. >> we want our rye nhino to las long as possible. we want to be able to harvest horns as much as we can. >> reporter: many farmers say it's a no-brainer. even those like lynn mccalfish who once opposed it, has changed her mind. >> i will never get over it. >> critics dehorning min dehorning means you want to make money. >> dehorning is the last resort. we've got our backs up against the wall now. >> reporter: but dehorning entails a new threat. >> the minute the horn comes off the animal, the risk is immediately. >> reporter: you have weapons, everything else for protection. >> so everyone is armed. >> reporter: a young calf is up first. they dart it right away. but the mother needs a second dose. niko comes in for the dart and off they go. the horns are cut and sanded. leaving behind only a couple of inches. so it can regrow. >> it looks almost like, it's the same as if you were cut your nails. it has keratin in it. >> reporter: and just like the fingernails, the horn grows ba supply of a commodity more valuable than gold. >> we are