This work was carried out to evaluate the physiological thermoregulation responses of Girolando-breed dairy cows kept in feedlot during summertime. A total of 15 animals were used, belonging to three genetic groups: 1/2, 5/8 and 3/4 Holstein-Gir (HG), with five cows from each genetic group, distributed in a completely randomized design, in subplots. The physiological parameters were sweat rate (SR), respiratory rate (RR), epidermis temperature (ET) and coat surface temperature (CST), and were evaluated once a week, during nine weeks, from December 2009 to February 2010, totaling 135 observations. Throughout the experimental period, climatic data were recorded using an automated weather station, and later used to calculate the different thermal comfort... |