Actinobacillosis in Cows: Wooden Tongue Symptoms and Care
- Actinobacillosis, often called wooden tongue, is a bacterial infection of soft tissues in cattle most commonly caused by Actinobacillus lignieresii.
- Typical signs include a hard swollen tongue, drooling, trouble grasping feed, pain when the tongue is handled, and swelling under the jaw.
- See your vet promptly if your cow is not eating well, is losing weight, or has tongue or facial swelling. Early treatment often improves the outlook.
- Your vet may diagnose it based on the exam, but culture or biopsy can help confirm the cause and rule out other oral diseases or masses.
- Common treatment options include sodium iodide given by your vet, supportive care, and in some cases antibiotics or drainage of abscesses.
What Is Actinobacillosis in Cows?
Actinobacillosis is a bacterial infection of soft tissues in cattle, most often caused by Actinobacillus lignieresii. The best-known form is wooden tongue, where the tongue becomes firm, swollen, and painful. Even though the tongue is the classic site, this infection can also affect nearby soft tissues of the mouth, lips, cheeks, throat area, skin, or lymphatic tissues in the head and neck.
The bacteria are usually part of the normal flora of the upper digestive tract. Problems start when they enter tissue through small wounds, often after rough forage, stemmy hay, thorns, or other abrasive feed materials irritate the mouth. Once inside, the bacteria can trigger pyogranulomatous inflammation, which creates firm nodules, swelling, and thick pus.
Wooden tongue is usually sporadic, but herd-level problems can happen when multiple cattle are exposed to coarse, irritating feed. The condition is not usually thought of as highly contagious in the way some respiratory or diarrheal diseases are. Instead, it is more often linked to tissue injury plus bacterial invasion.
The good news is that many cows improve well when the condition is recognized early and treated quickly. Cases limited to the tongue often respond dramatically within about 48 hours after sodium iodide treatment from your vet, while more extensive or chronic soft-tissue disease may need a longer and more involved care plan.
Symptoms of Actinobacillosis in Cows
- Firm, hard, swollen tongue
- Excessive drooling or ropey saliva
- Difficulty grasping or chewing feed
- Pain when the mouth or tongue is handled
- Tongue protruding from the mouth
- Swelling under the jaw or between the lower jaws
- Weight loss or reduced body condition
- Reduced appetite or slower eating
Call your vet sooner rather than later if your cow has tongue swelling, drooling, trouble eating, or swelling under the jaw. These signs can fit wooden tongue, but they can also overlap with trauma, abscesses, foreign bodies, oral masses, vesicular diseases, or other infections. A cow that cannot eat normally can decline quickly.
Urgency goes up if the tongue is hanging out, the cow is losing weight, breathing seems harder, or there is widespread swelling in the mouth or throat area. Early cases often respond better than chronic ones, so prompt veterinary care can make a meaningful difference.
What Causes Actinobacillosis in Cows?
The usual cause of wooden tongue in cattle is Actinobacillus lignieresii. This bacterium normally lives in the mouth and upper digestive tract of healthy animals. Disease develops when it gets pushed into deeper tissues through a break in the lining of the mouth or tongue.
Common triggers include rough hay, stemmy forage, awns, sticks, thistles, or other abrasive feed materials that create tiny wounds. Once the bacteria enter the tissue, they can cause localized abscesses and granulomatous inflammation. That inflammatory response is what gives the tongue its hard, "wooden" feel.
Not every case stays limited to the tongue. The infection can spread through local lymphatic channels and create swelling or nodules in nearby soft tissues, especially around the jaw, head, and neck. In atypical cases, lesions may show up in other soft tissues and may not involve the tongue much at all.
Herd outbreaks are uncommon but can happen when a group of cattle is exposed to the same coarse or irritating feed source. That is why your vet may ask detailed questions about recent hay changes, pasture conditions, feeding equipment, and whether other cattle are showing oral discomfort.
How Is Actinobacillosis in Cows Diagnosed?
Your vet will usually start with a hands-on oral exam and a review of feeding history, timing, and herd patterns. In classic cases, the combination of a hard painful tongue, drooling, trouble prehending feed, and intermandibular swelling can strongly suggest actinobacillosis.
Even when the signs look typical, confirmation may still matter. Merck notes that diagnosis in cattle requires culture and biopsy of the lesion. Samples can help identify Actinobacillus lignieresii and rule out look-alike problems such as trauma, foreign-body abscesses, neoplasia, actinomycosis, or other oral infections.
Depending on the case, your vet may collect pus or tissue for bacterial culture, cytology, or histopathology. Basic bloodwork is not always very specific for this disease, but it may be useful if your cow is dehydrated, losing condition, or needs a broader workup before treatment.
Diagnosis is also about deciding how severe the case is. Your vet may assess whether the disease seems limited to the tongue, has spread into surrounding soft tissues, or is interfering with swallowing enough to require more intensive support. That staging helps guide which Spectrum of Care option makes the most sense for your herd and budget.
Treatment Options for Actinobacillosis in Cows
Spectrum of Care means you have options. Here are treatment tiers at different price points.
Budget-Conscious Care
- Farm call or ambulatory exam
- Clinical diagnosis based on history and oral exam
- Sodium iodide treatment administered slowly IV by your vet when appropriate
- Short-term feed changes to softer, easier-to-grasp feed
- Monitoring appetite, drooling, and tongue size over 24-72 hours
Recommended Standard Treatment
- Farm call and full physical exam
- Sodium iodide treatment plan with recheck dosing if needed
- Targeted sample collection such as aspirate, culture, or biopsy when lesions are atypical or response is incomplete
- Pain and inflammation management when appropriate and legal for food animals
- Nutrition and hydration support recommendations
- Recheck exam to confirm the tongue is softening and feed intake is improving
Advanced / Critical Care
- Comprehensive veterinary workup for severe, chronic, or atypical cases
- Culture, biopsy, and histopathology
- Repeated treatments and close reassessment
- Drainage or management of associated abscesses when indicated by your vet
- Fluid therapy or intensive supportive care for cows that are dehydrated or not eating
- Broader differential diagnosis workup if oral masses, severe trauma, or other diseases are possible
Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.
Questions to Ask Your Vet About Actinobacillosis in Cows
Bring these questions to your vet appointment to get the most out of your visit.
- Does this look like classic wooden tongue, or do you think another oral condition is possible?
- Is this case mild enough for a conservative treatment plan, or do you recommend culture or biopsy?
- What treatment options fit this cow's condition and our herd budget?
- How soon should I expect improvement after treatment, and what signs mean the plan is not working?
- Does this cow need softer feed, separation from the herd, or extra hydration support during recovery?
- Are there food-animal drug withdrawal times or milk and meat restrictions I need to follow?
- Could rough hay, pasture plants, or feeding equipment be contributing to mouth injuries in this group?
- If more cows develop drooling or tongue swelling, what herd-level steps should we take right away?
How to Prevent Actinobacillosis in Cows
Prevention focuses on reducing mouth injuries. Because Actinobacillus lignieresii is often already present in the upper digestive tract, the key step is limiting the small wounds that let it enter deeper tissue. Check hay, silage, browse, and pasture for coarse, stemmy, thorny, or otherwise abrasive material, especially if you have seen more than one cow with oral discomfort.
Feed management matters. Avoid sudden switches to rough, poor-quality forage when possible, and inspect bunks, fencing, and feeding equipment for sharp edges that could injure the mouth. If a herd problem appears after a feed change, talk with your vet and nutrition team about whether that forage source should be replaced.
Because wooden tongue is usually sporadic, there is no routine vaccine used for prevention. Early detection is often the most practical herd-level tool. Watch for drooling, slower eating, feed dropping, or swelling under the jaw, and have affected cattle examined before weight loss becomes significant.
If one cow is diagnosed, it is reasonable to review the whole group for similar signs and to look closely at the current ration and environment. Prompt treatment of early cases and correction of abrasive feed risks can help reduce additional cases.