Creation of comfortable conditions for dairy cow housing ensures maximum realisation of their productive genetic potential; the temperature and the relative (absolute) humidity of the air are of primary importance in this respect. Russian and foreign researchers have established that temperature fluctuations in the range of +10 to +22 ºС and relative air humidity in the range of 50 to 90 % do not have any adverse effect on productivity of animals. According to Russian standards, the minimum inside air temperature should be from + 3 ºC to +10 ºC, with the relative humidity being 40 to 85 % depending on the animal housing technology. Our study showed that in winter in the barn with tied housing of dairy cows, the air temperature varied from +3.5 ºC to +12.3 ºC, with the outside air temperature being from-4.6 ºC to-10.5 ºC. An uneven distribution of air temperature across the barn was registered, with the difference reaching 5 to 7 ºC in some cases. This indicates an uneven and insufficient thermal insulation of the premises. The absolute air humidity in the barn was 5.42 to 9.98 g•m-3 and was also distributed unevenly, depending on the absolute humidity of the outside air, which was 1.46 to 3.28 g•m-3 , and the wind direction, which created additional conditions for active ventilation of the premises. To identify the conditions causing stress in animals, the Thermal Humidity Index was applied; its values were in the range of 45.6 to 57.8, with the recommended values being 65-68. So the housing conditions of cows were considered normal. The study results were used to create Excel graphical and regression models of temperature and humidity conditions and THI in the barn, depending on variation of external weather conditions, with the coefficient of determination R 2 being from 0.915 to 0.969.

Ammonia is significantly lighter than air and has high water solubility. In terms of the health effect, ammonia belongs to choking and neurotropic agents; under certain concentrations it can cause the pulmonary edema and severe damage to the nervous system of the workers and animals. This establishes the need to monitor the ammonia content in the cow barn air, especially in winter, when additional insulating measures are taken in the cow barns due to the negative outdoor temperatures and when the air exchange with the external environment is sharply reduced. The study was conducted in Leningrad Region of Russia in the operating typical cow barn with the dimensions of 21x72 m for 200 lactating cows with the tied housing system and natural ventilation. The study was based on the instrumental express method using experiment designing, computer registration and data processing. The ammonia concentration and other inside climate parameters at certain points of the barn in a given time interval were measured. The ammonia concentration was found to depend on the air temperature and humidity in the barn, as well as on the external weather conditions, which affected these factors. During the observation period, the outside air temperature ranged from-6.0 ºC to-10.6 ºC, with the relative humidity being 72-84 % and the absolute air humidity being 1.6-2.3 kg-3 •m-3. At the measurement points inside the barn, the air temperature ranged from 3.2 to 10.4 ºC, with the relative humidity being 72-90 % and the absolute air humidity being 4.5-7.8 kg-3 •m-3. The ammonia concentration was 2.62-8.92 kg-6 •m-3 , with the maximum allowable value in Russia being 20 kg-6 •m-3. This verified the sufficient air exchange in the barn, providing the necessary conditions for animals. With a decrease in temperature and an increase in humidity in the barn, the ammonia concentration dropped owing to the specific ammonia properties. As the study results, the regression models of ammonia concentration were created with 95 % confidence level, depending on the air temperature in the barn.