# Cooling Effectiveness of the Sustainable Cooling Solution for Cattle: Case Study in Poland
## 1 Introduction  
A significant increase in the average temperature in Europe since the 1990s is observed, making it the fastest-warming continent of the World Meteorological Organizations regions [1]. Moreover, recorded heat waves have become more repeated and severe. Weather heat extremes have profoundly adverse consequences on everyone's day-to-day life and economic activity in many parts of the world, including Poland, the central European country involved in this article. Daily life in livestock farming is affected by excessive heat, and not only during heat waves. A cow becomes heat-stressed when she produces more heat than her body can passively dissipate to the surrounding environment. A temperature range within which adult animals can maintain a normal body temperature and have a comfortable microclimate is called the thermoneutral zone. For cattle it ranges from 16 \({}^{\circ}\)C to 25 \({}^{\circ}\)C and in these conditions the dairy cows can maintain their physiological body temperature of 38.4 \({}^{\circ}\)C-to-39.1 \({}^{\circ}\)C [2]. In the above-mentioned conditions the animal is continually challenged and stressed beyond its physical capacity to cope. In turn, this can cause changes to the immune system, leading to increased disease susceptibility, poor growth, and reduced production [3]. An important consequence of extreme temperatures is also a change in the animal's behavior through prolonged standing time, reduced dry matter intake, as well as increased internal body temperature and respiration rate [3]. Ambient temperature is an important factor affecting heat stress in cattle but environmental humidity is also affecting the severity of heat stress. Therefore, the Temperature Humidity Index (THI) is the most widely used environmental indicator of the effects of heat stress in the livestock sector. This index combines air temperature and humidity, two main parameters that influence cows' well-being, enclosed in one index. The heat stress threshold has been set at daily THI values of 68-72, depending on the formula used according to scientific articles. [PERSON] et al. [4] used [PERSON] et al. 's formula and their studies indicated that adverse effects could occur at a THI level of 68. [PERSON] and [PERSON] [5] used the National Research Council formula and the first losses in milk production were observed when the THI reaches 72 and the highest decrease was observed when the THI is in the range of 76-78. Depending on the THI formula, calculations can be based on the dry bulb temperature, wet bulb temperature, relative or absolute humidity, or the dew point temperature [6]. Selection of the proper formula for the prevailing climate is highly important for results analyses. Cattle breeders striving for efficient and regular production try to protect their herds from high temperatures. Depending on the local climate, this may include the provision of shading, air movement by fans [7], feed-line soakeders, misters [8], and, currently popular, combination systems of misting fans [9; 10]. [PERSON] et al. [11] conducted experiments that clearly show the effect of providing shade and frequent spraying of water on cows' milk yield. However, these solutions did not prevent a positive thermal balance in the animals. [PERSON] et al. [12] have shown that the combined system requires appropriately adjusted regulation that considers the external environment's current conditions to be most effective. The effectiveness of reducing the heat stress of the accessible solution is influenced not only by the efficiency of the system itself but also by the speed and direction of the air, as well as the position of the animal [13]. Commercially available cooling solutions consume large amounts of water and electricity; moreover, the implementation of an appropriate cooling system is essential for proper decision management in dairy farms, improving the animals' thermal comfort and welfare [14]. To solve this problem, researchers are looking for new cow-cooling methods. [PERSON] et al.