This is not a pretty picture, but because we have a choice and can do something about it, I ask that you read the following and discontinue buying feedlot meats. Your dollar is your vote. Ethical and humane farming practices can grow by purchasing food from ethical and humane farmers.
In regards to cattle and bison, their natural diet is and always has been grass. They have four stomachs, the first is the rumen to help them digest the grass.
The following information has been reported from observations of feedlot cattle which are taken off their natural diet and given grains.With the onset of disease, the cure calls for drugs. See the first link below for full story.
But there is another worry that is even worse in our estimation:
The animal grain feed is not pure, safe food anymore. Someone had the bright idea to increase the food supply with "valuable protein" but "valuable" to whom? You be the judge. We choose "Grass Fed" and will leave the "Grain Fed" alone.
"In 1997, the U.S. Food and Drug Administration required that most protein derived from ruminants (cud-chewing animals) be kept out of feed given to other ruminants." In January 2005, this was not being fully implemented according to Consumer Reports. See the second link below for full story.
It's time to look more closely at what you are eating. Reduce your risk of disease and help bring back humane practices in our farming.
References:
Eat Wild - Grass Farming and Animal Welfare