Abstract
The objective of this study was to evaluate the physiological responses and thermal gradients of goats Saanen and crossbred ¼ Saanen + ¾ Boer created in the semiarid, with the aid of infrared thermography. We used 18 goats, 9 pure Saanen and 9 crossbred distributed in a completely randomized design with factorial 2x2 (two races and two periods), with 18 repetitions. The analysis of variance revealed shift effect (P <0.05) for all variables studied, except for respiratory rate, being observed in the afternoon the highest averages for rectal temperature and surface temperature of the different body regions studied (eyeball, snout, neck, side, rump, flank, thigh, shin and stomach). In the morning, there were the highest averages for the gradients studied. There was no effect of race for any of the parameters evaluated, except for respiratory rate, surface temperature of the eyeball and surface temperature of the snout in the afternoon, being observed for the latter, the highest average for the group of crossbreed. While maintaining the rectal temperature within the normal range for the species, the genetic group Saanen was less tolerant of semi-arid climatic conditions than crossbred ¾ Boer + ¼ Saanen. Even in conditions of confinement, the afternoon in the semiarid becomes stressful for the goats reducing the thermal gradient between the temperatures of the central core and the body surface and this with the environment, increasing respiratory rate.