I once pulled 2 old slugs out of an Elk Cow I took down. Cut out the meat around each slug, it looked like a little bit of a funky healing anyway. So I wouldn't be surprised if the copper came from your animal, although I wouldn't be surprised if you weren't getting your same animal back from the butcher. (Don't know Steve's, just saying shit happens) I've always butchered my own, but there is a guy in Springer, NM who does great work. Wife got a cow given to her by a friends dad who guides at a local ranch. He had already dropped it off at the guy in Springer, so I had to pay processing fee's if I wanted the meat. Kinda pissed me off. "Here's some free meat, so pay this guy a couple hundred bucks" but in the end, it was nice to get some cheap elk meat.

Of course the guide did take the tenderloin out for himself. Oh well, still I only payed about $1.50/LB for good meat.