Bovine Papillomatosis in Cows: Warts, Causes, and Treatment

Bovine papillomatosis is a contagious viral skin disease of cattle that causes papillomas, also called warts. These growths are usually benign, meaning they are not cancer, and they can appear as smooth nodules, rough cauliflower-like masses, or stalked growths on the head, neck, shoulders, eyelids, teats, and other skin surfaces. Some cattle also develop lesions on mucosal tissues.

The condition is caused by bovine papillomaviruses, a group of hardy DNA viruses that can spread through direct contact and contaminated equipment or surfaces. Young cattle are affected most often, likely because their immune systems are still developing and they are more likely to have small skin abrasions that let the virus enter.

In many cases, the biggest issue is appearance rather than illness. Still, location matters. Warts on teats can make milking difficult, create pain, and increase the chance of secondary infection. Large clusters around the eyes, mouth, or feet can also interfere with normal function.

Most cases improve with time, but not every case should be watched and waited. If lesions are growing quickly, bleeding, getting infected, or affecting production, your vet can help decide whether conservative care, removal, or additional testing makes the most sense.

Bovine papillomatosis is caused by infection with bovine papillomavirus, often shortened to BPV. Different BPV types tend to affect different tissues, which is why some cattle develop smooth teat nodules while others develop larger fibropapillomas or more widespread skin lesions.

The virus usually enters through tiny breaks in the skin. That means rubbing, tagging, rough fencing, biting flies, milking equipment irritation, and other minor trauma can all make infection more likely. Direct contact with infected cattle is a common route, but indirect spread also matters because papillomaviruses are stable in the environment.

Shared halters, nose tongs, clippers, ropes, milking equipment, and contaminated housing surfaces may help move the virus through a group. Herd spread is more likely when cattle are crowded, stressed, or have poor skin condition. Young animals are affected most often, though adults can also develop lesions.

Most papillomas stay benign. However, chronic irritation, lesion location, and the specific virus type can influence how serious the case becomes. Your vet may be more concerned when lesions are persistent, widespread, or affecting the teat end, because those cases can have a bigger impact on comfort and production.

Your vet will usually start with a hands-on exam and the appearance of the lesions. Classic papillomas often have a recognizable look, especially when multiple cattle in the herd have similar wart-like growths. The location, number, texture, and age of the lesions all help guide the next step.

If the growths are typical and not causing major problems, your vet may diagnose presumptive bovine papillomatosis without advanced testing. When lesions are unusual, persistent, ulcerated, or located in a high-impact area like the teats, a biopsy may be recommended. Histopathology can confirm papilloma tissue and help rule out other causes of skin lesions.

In some cases, your vet may submit tissue or swab samples for PCR to detect bovine papillomavirus DNA. This is more useful when the diagnosis is uncertain, when herd-level management decisions matter, or when lesions need to be distinguished from conditions such as ringworm, poxvirus disease, traumatic lesions, bovine viral diarrhea-related mucosal disease, or other teat and skin disorders.

Diagnosis is not only about naming the wart. It is also about deciding whether the lesions are likely to self-resolve, whether they are affecting milk harvest or welfare, and whether treatment should focus on the individual cow, the milking group, or the whole herd.

Prevention focuses on lowering viral spread and reducing skin injury. Because bovine papillomaviruses can move by direct and indirect contact, it helps to clean and disinfect shared equipment, avoid unnecessary sharing of halters and grooming tools, and keep milking equipment functioning well so teat skin is not repeatedly traumatized.

Good housing and handling matter too. Dry, clean environments reduce skin irritation and secondary infection. Limiting overcrowding, controlling flies, and fixing rough fencing or hardware can reduce the small abrasions that let the virus enter. New arrivals should be observed carefully, and cattle with heavy wart burdens may need to be managed separately when practical.

Young stock deserve extra attention because they are affected most often. Balanced nutrition, low-stress handling, and prompt care for skin wounds support normal immune function. If teat lesions are present in heifers or cows entering the milking string, early veterinary input can help prevent bigger milking problems later.

There is no single prevention step that works in every herd. In endemic or recurring situations, your vet may discuss broader herd biosecurity and, in some settings, vaccine options such as autogenous products. The best plan depends on lesion location, herd size, production goals, and how much spread is already occurring.