Resilience of Lambs to Limited Water Availability without Compromising Their Production Performance

SIMPLE SUMMARY: Feeding a pelleted diet under the prevailing water scarcity in arid regions, coupled with the low moisture content of that diet, raises the question about the precise level of water restriction that lambs can tolerate without compromising their production performance. Therefore, this study aimed to evaluate the production performance of lambs subjected to different levels of water restriction, which in the long run could help in the rationalization of the water consumption of the livestock production sector in arid and semi-arid regions. Lambs subjected to drinking-water restriction demonstrated efficient water use and conservation by drastically reducing water loss in feces and urine. Although dry-matter intake was decreased as a result of restricting water intake, the animals still gained reasonable body weight. It is surprising that the efficiency of nitrogen utilization was improved with the increasing level of water-intake restriction. The findings of the study revealed that lambs could tolerate up to 33% of water-intake restriction, depending on the climatic conditions and the type of diet. ABSTRACT: Water scarcity is a common phenomenon in arid and semi-arid regions, which could have tremendous effects on livestock production. This study aimed to determine the level of water restriction that lambs fed on a pelleted diet can tolerate without compromising their production performance. A total of 24 male Najdi lambs were housed individually and randomly allocated into three equal groups, namely ad libitum water intake, 33% water-intake restriction, and 67% water-intake restriction. Dry-matter intake, feed conversion ratio, and average daily gain were decreased (p < 0.05) with the increasing level of water restriction. Water restriction had also reduced (p < 0.05) nutrient digestibility. The water-conserving ability of the water-restricted lambs was manifested by the production of concentrated and lower (p < 0.05) quantities of urine and feces. Meanwhile, serum osmolality and concentrations of albumin, total protein, urea-N, glucose, and non-esterified fatty acids were increased (p < 0.05) with the increasing levels of water restriction. It is surprising that lambs subjected to 67% water restriction retained more (p < 0.05) nitrogen relative to intake and had better (p < 0.05) efficiency of nitrogen utilization. It was strongly evident that lambs could tolerate water-intake restriction of up to 33% without compromising their production performance.