Housing ventilation is one of the most underappreciated determinants of cattle welfare. Inadequate ventilation causes ammonia accumulation, respiratory disease, and heat stress that affect thousands of cattle silently each year in UK dairy and beef units.
Cattle in poorly ventilated sheds breathe ammonia-contaminated air that irritates mucous membranes, predisposes to respiratory infection, and causes eye discharge. In hot weather, inadequate ventilation causes heat stress that impairs immune function, reduces feed intake, and causes reproductive failure in dairy cows. Calves in stuffy calf housing have dramatically higher BRD rates than calves in well-ventilated pens. Welfare monitoring should include regular ammonia detection, observation of respiratory rates, and assessment of lying and standing patterns that indicate thermal comfort. Building design that prioritises ventilation from the outset is more cost-effective than retrofitting.