The warts are contagious in young calves to long yearling but can crop up in older cows. If you were showing or selling as breeding stock it’s bad. If you don’t mind it and it’s not affecting the animal you can let it die out on it’s own but others not showing symptoms may be vulnerable to infection as well as new animals introduced. If you’re able to separate it’s advisable. Disinfect tagging equipment and use separate needles between animals.
There are options. You can cut large warts on the declining stage but be prepared to stop the bleeding with glue or nitrate stick. I remove them by tying clean poly twine to ‘pop’ them off, seems to be less bleeding versus scalpel. Or less messy, Ivermectin on the wart will shrivel them up.
I had an outbreak in a closed herd so it was a surprise to me only affected calves. I have a theory that it showed up via flies from a nearby operation that started buying salebarn cattle to trade.
All were inside ear where I tagged with fly tag. The larger one was about 2 inches. Removed with twine but I have put pour on others with large lumps. The ones with small warts fell off rather easily. I had some calves show zero symptoms so it seems the ones with weaker immune systems will have large warts.
