The influence of high-nitrogen forages on the voluntary feed intake of sheep.

摘要: The objective of this research was to examine the effect high concentrations nonprotein nitrogen (NPN) on voluntary food intake sheep fed high-quality grasses. Wether lambs (n = 6 per treatment) were dried switchgrass (Panicum uirgatum L.; Exp. 1) or tall fescue (Festuca arundinacea Schreb.; 2). In both experiments, urea added forage at 0 (control), 12, 24 g N/kg DM increase NPN concentration. Acid detergent fiber 305 g/kg in although digestibility 663 and 618 g/ kg 1 2, respectively. Voluntary feed control 28.2 19.1 BW respectively, decreased for high-urea treatments 25.2 16.2 (P 0.07) Exp 2 0.03), Total N increased from 29.5 45.7 < 0.01) 28.4 55.9 0.01). Nonprotein 28. 3 53.8% total diets (Exp. 1; P 0.01), 26.4 64.0% 2; Plasma 3.1 6.6 mM 2.9 5.8 as amount increased. These changes resulted an plasma osmolality 298 307 mOsm/kg 0.04), 299 0.06). Increasing through addition caused a significant decrease switchgrass. responses showed no cause-and-effect relationship between intake, concentrations, osmolality.