Figure 4.

Differences between the surface temperatures of the peripheral and central regions in newborn animals. The differences in the surface temperature found between the central region (periocular, El1) and the peripheral region (thoracic or pelvic limb, El2) in both water buffaloes (A) and newborn piglets (B) are shown. In the case of the newborn water buffalo, an average difference in the temperature between both regions was set at 4.1 °C. In the piglet, an average difference in the maximum temperature of both regions was set at 9.4 °C. The possible explanation for this fact is that, during the perception of cold, the sympathetic postganglionic fibers release adrenaline and norepinephrine, which act on the α-2 adrenergic receptors present in the endothelium. This causes the vasoconstriction of the peripheral blood vessels that reduce the level of heat loss, preserving the temperature in central areas such as the head and thorax. The maximum temperature is indicated with a red triangle, and the minimum temperature is indicated with a blue triangle. Radiometric images were obtained using a T1020 FLIR thermal camera. Image resolution: 1024 × 768; up to 3.1 MP with UltraMax. FLIR Systems, Inc. Wilsonville, OR, USA.