I gave one of my dogs those big cow femers(sp?). Once she got the knuckles chewed down to the bone she started breaking off sharp chunks of bone and she was chipping her teeth. I've seen the same thing with the rescue dogs at adoptions with the cow hooves. They love those things, but when they start breaking them into sharp little pieces I have to question how safe they really are. I've had to pull some of those pieces out of their mouths, so they would swallow them if given the chance, then you may end up with some big problems. I would probably have the same worries about deer antlers. I prefer rawhides, they still clean teeth and don't splinter. But that's me.