Joe I have made plenty of cow horn calls,but they were the type used when hunting with dogs that run animals.and we used them to call the dogs and talk to each other in the jungles.have not made one for yotes yet.to time consuming for me right now.as I have a million and one things going on when I am not at work.I have called in several coyoyes with my mouth.But it hurts my lips after a while.and find several calls on a lanyard around my neck works fine.I have made calls out of differnt bullet cases.and they work great.But since I found this article..I beleive I am going to try and make a cow horn call.all I need now is some cow horns..that should not be easy to find.