I remembered reading years ago the website of the Union of Concerned Scientists who stated:

“Just like other factories, animal factories are constantly searching for ways to shave their costs. To save money, they’ve redefined what constitutes animal feed, with little consideration of what is best for the animals or for human health. As a result, many of the ingredients used in feed these days are not the kind of food the animals are designed by nature to eat.”

They go on to say:

“The role of drug use in livestock in eliciting antibiotic resistance in disease-causing bacteria like Campylobacter and Salmonella, which originate from farm animals and are transmitted to humans on food, has been well documented. New scientific evidence, however, suggests that resistant food-borne infections may be only one of the health threats from the use of antibiotics in animal operations. Recent studies indicate that antibiotic drug use on the farm may contribute to resistance problems in diseases other than the traditional food-borne illnesses and that bacteria may move from the farm to the community in ways other than on food.”

And:

“The advent of “mad cow” disease (also known as bovine spongiform encephalopathy or BSE) raised international concern about the safety of feeding rendered[1] cattle to cattle. Since the discovery of mad cow disease in the United States, the federal government has taken some action to restrict the parts of cattle that can be fed back to cattle.

However, most animals are still allowed to eat meat from their own species. Pig carcasses can be rendered and fed back to pigs, chicken carcasses can be rendered and fed back to chickens, and turkey carcasses can be rendered and fed back to turkeys. Even cattle can still be fed cow blood and some other cow parts.  Under current law, pigs, chickens, and turkeys that have been fed rendered cattle can be rendered and fed back to cattle—a loophole that may allow mad cow agents to infect healthy cattle.”

Now a report in  The Telegraph may be hinting at something I have been suspecting that the horse DNA found in beef products for example beef burgers could be from horse being fed to cattle.  How world wide could this debacle be?