Unraveling the relationship between the topographic distribution patterns of skin temperature and perspiration response in dromedary camels

Abstract

The question of how skin temperature (Tsk), measured at different regions of the skin, can affect sudomotor activity and thus show a pattern in topographic distribution for the perspiration response (PR) rate in dromedary camels was approached and examined in this experiment. Under natural summer conditions, four healthy dromedary bulls, with a mean body mass of 420 kg and age of three years, were measured for Tsk and PR in seven skin regions (i.e. head, neck, shoulder, axillary, hump, flank, and hip) twice daily [between 04:00-05:00 h with a mean ambient temperature (Ta) of 26·78 °C and relative humidity (RH) of 18·25% as well as between 13:00-14:00 h with Ta of 44·78 °C and RH of 5·90%] for two successive days. The experiment has clearly demonstrated some novel findings. In fact, results pointed out that Tsk (P < 0·05) exhibited a distinct topographic pattern that faded almost completely at a higher Ta. Meanwhile, PR unexpectedly manifested a uniform (P ≥ 0·05) distribution throughout the experiment, which appears to serve an eco-teleological purpose in dromedaries. Moreover, the obtained findings indicated that the hump and hip regions in particular can work as thermal windows, yet all seven skin regions can predict whole-skin PR fairly accurately (R2 ≥ 0·90; P < 0·000). Above all, analysis indicated that Tsk in many regions can affect perspiration in camels (R2 < 0·82; P < 0·000), but it failed to demonstrate a topographic pattern in perspiration response at higher or lower Ta; therefore, the data attests that no specific relationship may exist between the topography of a perspiration pattern and the level of regional Tsk. Some shortcomings were noted herein, but research dealing with this subject may very well improve our understanding of the basic functional mechanisms of the thermoregulatory system in this species.