Heat stress is an underrecognised welfare problem in UK dairy cows, with climate change increasing the frequency and severity of events requiring active cooling management.
Heat-stressed dairy cows show panting, reduced rumination and behavioural changes indicating discomfort. Severe heat stress causes blood alkalosis, reproductive failure and increased susceptibility to mastitis. The welfare burden falls disproportionately on high-yielding Holsteins whose metabolic heat production is higher. Providing shade, mechanical ventilation, water spray cooling and access to cool areas substantially reduces individual welfare impact and is increasingly recognised as essential infrastructure.