Heat stress represents one of the key challenges in modern dairy cattle farming. High ambient temperatures combined with high relative humidity adversely affect the health, welfare, and productive performance of dairy cows. His thesis examines the physiological and behavioural responses of cows to heat stress and its consequences, including reduced feed intake, decreased milk yield, changes in milk composition, and an increased risk of ruminal acidosis, laminitis, mastitis, and reproductive disorders. Various measures are available in practice to mitigate the negative effects of heat stress. Technological measures include appropriate barn design and natural ventilation, the use of fans and sprinkler cooling systems, the provision of shade, and the installation of waterbeds. Nutritional strategies include adjusting diets by increasing their energy density and supplementing them with buffers, such as sodium bicarbonate, fats, and vitamins B and E, while also adapting feeding times. Genetic strategies are based on selecting animals with greater heat tolerance and incorporating specific genes, such as the slick gene, into breeding programmes. Continuous monitoring is also essential for timely intervention. This can be achieved by monitoring microclimatic conditions using environmental indicators, such as ambient temperature, relative humidity, and the temperature–humidity index (THI), as well as by monitoring animals’ respiratory rate using wearable sensors, applying infrared thermography, and measuring the body temperature of animals within the herd.
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