The objective of this research was to evaluate different times of exposure of animals to cooling in the waiting pen on the comfort index, physiological parameters and milk production of girolando 7/8 cows. As treatments, four times of exposure of animals to adiabatic evaporative cooling system (AECS), 0, 10, 20 and 30 min were considered. The experiment was conducted during the summer season and lasted 56 days. Sixteen cows were used with an average daily milk production of 18 kg, distributed in 4 x 4 Latin square design. The dry bulb temperature (DBT) and relative humidity (RH) were recorded every minute, which allowed to determine the efficiency of the AECS through the Temperature and Humidity Index (THI) and enthalpy (h). The respiratory rate (RR), rectal temperature (RT) and temperature of the coat (TC) were measured before and after cooling. The 30 min treatment kept the environmental variables and the comfort indexes within recommended limits. The physiological variables (RR, RT and TC) were lower in the 30 min treatment and reflected positively on milk production, which increased 4.4% compared to the 0 min treatment.
ambience; animal biometeorology; dairy cattle
