Water restriction, thermoregulation, blood constituents and endocrine responses in Sudanese desert sheep

Adult desert rams were used to evaluate the effects of changing the watering regime from free intake (control) to every 24, 48 or 72h. Restricted access reduced the intake of water and food and decreased the morning and afternoon values of rectal temperature and respiration rate. Water restriction increased the packed cell volume of erythrocyte, plasma osmolality, free fatty acids and urea, and decreased glucose concentration. During water restriction, thyroid stimulating hormone level increased in the morning, but decreased in the afternoon; thyroxine level decreased in the morning and afternoon. Cortisol level was depressed by water restriction during the morning and afternoon and showed an overlapping pattern with that of the control during the afternoon. Restriction of water intake by desert sheep results in adjustments in water and heat balance and induces moderate changes in blood metabolites and endocrine responses