IMPROVING THE UTILIZATION OF FIBER AND ENERGY THROUGH THE USE OF CORN GLUTEN FEED AND ALKALI COMPOUNDS

The characterization of corn gluten feed (CGF) as a protein and energy source in ruminant diets was investigated. When fed as protein source to growing steers, CGF had a comparative protein value of 71% of soybean meal as determined by a slope ratio technique. To predict protein degradability, an in vitro protein enzyme assay measured 18% residual nitrogen from CGF compared to 35% (soybean meal), 54% (corn bran) and 86% (corn gluten meal). Corn gluten feed had an extensive (77.4%) and rapid rate (8.1%/h) of neutral detergent fiber (NDF) disappearance in vitro. Corn bran, beet pulp and solka floc NDF extensively disappeared after 96 h of incubation; however, rates of disappearance were all slower than CGF (P \u3c .05). Fattening lambs had a quadratic improvement in feed intake (P \u3c .10), daily gain and feed/gain (P \u3c .05) when CGF was substituted for corn silage. When CGF replaced 25% and 50% of the corn in a high grain ration, lambs had a linear increase in feed intake (P \u3c .05). Four trials were conducted to study the effect of supplementing corn silage diets with alkali compounds on digestability, rumen metabolism and animal performance. Supplementing corn silage diets with buffer mixtures of either sodium bicarbonate (NaHCO(,3)) or ultra-fine limestone (CaCO(,3)) in combination with magnesium oxide (MgO) 2:.75% of dry matter intake) resulted in no signficant increases in dry matter and NDF digestibility when feed intake of steers was restricted. When steers were fed ad libitum, both buffer mixtures resulted in increased dry matter and NDF digestibilities (P \u3c .10). Rumen pH of these steers were increased in both trials with the buffer mixtures. Growing steers fed corn silage diets supplemented with either NaHCO(,3), MgO, NaHCO(,3)+MgO, sodium bentonite (NaBent)+MgO or CaCO(,3)+MgO had no significant improvement in feedlot performance. Lambs ate more feed (P \u3c .10) and had increased rumen pH (P \u3c .01) when fed ad libitum corn silage diets supplemented with 2% NaBent. Combining NaBent and .75% MgO resulted in decreased feed intake and rumen pH compared to NaBent alone (P \u3c .05)