanitation is possible but requires action on the source: elimination or treatment of carrier bulls, transition to artificial insemination, control of introductions.
Without intervention, the infection persists from year to year and the losses are repeated.
Frequently asked questions
My bull looks in great shape: can he still be responsible?
Yes, and that's the difficulty of this disease. The carrier bull shows no signs, his semen appears normal and his libido is intact. Only samples from the sheath allow us to know this.
Does artificial insemination really protect?
Yes, provided that the semen comes from a controlled center and that the equipment is clean. This is the most effective measure to cut off the transmission, which is mainly done through the projection.
Can I get this disease from handling my animals?
This genital infection of cattle is not considered transmissible to humans. The usual hygiene precautions, gloves and hand washing, remain recommended when handling the genital tract or an abortion.
Should we cull all the cows that don't take?
No, that would be a costly mistake. Many of these females are healthy and become fertile again once the source of infection is eliminated. The diagnosis must be made before any massive reform decision.
References
WOAH — Organisation mondiale de la santé animale (ex-OIE)
Content reviewed by the TunisieVet editorial team · Updated 09 August 2026
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