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Actinobacillosis
Actinobacillosis is an infection of the soft tissues of the mouth and throat, caused by bacteria that normally lives in the oral cavity of cattle. Its best-known form affects the tongue, which infiltrates, hardens and loses its flexibility:...
What is it?
Actinobacillosis is an infection of the soft tissues of the mouth and throat, caused by bacteria that normally lives in the oral cavity of cattle.
Its best-known form affects the tongue, which infiltrates, hardens and loses its flexibility: hence the popular name “wooden tongue”. The animal is no longer able to grasp its food with its tongue, drools and loses weight.
The disease can also form firm lumps in the lymph nodes and tissues of the head and neck.
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:
Profuse salivation, drool hanging, foam at the lips.
Difficulty grasping food and swallowing, chewing without swallowing, food falling out of the mouth.
Thick, firm and painful tongue, sometimes visible partly outside the mouth: it no longer retracts normally.
Decrease in appetite then rapid weight loss, the animal being hungry but no longer able to eat.
Firm lumps under the skin of the head, throat, or neck, sometimes the size of a bullet, painless at first.
These lumps can break open in the skin and leak a thick liquid containing small yellowish grains.
Head and neck lymph nodes enlarged.
Fall in milk production and loss of body condition when the illness lasts.
In some cases, damage to the back of the throat with difficulty breathing or difficulty ruminating.
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 bacteria responsible, Actinobacillus lignieresii, normally lives in the mouth and rumen of cattle without causing disease.
It only becomes pathogenic after an injury to the mucous membrane: sting by a coarse or spicy food, thistle, ear awn, wire, splinter of wood, hard stem of dry fodder.
Once established in the soft tissues, it causes an inflammatory reaction which gradually hardens the affected area and forms nodules.
Coarse, dry and prickly fodder: hard straw, stubble, poor quality hay, woody stems.
Pastures overgrown with thistles and thorny plants, common at the end of summer when there is a lack of grass.
Presence of foreign bodies in the food distributed: wire, splinters of wood, debris.
Periods of scarcity which push animals to consume plants that they would otherwise abandon.
Mouth injuries related to tooth changes in young animals.
Transmission
There is no direct contagion from one animal to another: the bacteria is already present in the mouths of healthy cattle.
What is shared is the triggering factor: rough or spicy fodder, a pasture invaded by thistles, a batch of food containing foreign bodies. This is why several cases can appear in the same herd, at the same time, without it being a contagious disease.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The veterinarian examines the mouth, palpates the tongue and neck lumps, and assesses the animal's condition.
The key point of its examination is to distinguish actinobacillosis, which affects the soft tissues, from actinomycosis, which affects the jaw bone, and to rule out other causes of salivation and difficulty swallowing: stuck foreign body, injury, dental damage, general illness.
A sample of fluid from a lump may be examined to confirm the diagnosis.
Any abundant and sudden salivation in a bovine must be the subject of rapid veterinary advice, because other important diseases begin in this way.
Treatment
Classic treatment is based on the administration of iodine compounds under veterinary supervision, often combined with an antibiotic. The conduct of the treatment, its duration and the monitoring of the effects are entirely the responsibility of the veterinarian.
The largest or oldest lumps may require surgery, especially when they interfere with breathing or eating.
During treatment, the animal should receive easy-to-eat, moist food without spicy elements, with permanent access to clean water.
Monitoring of body condition is necessary: an animal that is no longer able to eat loses weight very quickly.
Iodine compounds should never be used on your own initiative: if used incorrectly, they are toxic, and they are contraindicated in certain situations, particularly at the end of gestation.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Avoid feeding excessively dry, coarse or pungent forages, and moisten very dry forages when possible.
Control thistles and thorny plants in pastures, particularly those used at the end of the dry season.
Check the absence of foreign bodies in the food distributed: wire, staples, splinters of wood.
Ensure a sufficient ration to prevent animals from falling back on hard plants due to lack of food.
Immediately examine any animal that is drooling, chewing or refusing to eat: treated early, a case can be resolved much more simply.
Possible complications
Severe weight loss due to inability to eat, which can lead to the death of the animal if nothing is done.
Extension of the infection to the throat and back of the mouth, with difficulty breathing.
Recurrence when treatment was stopped too early or the cause, pungent fodder, was not corrected.
Involvement of the rumen or other organs in rare extensive forms.
Culling of animals that are still young when the tongue remains poorly functional for a long time.
When to see a veterinarian
A bovine drools profusely, chews without swallowing or drops food.
Their tongue appears thick, hard, or protrudes from the mouth.
A firm lump appears under the skin of the throat, cheek, or neck.
The animal loses weight quickly even though it seems hungry.
A lump opens and releases a thick liquid.
The animal has difficulty breathing or makes noise when breathing: call immediately.
Prognosis
If caught early, actinobacillosis generally responds well to treatment: the tongue regains its flexibility and the animal begins to eat again within a few days to a few weeks.
Older forms, with hardened and expanded tissues, heal less well and can leave lasting discomfort.
Correcting the forage in question determines the absence of new cases in the herd.
Frequently asked questions
Is it contagious to other cows?
No, not in the usual sense. The bacteria is already present in the mouths of healthy cattle and only causes disease after injury. If several animals are affected at the same time, it is the spicy fodder or thistle pasture that must be blamed, not a contagion.
What is the difference with the “big jaw”?
Big jaw, or actinomycosis, affects the jaw bone, which becomes permanently deformed. Actinobacillosis affects soft tissues, tongue and lymph nodes. The two look similar from a distance but are not treated in the same way, hence the importance of the veterinary examination.
Can I pierce the lump myself?
No. Carelessly opening a lump spreads the infection to nearby tissues and delays healing. Some masses sit near important vessels. This gesture, when it is useful, is done by the veterinarian.
Are milk and meat edible during treatment?
Withdrawal periods apply to medications used. They depend on the products prescribed and must be requested from the veterinarian at the time of the prescription, then strictly respected.
References
FAO — Organisation des Nations unies pour l'alimentation et l'agriculture
Content reviewed by the TunisieVet editorial team · Updated 09 August 2026
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