Concentrated Animal Feeding Operations, or CAFOs, often pack animals together in inhumane, unsanitary conditions. (Photo: Peter Menzel.)

Modern cattle spend many months in CAFOs, eating grains that fatten them quickly before slaughter. The corn and silage diet creates a fattier meat and a cow that’s ready for slaughter sooner, but it also sicken the animals. Cattle are ruminants; they’ve evolved to digest grass. To keep CAFO cows from falling ill or dying, managers inject grain-fed cattle with antibiotics. This helps them survive their unnatural diet and the germs like E. coli that thrive in these confinement facilities.

But this antibiotic stop-gap has widespread ramifications. Antibiotic residues remain in industrial beef, which may lead to the rise of superbugs and antibiotic resistance in humans. The rise of MRSA has been associated with CAFO production, writes editor Imhoff. Even as these connections are studied, the agriculture world continues to use more antibiotics by far than the medical establishment. “The states of Iowa and North Carolina, for instance, each administer more antibiotics for animal production than the entire human population of the United States uses for medical purposes,” Imhoff writes.