Characterization of in situ dry matter and nitrogen digestion of various corn grain forms.
Corn was harvested and stored as either dried shelled, dried ear, high moisture shelled, or high moisture ear. Shelled corns were rolled and ear corns were ground through a forage harvester. High moisture corns were stored in sealed drums. Each corn type was subjected to in situ ruminal digestion with incubation times through 100 h for both original forms and ground at 5 mm. Dry matter, N, and nonprotein DM digestion rates were determined. Unground dried shelled corn possessed the fastest and high moisture ear corn the slowest rate of DM digestion; however, extent of digestion was greatest for high moisture corns within 16 h of ruminal exposure. Grinding increased the rate of shelled corn digestion. Nitrogen digestion rate was fastest for high moisture ear corn and slowest for dried shelled corn. Grinding increased the rate of nitrogen digestion for all corn forms except high moisture shelled corn. Generally, correction for bacterial nitrogen contamination resulted in increased rate of nitrogen digestion. Dried shelled corn possessed the fastest rate of nonprotein DM digestion. Ratio of nitrogen to nonprotein DM rates ranged from .56 to 1.24 for dried shelled corn and high moisture ear corn, respectively. Grinding narrowed this range. Digestion rates of corn forms may not necessarily reflect initial (1 to 16 h) extent of ruminal nutrient availability.
Department of Research and Development, Agway Inc., Syracuse, NY 13221.
J E
JE
Nocek
D000821:Animal Feed; D000818:Animals; D002417:Cattle / Q000378:metabolism*; D004063:Digestion; D005260:Female; D005519:Food Preservation; D009584:Nitrogen / Q000378:metabolism*; D012417:Rumen / Q000378:metabolism*; D003313:Zea mays
D009584:Nitrogen