Twenty-five years after I revealed the practices of the industrial food giants, the profits – and dangers – of mass producing meat and milk have only grown

Cats have long been kept at American dairy farms to kill rats, mice and other rodents. In March 2024, a number of barn cats at dairies in the Texas panhandle started to behave strangely. It was like the opening scene of a horror movie. The cats began to walk in circles obsessively. They became listless and depressed, lost their balance, staggered, had seizures, suffered paralysis and died within a few days of becoming ill. At one dairy in north Texas, two dozen cats developed these odd symptoms; more than half were soon dead. Their bodies showed no unusual signs of injury or disease.

Dr Barb Petersen, a veterinarian in Amarillo, heard stories about the sick cats. “I went to one of my dairies last week, and all their cats were missing,” a colleague told her. “I couldn’t figure it out – the cats usually come to my vet truck.” For about a month, Petersen had been investigating a mysterious illness among dairy cattle in Texas. Cows were developing a fever, producing less milk, losing weight. The milk they did produce was thick and yellow. The illness was rarely fatal but could last for weeks, and the decline in milk production was hurting local dairy farmers. Petersen sent fluid samples from sick cows to a diagnostic lab at Iowa State University, yet all the tests came back negative for diseases known to infect cattle. She wondered if there might be a connection between the unexplained illnesses of the cats and the cows. She sent the bodies of two dead barn cats to the lab at Iowa State, where their brains were dissected.