Fact Checked

What Causes Warts on Cows?

Jennifer Mackin
Jennifer Mackin

The bovine papillomavirus (BPV) has six different strains that can cause warts on cows. The strains are characterized into six groups, BPV 1 through BPV 6. Warts on cows are caused by a virus strain, so they are infectious. This virus can be transmitted only to other cows — people cannot be infected.

Warts can occur on any part of the cow’s body. The location of the warts can help determine which type of wart the cow has contracted. BPV 1, BPV 5 and BPV 6 strains can cause warts on the cow’s reproductive organs or teats, and BPV 2 and BPV 3 warts are located on the head and neck. The BPV 4 strain can cause warts to grow in gastrointestinal tract.

Warts on cows are typically found on those that are two years old or younger.
Warts on cows are typically found on those that are two years old or younger.

Open wounds can allow the papillomavirus to enter the cow’s body if it comes into contact with another infected cow or contaminated farming equipment. Certain insects also carry the virus and can infect the cow if it’s bitten. The incubation period can last from one month to one year. Warts on cows are mostly found on those that are two years old or younger. Older cows build a natural immunity to the virus.

The appearances of the warts vary from strain to strain. Some warts are flat. Others resemble a cauliflower cluster that protrudes from the skin, and others are long, white lesions. If one cow has warts, then the entire herd most likely will have them. All cows are susceptible to the virus.

For the most part, warts on cows rarely cause actual physical problems. In rare cases, warts can spread to the reproductive organs of the cow and cause pain, keeping breeding cattle from reproducing. Dairy cows can grow warts on their teats. Milking can become painful, which can affect milk production. Unless the warts affect productivity, the warts usually are left untreated.

Purebred or show cattle dealers can suffer the most when warts infect their cattle. The presence of the warts makes it almost impossible for the dealers to get disease-free health papers on the herd, making future sales difficult until the warts are gone. A lot of cattle dealers will treat warts on cows by surgically removing them.

Commercial vaccination is an option, but if the herd has ever had an outbreak of any type of wart, then the probability that the vaccination will work is significantly decreased. If warts have not been an issue within the herd, vaccinations can help prevent warts from happening. The vaccinations usually are given in two injections three to five weeks apart.

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Discussion Comments


@SarahGen-- I heard that if a wart on a cow is squeezed or crushed, the cow's immune system responds to it and fights the virus. But I don't know if this is safe to do and it might cause pain. So check with a vet before doing something like this. The reason I mention it is because I have heard the same tip from multiple people. They all claimed that it works.


@SarahGen-- If the teats are not affected, warts can be left alone. It might take a while but the wart will eventually go away. Don't be surprised if it grows bigger.

I think that treatment is a good idea for warts is if the rest of the herd isn't affected or if you're sending a cow to a herd that has warts. Vaccination is a good idea in these cases.

Treatment might be necessary if the teats are affected and if the wart causes pain for the animal like the article said.


I noticed today that one of my cows has a wart above her eye. She doesn't seem to be bothered by it and I haven't seen warts anywhere else on her. Do I need to do anything for this or should I just leave it alone?

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    • Warts on cows are typically found on those that are two years old or younger.
      By: Margo Harrison
      Warts on cows are typically found on those that are two years old or younger.