Cattle Rustling?

I just read an article about a cattle rustler. A real, live (for now) cattle rustler. Now I've lived in places where people have been convicted of bootlegging (that was the actual charge for going into Arkansas to "smuggle" Coors beer back into TN years ago, although I have no idea why anyone would want THAT particular beer that badly). In TN it recently became illegal to have "sexual relations" with animals (I didn't even know that was an option until it was illegal). But I have never lived anywhere that there was a problem with cattle rustling. I asked a co-worker of mine about this, and he said that they've had cattle stolen, or is it "rustled"? That it's really not that uncommon in areas with a lot of livestock. He said that their bull was rustled and there was no way to tell for sure that it was theirs since they had an ear-tag on it and the bull that they saw (their bull) had a conveniently placed chunk taken out of his ear. Ok, I'm a techie and not a farmer in any sense of the word. But do they have RFID tags that they can use for cattle? I'm sure it's a little pricey, but more than likely it's less than the cost of a new cow. I suppose that I could very possibly just be ignorant regarding these things (ok, I really am) but I would have thought rustling went out decades ago. By the way, is that still punishable by death in Tennessee? I believe it is in Texas.