We always used an electric dehorner on calves, and that works great honestly, probably the best system, for reliability and least amount of pain and suffering for the calf, except while being dehorned. You need a good hot "dehorning iron" the right size to fit around the horn (I assume it would work on a larger horn too... you'd just need a larger diameter iron). We always used an electric one (thermostatically controlled and most reliable for stable required temp). IF it's not hot enough, it for sure won't do the job right... and "red hot" is about right. Apply till you see an orange ring on the hide all the way around the horn, after doing a few, you'll begin to recognize it right away. If you remove the dehorner too soon and don't see that ring all the way around, reapply for a few more seconds (like another 5-10 maybe) and check again. The whole process should only take about that long of application (5-10 seconds) for each horn. You need that head restrained so you can keep the iron firmly on the horn all the way around consistently, and then "rotate" the iron back and forth around the horn a bit too to ensure full contact all the way around... We did maybe 100-130# calves by just 2 guys laying on them to hold them still (we normally did things mostly with brute strength rather than having a piece of equipment to make it easier), any bigger though, and you'll probably want a calf chute with head restraint.
We also have used alot of the elastrator bands to take them off, and they do work well too... when they work. They'll ALWAYS do the job, if they stay put where you want them (so you have to have bigger critters for them to work). With a sharply tapered horn, it's hard to get them to stay put though... they tend to want to roll back up off the horn. You need to get them ALL the way up into the hairline, above the base of the horn, so it "seats" deeper than the horn itself, into the softer tissue there, if you want it to stay. And that's hard to accomplish, especially with large diameter tapered horns. I've taken to putting just slight cuts in the horn surface up there, just ahead of the band on opposite sides of the horn, so it "takes" into that small groove... seems to work pretty well. Results in some bleeding, but with that band placed there, that acts as a tourniquet and shuts the blood down pretty quickly, so nothing to worry about.
Best method of course is to breed for polled heads!
