Dairy cow with warts

What to look for

  • Hard crusty lesions on the skin 
  • Commonly on the head, neck and shoulders
  • Vary greatly in size
  • May become infected
  • Can be painful if occur on teats of cows or the penis of bulls

Caused by

A viral infection (Bovine Papilloma Virus).

Animals likely to be affected

More commonly seen on animals less than 2 years of age but can occur at any age.

Other diseases with similar signs

Other skin diseases of cattle including ringworm, photosensitisation or dermatophilosis. Animals with warts may also suffer from ringworm at the same time.

How it is spread

Wart viruses are very resistant to drying and disinfectants and so persist on cattle and in their environment. They are spread by contact with infected animals. The virus enters the body through small breaks in the skin. On occasion the disease may be spread by needles or ear tagging instruments if used for successive animals without thorough cleaning.

Risks to people

Warts in people are caused by a different virus and bovine warts do not represent a public health risk.


While warts may be unsightly they cause little harm and there is no need to treat warts unless the location is causing pain e.g. warts on teats of lactating cows or on the penis of working bulls. Supportive treatment with topical antiseptics may be useful if the warts are ulcerated or bleeding. In some cases it may be desirable to remove the warts surgically. Bovine warts usually resolve within a month or two but sometimes last longer.