Twenty-four Hampshire X Suffolk wether lambs (40 kg) were used in a 2 X 2 factorial arrangement of treatments to study the influence of water restriction and high levels of dietary K on nutrient utilization. Lambs were offered either a normal K diet (1.86% K) or a high K diet (3.66% K). Additionally, the lambs were offered either a normal quantity of water (previously determined voluntary intake of lambs fed normal K levels) or were restricted to a water intake 80% of normal. Each lamb received 800 g/d of a fescue hay-corn diet (77.5% fescue hay) with an additional 20 g of KCl offered to lambs on high K treatments. The experiment consisted of 14 d of adjustment and 7 d of total collection with blood and ruminal parameters measured on the last day of collection. Both acid detergent fiber digestibility and N balance were reduced (P less than .05) by high K intake. Urinary Mg excretion tended (P greater than .05) to be decreased by water restriction. Plasma Mg concentrations at 2 h post-feeding (PF) tended (P greater than .05) to be reduced by a high K intake at a normal level of water consumption but increased at high K intake when water intake was restricted. A similar pattern was observed for plasma K concentrations. Although high K intake resulted in elevated (P less than .05) ruminal K concentrations both at 2 and 6 h PF, ruminal concentrations of ammonia-N and volatile fatty acids were not affected (P greater than .05) by treatment. These data suggest that nutrient utilization in both the digestive tract and tissues is altered by level of K and modest water restriction.

Twenty-four Hampshire X Suffolk wether lambs (40 kg) were used in 2 X 2 factorial arrangement of treatments to study the influence of water restriction and high levels of dietary Na on nutrient utilization. Lambs were offered either a normal Na diet (.20% Na) or a high Na diet (1.77% Na). Additionally, the lambs were offered either a normal quantity of water (previously determined voluntary intake of lambs fed normal Na levels) or were restricted to a water intake 80% of normal. Each lamb received 800 g/d of a hay-corn diet (77.5% fescue hay) with an additional 38 g of NaCl offered to lambs on high Na treatments. The complete experiment consisted of 14 d of adjustment and 7 d of total collection with blood and ruminal characteristics measured on the last day of the collection period. A high Na intake decreased (P less than .05) the apparent digestibility of neutral detergent fiber, but tended to increase the apparent absorption of Mg. Plasma urea N concentrations were not affected (P greater than .05) by level of Na or water intake. Plasma Na and K concentrations were not affected (P greater than .05) by treatment regimen. A high Na intake increased (P less than .05) plasma Mg concentrations at 6 h post-feeding with a normal level of water intake, but decreased (P less than .05) Mg concentrations at 6 h with restricted water intake. Ruminal ammonia N and K concentrations at 2 h post-feeding were decreased (P less than .05) by a high level of dietary Na. Ruminal Na concentration was not affected (P greater than .05) by treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

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