Necrotic Stomatitis in Cows: Painful Mouth Infection and Feeding Problems

Necrotic stomatitis is a painful inflammatory disease of the mouth in which areas of the oral tissues become ulcerated and die. In cattle, this problem is often associated with secondary bacterial infection, especially when the lining of the mouth has already been damaged by rough feed, erupting teeth, foreign material, or another oral disease. A common bacterium involved in necrotic infections in cattle is Fusobacterium necrophorum, an anaerobic organism that normally lives in the body but can invade injured tissue.

Affected cows may have sores on the gums, cheeks, tongue, lips, or dental pad. These lesions can look raw, gray, yellow, or foul-smelling. Because the mouth is so painful, many cattle drool, chew slowly, drop feed, or stop eating enough. In calves, poor intake can quickly lead to dehydration and loss of condition.

Necrotic stomatitis is not a single look-alike condition. Your vet may also need to rule out other causes of oral lesions, including bovine papular stomatitis, vesicular stomatitis, trauma, chemical irritation, and other infectious diseases. That is one reason a prompt veterinary exam is important when a cow has mouth ulcers or sudden feeding problems.

Necrotic stomatitis usually develops when the protective lining of the mouth is injured first and bacteria invade second. Rough stems, awns, sharp feed particles, wire, splinters, or other foreign material can create tiny wounds. Teething calves may also have irritated oral tissues that are easier for bacteria to invade. Once the tissue barrier is broken, bacteria such as Fusobacterium necrophorum can multiply in the low-oxygen environment of damaged tissue.

Other mouth diseases can set the stage as well. Viral or parapox lesions, chemical burns, and trauma may all leave the mouth vulnerable to secondary necrotic infection. Merck notes that F. necrophorum is a normal inhabitant of cattle and acts as an opportunistic pathogen in necrobacillosis, meaning it often takes advantage of preexisting tissue injury rather than causing disease in healthy tissue on its own.

Risk can increase with crowding, stress, poor nutrition, abrupt feed changes, and environments where cattle are exposed to coarse forage or contaminated feeding areas. Calves and young stock are often more vulnerable because they are still growing, may be under immune stress, and can decline quickly when mouth pain interferes with eating.

Your vet usually starts with a full history and careful oral exam. They will look for ulcers, dead tissue, odor, swelling, foreign material, and signs of dehydration or fever. In many cases, the appearance and location of the lesions, along with feeding difficulty and drooling, strongly suggest an oral infection with tissue necrosis.

Diagnosis also means ruling out other causes of mouth lesions. In cattle, that can include traumatic injury, bovine papular stomatitis, vesicular stomatitis, malignant catarrhal fever, bovine viral diarrhea-related oral disease, and other infectious or toxic causes. Because some oral diseases in cattle have regulatory importance, your vet may recommend isolation precautions until a more serious contagious disease is excluded.

If the case is severe, unusual, or not responding as expected, your vet may collect samples for cytology, culture, biopsy, or additional laboratory testing. They may also assess hydration status, body condition, and whether the infection appears limited to the mouth or has spread into deeper tissues. That information helps your vet match treatment intensity to the individual cow.

Prevention focuses on reducing mouth injury and lowering bacterial opportunity. Check hay, bedding, fencing, feeders, and pasture for sharp stems, awns, wire, splinters, and other objects that can cut the mouth. Feed management matters too. Abrupt changes to coarse or stemmy forage can increase oral irritation, especially in young cattle.

Good calf and herd management also helps. Keep feeding areas reasonably clean, reduce overcrowding, and support strong nutrition so cattle are better able to heal small oral injuries before they become infected. Watch teething calves and recently stressed animals closely, because they may be more likely to develop feeding problems after minor mouth trauma.

Prompt attention to early drooling, bad breath, or slow eating can prevent a small lesion from becoming a deeper necrotic infection. If one cow develops oral sores, ask your vet whether isolation or additional herd checks are appropriate. That is especially important when lesions are widespread, blister-like, or accompanied by other signs that could suggest a contagious disease rather than a simple traumatic mouth infection.