Physiological responses of Saudi Arabia indigenous goats to water deprivation

This study was conducted to evaluate and compare the physiological responses to water deprivation and rehydration in three local goat breeds (Hipsi, Aardi and Zumri) of Saudi Arabia under hot summer conditions. Six 10-12 months old bucks from each breed with a range in body weight of 30-42 kg were used. Three days of water deprivation resulted in an average reduction of 20.6% in body weigh. Furthermore, feed intake was also decreased immediately following water deprivation from day 1 and continued to decrease until the last day of water deprivation in which feed intake decreased from 123.7 +/- 2.7 to 17.0 +/- 1.4 g/kg W-0.75 for the three breeds. Water deprivation had no clear effect on the respiratory activity of Aardi and Zumri goats, while being reduced in the Hipsi breed by 30%. There was an increase in the pm values for rectal temperature (39.3 +/- 0.1 to 39.7 +/- 0.1 degrees C) following water deprivation in all breeds. Packed cell volume, plasma osmolality and plasma levels of Na increased by 38, 17.8 and 13.6%, respectively, by the end of the dehydration period. There was a significant increase (P < 0.01) in plasma urea from 34.3 +/- 1.2 to 85.5 +/- 4.8 mg/dl, and plasma creatinine from 0.9 +/- 0.1 to 1.7 +/- 0.1 mg/dl following water deprivation in all breeds. During the first 15 min of rehydration, goats consumed an average of 6.81 water that amounted to approximately 23.5% of their dehydrated body weights, and goats were able to regain most of their body weight losses. There was a slow recovery in plasma osmolality and packed cell volume, indicating a slow absorption of water from the gut to the vascular system. It could be concluded that these three local goat breeds showed a great tolerance to water deprivation during hot summer conditions of Saudi Arabia. There were no apparent differences between breeds in their ability to withstand water deprivation, restoration of body weight loss or physiological parameters. (c) 2005 Elsevier B.V. All rights reserved.