EFFICIENCY OF INSTALLED COOLING SYSTEMS IN DAIRY BARNS DURING HOT SEASON

Abstract

Hot season of the year has profound effects on the production, health, profitability, and welfare of dairy cows. The objective of this study was to evaluate the efficacy of cooling systems in controlling the microclimate condition inside the two dairy barns. There was set out to compare the ambient conditions inside the barn with environmental weather data obtained from local meteorological station. The experiment was carried out at the height of summer (from 15th of June to 31st of August) in two familiar dairy farms. Within the barns air temperature, relative humidity and their ratio expressed as temperature humidity index (THI) were measured hourly during the trial period using data loggers. The Pearson’s coefficient of correlation demonstrates that climate condition inside the barns and the official local meteorological station significantly correlate. The air temperature and THI were significantly higher in the Farm 1 (1.53±0.2390C higher, t=6.420; p<0.001, and 2.05±0.344 units higher, t=5.973; p<0.001, respectively) and in the Farm 2 (1.65±0.2520C higher, t=6.549; p<0.001, and 2.12±0.357 units higher, t=5.927; p<0.001, respectively) compare with the environmental weather data. The method of GLM, multivariate procedure, showed that there was statistical significant differences in the minimal values for daily microclimate parameters inside the barns before and after installation of cooling equipment. However, the interaction between the farm and cooling system, months and days of hot summer season showed statistical significant influence on the microclimate conditions inside the cow barns with exception for the maximal values for air temperature and THI. In conclusion, due to farm specific and unpredictable variability in climate conditions inside the cow barns and their correlation with environmental weather data, the installed cooling systems could provide better climate zone in the barns for increased milk production but couldn’t completely satisfy capacity of cooling during the day time with highest air temperature.