The study was carried out at Maryout Research Station, 35 km to Southwest of Alexandria that belongs to the Desert Research Center (DRC), Egypt. The study was performed to evaluate the thermoregulatory ability of one-humped she camel (Camelus dromedarius) during summer and winter seasons. Five adult healthy shecamels aged 6-8 years with initial body weight recorded 522.00±3.52 and 613.00±6.63 kg for summer and winter seasons, respectively, were used. The animals were kept in outdoor pen (un-shaded). Rectal (RT), skin surface (SST), surface coat (SCT) and mid-coat (MCT) temperatures were measured 3 times daily (6:00 am; 12:00 pm and 6:00 pm) during the ten middle days of each month during both summer (from June till August) and winter (from December till February). Ambient temperature and relative humidity were recorded at 06:00, 12:00 and 18:00 hr during summer and winter seasons. Regarding the effect of season on RT, the results indicated that there were significant differences (P<0.01) between seasons. Average RT was 38.6 and 37.45 ºC during summer and winter seasons, respectively. In general, seasonal and diurnal variations in rectal temperature followed closely observed changes in the temperature-humidity index (THI). Skin surface temperature (SST) varied between the selected sites over the animal's body and between seasons. The changes in SST at the selected sites were higher (P<0.01) under cold climatic conditions (winter) than warm climatic conditions (summer). These results indicated that SST was dependent on climatic conditions. The results revealed that SST recorded highly (P<0.01) significant differences between hump (represent site exposed to sun) and abdomen (represent site not exposed to sun). The hump site was the warmest during summer (35.5 and 33.27 ºC) and winter (16.23 and 20.17 ºC) for SCT and MCT, respectively, whereas AB site recorded the lowest readings during summer (30.30 and 28.57 ºC) and winter (10.70 and 13.07 ºC) for SCT and MCT, respectively. The mid-coat temperature is less than surface-coat temperature in summer in order to decrease the transfer of heat from air to the skin. Meanwhile, the mid-coat temperature is more than surface-coat temperature in winter to minimize or prevent the dissipation of heat from the skin to the environment and preserve skin temperature as much as possible. The camels' coats, which are hairy rather than wooly in nature, create a favorable microclimatic buffer zone that separate the body surface from the surrounding harsh climatic conditions.

Skin temperature is essentially a resultant of heat production and heat loss, and as these two factors may be altered by wide ranges in environmental conditions, the present study was conducted to compare the influence of hot (summer) and cold (winter) environmental temperatures on the diurnal variations of surface skin temperature (SST), skin thickness (ST), skin hydration (SH%), skin electrical conductivity and live body weight (LBW) changes of the dromedary camels during both seasons. The study was carried out at Maryout Research Station, 35km Southwest Alexandria, which belongs to Desert Research Center (DRC), Egypt. Five adult healthy she-camels (Camelus dromedarius), 6-8 years old, with initial body weight of 522.0±3.52 and 613.0±6.63 kg for summer and winter seasons, respectively, were used. The animals were kept in unshaded outdoor pen. Surface skin temperature (SST), skin thickness (ST) and skin hydration (SH%) were measured at seven regions including Neck (NE), Shoulder (SH), Hump (HU), Hip (HI), Fore-limb (FL), Hind-limb (HL) and Abdomen (AB) on both right and left sides of the animal's body. Measurements were taken three times daily (06:00, 12:00 and 18:00 hr) during the middle ten days of each month in both summer (from June till August) and winter (from December till February) seasons. The daily diurnal ambient temperature, relative humidity and solar radiation were also measured at 06:00, 12:00 and 18:00 hr. The results indicated that SST differed significantly (P<0.01) between hump (the site more exposed to sun) and abdomen (less exposed to sun). The differences between the two values were 5.13 and 6.44ºC during summer and winter seasons, respectively. The differences between SST at the selected sites were the highest (P<0.01) under cold climatic conditions (winter) than warm climatic conditions (summer). As expected, measured SST at midday (12:00 hr) was consistently higher than measured SST at morning (06:00 hr) and evening (18:00 hr), but was significantly higher during summer than winter. As for skin thickness, the NE, SH, HU and HI sites were significantly (P<0.01) thicker and higher of its water content than the other sites during both summer and winter seasons. Values of ST and SH% were higher during winter compared with summer values. This rise may be attributed to the increase in fat stored in subcutaneous layers and to the increase in body fluids. The values of the electrical conductivity of the skin were higher in winter months than in summer months. The neck region had the highest values while the fore limb had the lowest values in both summer and winter. There was a positive correlation between the electrical conductivities of the different skin regions and the water content of the same region in summer and winter.