Heat management must be treated as a carcass-quality control point

Heat stress does not begin only when the thermometer reaches extreme temperatures. Scotland’s Farm Advisory Service stresses that the combination of temperature and humidity should be assessed through the temperature-humidity index, or THI. In cattle, stress is considered to begin at a THI of 68; at summer humidity around 60%, that threshold can be reached at roughly 22°C. The guidance links welfare, performance and quality. Even moderate heat stress can reduce feed intake, daily gain and fertility, while also affecting overall meat quality. As a reference, it cites SRUC work indicating that one additional heatwave day per 100 days is associated with around three more days of age at slaughter. This is not a forecast for every farm, but it signals that weather affects production and carcass outcomes. In practical terms, water is the first bottleneck. The guidance gives an upper reference of 15 litres per day for every 100 kg of liveweight, with requirements rising by at least 10–20% in hot weather. Flow rate, trough capacity and access matter as much as nominal water volume. Shade, calm early-morning handling and avoiding work during the hottest hours reduce additional heat load. Feeding time should also be part of the plan. Feeding in late afternoon shifts the peak of rumen-fermentation heat—normally four to six hours after feeding—towards the cooler night period. The conclusion for producers and buyers is clear: heat management is not merely an emergency measure. It is preventive quality work that protects animals and reduces variation in growth, carcass performance and commercial quality.