No, they'll go away one their own. Or you can crush one and make it bleed, or take one off and feed it to him or take one off and buried it in a dirty wash cloth under your neighbors sisters mother in laws cousins porch. It all works about the same.
I believe Dunn is correct. However, should you like to take other action;
1 Pull some of the warts off with pliers...making them bleed. This apparently sets up antibodies.(It is recommended to wear gloves and keep things sterile...starting with purple spray on the area before procedure)
2 Give a vacinnation of ...Killed Wart Vaccine(from your Vet)...and another 10 days later.
Around here animals with warts are discounted. :frowns:
We've got them this year on our spring 08 steers and heifers for the first time in ages. They are for the most part harmless, but UGLY. There's good info on the net that ought to ease your mind. Start here: http://cattletoday.info/warts.htm