The Resistance of a Cow

Radiolab explores the mysterious case of cows refusing to drink water and instead drinking each other's urine—first reported on a Danish farm near a high-voltage power station, then replicated across Denmark and the U.S. The story unfolds as a blend of rural folklore, scientific inquiry, and the hidden tensions between modern agriculture and expanding electrical infrastructure. Journalist Klara Grunel and her team investigate, uncovering a pattern of farmers reporting similar symptoms in their herds, often near power lines or substations. The narrative dives into the concept of 'stray voltage'—electrical leakage into farm environments—and the long-standing debate over whether it harms livestock. While early reports in the 1970s led to lawsuits and state investigations, scientific studies, particularly from Wisconsin, suggest that the threshold for harmful electrical exposure is extremely high, and that most cases are likely due to other factors like poor nutrition or management changes. A pivotal revelation comes from a 2016 Idaho study suggesting that modern, wet, free-stall barns may reduce a cow’s electrical resistance from the long-accepted 500 ohms to as low as 200 ohms—making them far more vulnerable to low-level currents. Yet this data remains unpublished and contested. The episode ultimately reveals that while electricity may play a role in rare cases, the real story is about how farmers, facing economic strain and technological change, may project their distress onto a tangible 'boogeyman'—like stray voltage—when the root causes are often systemic: poor diet, overcrowding, or the emotional toll of losing animals. The episode closes with a poignant reflection on the human cost of industrial farming and the growing demand for electricity in an age of AI and green energy transitions.