Humidification–Cooling System in Semi-Insulated Box-Type Cowsheds Prevent the Loss of Milk Productivity Due to Thermal Stress

Abstract

Heat stress is becoming an increasingly important problem in Lithuanian cowsheds. Microclimate formation systems were evaluated in the seven most popular cowsheds in Lithuania, with different wall and roof constructions, insulation, ventilation intensity controls, and one cowshed was additionally equipped with an air-cooling system—the air is cooled by spraying water droplets with a high pressure. In cowsheds equipped with fans to intensify the movement of air, the temperature does not fall below the outdoor temperature and the temperature humidity index (THI) is higher than outdoors. During the heat period, the THI rises to 82 and the cows get moderate thermal stress, which adversely affects feed intake and milk yield of dairy cows. In the cowshed, where the air humidification–cooling system is installed, the air temperature during heat is lower than the average in the field of 2.61 ± 0.74 °C. Although the relative humidity in the cowshed is on average 16.29 ± 4.12% wetter during heat than outside, the THI in the barn is lower than outside. The air temperature in this cowshed decreases by 3.17 ± 0.86 °C compared to cowsheds without an air humidification–cooling system. The air humidification–cooling system creates good conditions to reduce the conditions for cows to experience thermal stress. Further research is needed to optimize the amount of water spray and droplet size and increase the efficiency of the cooling system.

Statistical Analysis of the Air-Cooling Process in a Cowshed

“…Research was conducted in semi-insulated box-type cowsheds in 244 places in the period from 18 June 2022 to 31 August 2022 in Lithuania. The cowshed is equipped with an Adiabatic Cooling System, which is based on the work of 16 Abbifan 140-XXP-21 fans (tested by Abbi-Aerotech, Hardinxveld-Giessendam, The Netherlands) [1,8]. Each fan is equipped with water nozzles that spray microdroplets (diameters up to 60 µm).…”

“…To establish (find) the influence of temperature and humidity of the air The total number of measurements was 1800 for each sensor. PeakTech P5185 data loggers (manufactured by PeakTech, Ahrensburg, Germany) were used for measurements [1,8]. PeakTech P5185 data loggers provide temperature measurements in the range from −40 • C to 80 • C with an accuracy of 0.1 • C and relative humidity measurements in the range from 5% to 98% with an accuracy of 1%.…”

“…To create a data array, the average values of temperature (T 1 ) and relative humidity (H 1 ) of the outside air, which were obtained from sensors 1 and 5, and the average values of temperature (T 2 ) and relative humidity (H 2 ) inside the cowshed, obtained from sensors 2, 3, and 4, were used. In addition, temperature-humidity index (THI) outside and inside the cowshed was calculated according to the following equation [1,2,8]:…”

“…A necessary condition for keeping cows is to ensure the necessary parameters of the microclimate in the cowshed [1] because increased temperature and humidity can contribute to heat stress in animals [2][3][4]. Heat stress has a negative effect on the physiological state of cows and their productivity [5], and the quality of the obtained milk may deteriorate [6,7].…”

“…It should be noted that the main parameter by which it is possible to determine whether the cows are in conditions of heat stress is the temperature-humidity index (THI). The THI is determined taking into account the values of both temperature and relative humidity of the air [1,3,8]. In particular, the study [9] established a direct relationship between the change in THI for the air outside the cowshed and the THI inside the cowshed; in the cowshed, the THI was significantly higher due to the significant release of heat and moisture from the animals.…”