Hypoglossal Nerve Paralysis in Cows: Tongue Weakness and Feeding Problems

Hypoglossal nerve paralysis means the tongue is weak or partly paralyzed because cranial nerve XII is not working normally. This nerve supplies the muscles that move the tongue. When it is injured or inflamed, a cow may not be able to pull feed into the mouth, move feed around well, or swallow efficiently.

Veterinary references often use the term glossoplegia for tongue paralysis. In cattle, this problem is uncommon, but it matters because normal tongue motion is essential for grazing, prehension, cud chewing, and drinking. Affected cows may look messy when eating, drop feed, drool, or hold the tongue oddly to one side.

Some cases are temporary and improve as swelling or inflammation settles down. Others last longer if the nerve has been badly damaged or if there is a serious underlying disease affecting the tongue, mouth, or nearby tissues. The key next step is not guessing the cause at home, but having your vet determine whether this is a local tongue problem, a cranial nerve problem, or part of a broader neurologic illness.

The direct cause is damage or dysfunction of the hypoglossal nerve, but the reason that happens can vary. Trauma is one possibility. Injury to the tongue, jaw region, or tissues near the base of the skull can interfere with nerve function. Severe inflammation can do the same thing, especially when swelling affects the tongue itself or the tissues the nerve passes through.

In cattle, veterinary references note that glossoplegia may occur with severe actinobacillosis, often called woody tongue. In those cases, the tongue may become firm, painful, enlarged, and hard to move. Merck also notes that complete tongue paralysis with tip necrosis can occur in some cattle and that outbreaks have occasionally followed viral stomatitis.

Other differentials your vet may consider include oral foreign bodies, abscesses, bite wounds, fractures, toxic or infectious neurologic disease, and less commonly a central nervous system lesion affecting the brainstem where the nerve originates. Because several conditions can look similar from a distance, a cow with tongue weakness should be examined rather than treated based on appearance alone.

Diagnosis starts with a hands-on farm exam and a focused neurologic and oral examination. Your vet will watch how the cow eats and drinks, inspect the mouth and tongue, and check for asymmetry, atrophy, swelling, pain, or tongue deviation. In neurologic exams, the hypoglossal nerve is assessed by inspecting the tongue for atrophy, asymmetry, or deviation and by observing tongue movement during protrusion and drinking.

Your vet will also try to decide whether this is an isolated tongue problem or part of a larger cranial nerve disorder. That may include checking swallowing, gag response, facial symmetry, mentation, temperature, hydration, and signs of systemic illness. If the tongue is enlarged, firm, ulcerated, or painful, your vet may prioritize oral disease such as actinobacillosis, trauma, or infection over a primary nerve lesion.

Depending on the case, additional testing may include bloodwork, oral examination under sedation, ultrasound of soft tissues, culture or sampling of suspicious lesions, and in referral cases, advanced imaging or cerebrospinal fluid testing. The goal is to identify the underlying cause, estimate whether recovery is likely, and build a feeding and hydration plan that matches the cow's condition and production role.

Not every case can be prevented, because some arise from unpredictable trauma or deeper neurologic disease. Still, prevention focuses on reducing tongue injury, controlling oral infections, and catching feeding problems early. Check cattle regularly for drooling, feed dropping, foul breath, oral swelling, and changes in cud chewing. Early veterinary attention for mouth pain or tongue enlargement can prevent a small problem from becoming a feeding crisis.

Good feed and facility management also matter. Reduce exposure to sharp foreign material in hay, bunks, and pastures. Handle the head and mouth carefully during procedures, and avoid unnecessary traction on the tongue. If a cow has had recent oral trauma, swelling, or a difficult handling event, monitor eating and drinking closely for the next several days.

Work with your vet on herd-level prevention of infectious oral disease where relevant, including biosecurity, vaccination planning when appropriate for your region, and prompt isolation of animals with suspicious mouth lesions. In cattle with severe actinobacillosis or other tongue disease, early treatment may lower the risk of lasting dysfunction. Prevention is really about fast recognition and cause-specific care, not one universal step.