Heat stress in Dairy Cattle Under a Changing Climate : Mitigation Strategies in European Production Systems

Sammanfattning

European dairy cattle production is especially vulnerable to global warming, and different methods for assessing heat stress and implementing mitigation strategies have been explored in previous studies. However, there remains considerable debate regarding the effectiveness of different methods and approaches. This thesis aimed to identify practical indicators for assessing heat stress in dairy cattle, and evaluate management strategies that can improve welfare and thermal comfort within European intensive dairy cattle production. This thesis was conducted as a systematic literature review. The results show that the reliability of heat stress assessment increases when environmental, physiological and behavioural indicators are used in combination, however, accurate assessment often requires continuous monitoring. Mitigation strategies that enhance evaporative and conductive cooling such as water sprinklers, fans, and appropriate bedding materials, were shown to reduce heat load effectively. Additional strategies such as shade provision, management adjustments, and genetic selection can further decrease heat exposure and improve heat tolerance. The effectiveness of these approaches depend on housing design, environmental conditions, and production system characteristics. Consequently, mitigation strategies should be adapted to the specific conditions of each farm, but further research is needed to evaluate the applicability and effectiveness of mitigation strategies in different regions of Europe.