Climatização da pós-ordenha e suas interferências nos índices de conforto térmico, variáveis fisiológicas e produtividade de vacas leiteiras

Abstract

Mechanisms to improve the thermal comfort of dairy cow shave been adopted so that the animals can express their full productive potential. In dairy cattle farming, one of the main critical points is the feeding areas. Thus, this work aimed to evaluate the influence of different environments in the post-milking feeding area, on thermal comfort indexes, physiological variables, surface temperatures, production and composition of milk from dairy cows. The experiment was carried out at the Pró-Campo Piracanjuba Farm, in Bela Vista de Goiás-GO. The Latin square design was used, with 4 treatments and 4 experimental periods, with 4 animals per treatment, totaling 16 repetitions. The treatments were different post-milking environments: S: shading; S+V: shading + ventilation; S+V+D: shading +ventilation + shower and AECS - Adiabatic Evaporative Cooling System. The environmental variables were measured: dry bulb temperature, wet bulb temperature, black globe temperature,relative humidity and wind speed, and subsequently the thermal comfort indexes we recalculated: Temperature and Humidity Index (THI), Black Globe Temperature and Humidity Index (BGHI), Thermal Radiation Load (TRL) and Enthalpy (H). The respiratory rate, rectal temperature, surface temperatures, milk production and composition were evaluated. The data were submitted to the analysis of variance and the means compared by the Tukey test, at 5%significance. The AECS environment showed significant improvements (P<0,05) in the environmental variables and thermal comfort indexes, reflecting positively in the productive indexes.