This work aimed to evaluate the performance, rectal temperature and respiratory ratio of dairy heifers, from three genetic groups Holstein × Zebu (7/8HZ, 15/16HZ, Graded Holstein-GH), confined and fed total mixed diet with different levels of neutral detergent fiber (30 and 60%), using chopped elephantgrass (Pennisetum purpureum, Schum., cv. Mineirão) as forage. Intake, weight gain and physiological responses of these animals were determined under different environmental conditions. The experiment was conducted according to a 3 × 2 factorial arrangement (genetic […]