Bovine Herpes Mammillitis in Cows

Bovine herpes mammillitis is a viral skin disease that affects the teats and udder of cattle. It is most commonly associated with bovine herpesvirus 2 (BHV-2) and is also called bovine ulcerative mammillitis. The disease causes painful skin lesions that can begin as swelling or small raised plaques, then progress to blisters, ulcers, and thick scabs.

This condition matters because cows with sore teats may resist milking, kick during handling, or produce less milk. Open skin also creates an easier path for bacteria, so some cows develop secondary mastitis along with the viral lesions. In herd settings, spread can happen through direct contact and through milking equipment or hands if hygiene slips.

Many cows recover with time and supportive care, but healing can take several weeks. Even after the visible sores improve, herpesviruses can remain in the body and reactivate later during stress. That is one reason herd management and prevention are such important parts of care.

The usual cause is bovine herpesvirus 2 (BHV-2). This virus infects the skin of the teat and udder and can spread between cattle by direct contact, contaminated milking equipment, and hands or towels used from cow to cow. Skin trauma can make infection easier, so rough milking conditions, chapping, or irritation may increase risk.

Stress also seems to matter. Fresh cows and heifers can be hit harder, likely because udder skin is more stretched and vulnerable around calving and early lactation. Like other herpesviruses, BHV-2 may remain latent in the body after infection and reactivate later, especially during stressful periods.

Not every teat sore is herpes mammillitis. Your vet may also consider pseudocowpox, bovine papular stomatitis, trauma, photosensitization, bacterial dermatitis, mastitis-related teat damage, vesicular stomatitis, and other causes of ulcerative teat lesions. That is why a careful exam and, in some cases, lab testing are important.

Diagnosis starts with a herd and cow-level history plus a close look at the lesions. Your vet will note where the sores are located, whether they began as blisters or plaques, how many cows are affected, and whether there are signs of mastitis or milk loss. The appearance can strongly suggest herpes mammillitis, but several other diseases can look similar.

Because some look-alike conditions are serious or reportable, your vet may recommend testing. Depending on the case, samples can include lesion swabs, crusts, or tissue for virus testing, along with milk samples if mastitis is suspected. Older reports describe diagnosis by virus isolation and serum-neutralization testing, and veterinary diagnostic laboratories still offer BHV-2 serology in some settings.

If lesions are unusual, severe, or not healing as expected, your vet may also pursue bacterial culture, cytology, or biopsy to rule out secondary infection and other skin diseases. The goal is not only to name the cause, but also to guide practical herd management and milking decisions.

Prevention focuses on limiting spread and protecting teat skin. Good milking hygiene matters: clean and dry teats appropriately, use gloves, avoid sharing towels between cows, and disinfect equipment as recommended for your system. Cows with active lesions are often best milked last so virus and bacteria are less likely to move through the herd.

Reducing teat trauma also helps. Check liners, vacuum settings, overmilking risk, bedding cleanliness, weather exposure, and any rough handling that could damage skin. Chapped or injured teats are more vulnerable to infection and slower to heal.

Because herpesviruses can persist in the body, stress reduction is part of prevention too. Fresh cows deserve close observation, since early lactation animals may show more severe disease. If new teat lesions appear in several cows, involve your vet quickly so the herd can get a practical control plan and important differentials can be ruled out.