Effect of reconstituting field-dried and early-harvested sorghum grain on the ensiling characteristics of the grain and on growth performance and carcass merit of feedlot heifers

The objective of this study was to determine whether reconstituting field-d ried and early-harvested sorghum grain-affected the fermentation characteri stics and feed value of the ensiled grain when fed to feedlot heifers. In T rial 1, sorghum grain was harvested at 14% moisture, rolled, and reconstitu ted to 25, 30, or 35% moisture, then ensiled in laboratory-scale silos. Lac tic acid concentration increased (d 5 to 90) and pH decreased more rapidly (d 3 to 90) as moisture level increased (P < .05). Acetic acid concentratio n increased (P < .05) with moisture and day postfilling. Concentration of e thanol was highest (P < .05) in the 30 and 35% moisture grains from d 1 to 5, but by d 90 the ethanol concentration in the 25% moisture grain exceeded ( P < .05) that of the two higher-moisture grains. Ammonia N concentration was lowest (P < .05) in the 25% moisture grain at all sampling times postf illing. In Trial 2, 288 heifers (BW = 286 +/- 83 kg) were used to compare t he feeding value of rolled, ensiled sorghum grain harvested at 25% moisture to the same grain reconstituted to 30 or 35% moisture. A steam-naked corn (SFC) diet served as the control. Final live weight; ADG; hot carcass weigh t; backfat depth; marbling score; kidney, pelvic, and heart fat; and liver abscess score were not affected by grain treatment (P > .10). Dry matter in take was highest (P < .10) for heifers fed the 25 or 30% moisture sorghum g rain diets and lowest for those fed the SFC diet; DMI for heifers fed the 3 5% moisture sorghum grain diet was intermediate. Feeding 35% moisture sorgh um grain improved gain efficiency (P < .10)compared with feeding 25 or 30% moisture sorghum grain by 9.0 and 5.7%, respectively. We conclude that reco nstituting sorghum grain beyond the typical moisture levels of 25 to 30% wo uld enhance the fermentation characteristics of the ensiled grain and impro ve gain efficiency in feedlot heifers.