Must be killing new born calves. I don't see them able to kill a cow or a calf that has been around for a few days.
Fresh newborns are the most vulnerable targets. Usually if a calf is born in the early night he will be up and going enough to be out of danger. The black headed smaller vulture is the culprit. The turkey buzzard not so much. In our area if action is not taken a herd will be constantly threatened by vultures. They are vicious and you will find 30 or 40 surrounding a cow with a new calf. The cow ends up trampling the calf while fighting buzzards. They can be convinced to stay away, although that lesson has to be reinforced from time to time. Next biggest problem is the neighborhood dogs wanting to pack up and resume their ancestral behavior. There is only one solution to that.
