um, no they're not.
Excuse you, I have done research and projects on this, and I know it for a fact. So leave your proof-less opinions to yourself. Thanks.
And, just so I don't sound like a total jerk, let me say it in a different way. Most McDonald's hamburgers do have a little cow waste in them, it is just a simple fact. It is also why it is very important to order hamburgers cooked well, because that kills all the germs that are in the cow waste.
Angus, among other burgers, are not so much as risk because the meat is from a different part of the cow.
Now, for future reference, next time you post a comment saying something, do a little research.