Ok, I registered just to reply to this thread because you guys have a pretty big misconception about this video and what these grinders are for.
These ANIMALS ARE DEAD. Period. Anybody you says so has been falsely informed or is just lying to shock you.
There are thousands and thousands of farms in America and animals die from disease and complications that are completely natural. These dead animals must be disposed of. Burial is not an option for various reasons mainly because it's a waste of time, space, and useful things that can be harvested from a dead animal. But mainly because there is a large industry that removes carcasses for farmers for a fee and then takes a hazardous and horrifically smelling animal to somewhere it can be used (It's win/win). BTW this includes all sorts of farmers, even ones that do not harvest livestock for meat etc.
These animals are towed into special trucks and take to rendering plants that will determine whether the cow should be dealt with. They will use every single part of the animal for various things including the hide and bones. Sometimes if the animal is sick with dangerous diseases to both human and animal alike they will just grind them up as shown in these videos. This is an important facet of American farm life. Death happens and yes it's disgusting and some people have disgusting jobs. These jobs are important and should be applauded because somebody has to do it.
Trust me, this is the prettier route then letting a dead cow rot in the open. Hell, a bloated cow can explode sometimes. Theres a reason that in medieval times they would throw dead cows with catapults into an enemy castle, disease.
Anyway don't get the impression that the machines or people in these videos don't care about or would harm animals. They are doing a job that is very much necessary and yields many benefits to all people.