THE PROBLEMS OF MICROCLIMATE IN LITHUANIAN COWSHEDS
The experimental studies were carried out in the most common cowsheds in Lithuania. The cowsheds involved in the research featured different insulation patterns and livestock keeping technologies where cows were kept tied or loose. The efficiency of ventilation system was measured in 7 cowsheds based on the variation in air temperature, air relative humidity (RH) and ammonia. The main problems of microclimate in Lithuanian cowsheds were found to be as follows: a high relative humidity resulting in water vapour condensation on the roof structures; the air temperature is regularly below the recommended minimum of -7 °C; the air temperature is regularly above the recommended maximum of 25 °C. Optimization of the microclimate in cowsheds concerned, it is recommended to adjust the ventilation intensity based on the difference of air temperatures within the barn and outdoors. During cold months of winter it is recommended to keep the air temperature in semi-insulated cowsheds by 8–11 °C higher than that outdoors, whereas in uninsulated box-type cowsheds with roof cement – higher by 5–7 °C, and in uninsulated box-type cowsheds with roof metal – higher by only 3–5 °C. During severely freezing periods of outdoor temperature, the air temperature was found not to drop below -7 °C only in insulated cowsheds. Whereas during extremely hot days when the outdoor temperature rises above 26–28 °C, the cowsheds of all types (those insulated and uninsulated) were found to be too hot for cows. Consequently, thermal insulation of a cowshed’s roof and adjustment of the ventilation intensity are not sufficient for solving the problems caused by heat stress in the cowsheds.