I've seen rams live a long time after loosing one horn, and in one case I know of both horns. One OR ram I saw had "slipped" both horns, one one year after the other. I watched him for the next 5 years and had actually grew some base back to cover the open bone sections. He was a weird looking old ram I nick named Troll. He died at age 12 one winter.
Lots of times these rams will chip a horn so bad they get an air hole into the core which in turn will cause the membrane to rot on that side. One pop and off it comes with no ill effects to the ram. Some get a sinus infection causing the same result or it causes the horns to become brittle. That could be the case with this ram having been exposed to pasturella during the 1999-2011 die off.
