Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 8, 1997
Publication Date: N/A
Interpretive Summary: Feeder calves and lambs encounter many stressors during movement from their farm of origin to feedlots. Among these stressors are feed and water deprivation, crowding, a new environment, a new diet, etc. Calves and lambs may call on nutrients stored in their tissues to supply nutrients required for essential metabolic functions. By feeding better diets before ethe stresses of marketing and/or transport, the adverse effects of these stressors can be reduced resulting in improved animal health and performance. This study used sheep deprived of feed as a model to determine the effects of the pre-stress diet nutrient density and salt content on nutrient losses and repletion. Results of this study indicate that increasing the nutrient density of the diet fed before a stress period can improve nutrient status at the end of the stress period but has little or no effect on nutrient status 7 days later. Feeding a low sodium diet before stress may aid in decreasing losses of some minerals (potassium) bu has no apparent effect on losses of water or sodium. Although the effects of feeding higher quality diets to marketing/transport stressed feeder steers and lambs may be short lived, the timing of these improvements in nutrient status may be critical in reducing the adverse effects of marketing and transport stress and, thus, in improving subsequent animal health and performance.
Technical Abstract: Six crossbred lambs were used in a 6 x 6 Latin square design to determine the effects of pre-deprivation diet nutrient density and NaCl content on nutrient losses during a 3-d feed and water deprivation period and subsequent nutrient repletion during a 7-d realimentation period. Main treatments consisted of two pre-deprivation dietary nutrient densities (low w- LOW and moderate - MOD), and three NaCl intakes (0, 2, or 4 g/d) in a 2 x 3 factorial arrangement of treatments. During the pre-deprivation phase, lambs fed the MOD diet had greater (P < .05) K and Zn retention and lower (P < .05) Na retention than lambs fed the LOW diet. Retention of Na increased (linear effect: P < .05), whereas retention of K decreased (linear effect: P < .05) with increasing NaCl intakes. During the deprivation phase, lambs fed the MOD diet had greater (P < .05) water losses but lower Na losses than lambs fed the LOW diet. Losses of Na increased (P < .05) with increasing NaCl intakes, whereas losses of K and Zn decreased (P < .05) with increasing NaCl intakes. Cumulative losses of K, Zn, N, P, Ca, and Fe during the pre-deprivation and deprivation phases were greater (P < .05) in lambs fed the LOW diet than in lambs fed the MOD diet, whereas cumulative losses of Na were greater (P < .05) in lambs fed the MOD diet. Cumulative losses of K increased and cumulative losses of Zn decreased (linear effects; P < .05) as pre-deprivation NaC1 intake increased. Total retentions of N, Na, and Zn over the 14-d sampling period were greater (P < .05) in lambs fed the MOD diet. After 7 d on the realimentation diet, pre-deprivation diet NaCl concentration did not affect nutrient status.