Spatial Variability of Microclimatic Parameters in a Closed Compost-Bedded Pack Barn for Dairy Cows with Tunnel Ventilation

The aim of this study was to evaluate the spatial distribution of microclimatic conditions inside a closed Compost-Bedded Pack Barn (CBP), equipped with a negative ventilation system in tunnel mode, associated with an evaporative cooling system (EC), through geostatistical analysis. The research was conducted during the summer in a CBP placed in the area of Zona da Mata, Minas Gerais, Brazil. In different periods of the day, microclimatic parameters were measured inside the building, such as air temperature and relative humidity. Temperature and Humidity Index was subsequently calculated. The results showed the predominance of strong spatial dependence, as well as variability of attributes within the CBP, with heat stress zones occurring. It was verified that the most critical conditions were mainly found from the central part of the CBP towards the northwest face, close to the exhaust fans. On summer afternoons, the entire area of the CBP was in a situation of discomfort. As a result, it is possible to affirm that an increase in the ventilation flow inside the building could allow to reach more favourable conditions for the thermal comfort of the animals. It was observed that the EC can help to improve the internal thermal conditions of the barn. However, probably due to the lack of thermal insulation of the enclosures, it does not allow to reach a spatial thermal uniformity and to create comfortable conditions for dairy cows.