Heat stress affects billions of cattle annually as temperatures rise, causing reduced productivity, immune suppression, and significant suffering that is increasingly difficult to manage as climate warms.
Heat stress in cattle is physiologically similar to fever — elevated core temperature causes biochemical disruption, suppressed immune function, reduced organ performance, and behavioral distress. Cattle seeking shade, refusing to lie down, bunching near water sources, and panting heavily are showing signs of genuine suffering. The welfare impact scales with duration — transient heat stress is manageable, but chronic summer-long hyperthermia in feedlots or poorly ventilated dairies causes cumulative harm. Climate change makes this a growing rather than stable welfare challenge.