The effect of water restriction on certain physiological parameters in Awassi sheep

The effect of water restriction was studied on various physiological parameters in Awassi ewes over a 6-week-period (April–May, 2002). Fifteen dry, multiparous Awassi ewes were randomly assigned to three watering regimes of five ewes per group. Group A received water once every 4 days; Group B once every 2 days and Group C was the control, receiving water daily. Group feed intake and weather data were recorded daily, while rectal temperatures and body weight were recorded weekly. Venous blood was sampled weekly and analyzed for pH, electrolytes, packed cell volume (PCV) and hemoglobin, serum glucose, urea, creatinine, total protein, globulin, albumin, cholesterol, and cortisol. A decrease in body weight was recorded in Groups A and B. In addition, Group A showed significantly (P < 0.05) higher blood urea, creatinine, protein, globulin, and cholesterol concentrations than the control. Blood pH and Na+ were higher and K+ concentrations lower with water restriction than in the control group, while the levels of Cl− and Ca2+ were similar between treatment groups. Similarly, serum cortisol levels did not differ between treatments over the experimental period. The physiological response to water restriction in Group B was not significantly different from that in the control. This study indicates that dry Awassi ewes can withstand a 2 dayswater restriction regime for more than 1month with minimal physiological disturbances, while 4 dayswater restriction induces physiological changes as reflected by changes in most of the serum components assessed, accompanied by weight loss. © 2004 Elsevier B.V. All rights reserved.