The impact of ventilation type on the heat load of dairy cows
Slovak University of Agriculture in Nitra, Faculty of Engineering, Department of Building Equipment and Technology Safety, Trieda Andreja Hlinku 2, CZ949 76 Nitra, Slovak Republic
Heat load in cattle causes deterioration of health and reduced production of milk. Therefore, it is necessary to protect cows by appropriate passive and active means and monitor the air quality in barns. Based on several indicators of environmental quality, is possible to make a more comprehensive assessment of the microclimate and more precise conclusions. This study, was monitoring the values of air temperature, relative humidity, and air velocity in two barns with the same volume and layout with floor dimensions of 26.6 m × 62.1 m. In barn 1, roof ridge of which had underwent only partial reconstruction, there were installed fourteen basket fans with a total fan performance Q(1)fans = 218,400 m3 h-1. In barn 2, there were twelve panel fans with a total fan performance Q(2)fans = 289,320 m3 h-1. The resulting THI, HLI and ETIC values were compared in relation to each other and in relation to the recommended values.
Despite the operating ventilation technology and enlargement of wall openings, the above-limit values of climatic characteristics were observed in both barns during tropical days. There were no differences between the barns (p ˃ 0.05), in barn 1: THI(1) = 83.10 ± 0.51; HLI(1) = 85.62 ± 1.42; ETIC(1) = 27.24 ± 0.31, and in barn 2: THI(2) = 83.12 ± 0.34; HLI(2) = 85.77 ± 1.50; ETIC(2) = 27.29 ± 0.28, however, there were found significant differences in values of temperature indices obtained in the detailed measurements at points arranged perpendicularly, as well as parallelly, to the direction of air velocity in the animal zone (p < 0.05).