CASE STUDY: Effect of grazing, stage of maturity at harvest, and glycerol treatment on wheat harvested as silage

The objective of this project was to examine the effect of grazing restriction, stage of maturity at harvest, and addition of glycerol to wheat (Triticum aestivum L.) harvested as silage. The project design was a split-split plot, and the first treatment level was nongrazed wheat compared with wheat grazed just before first hollow stem. The secondary treatment structure was harvesting the wheat at anthesis versus soft dough maturity. The third treatment structure was applying glycerol to the wheat at 0, 5, 10, or 15% of DM before ensiling. Nongrazed wheat produced more yield than did grazed wheat (P = 0.04), and harvesting at soft dough produced more yield than did harvesting at anthesis (P < 0.001). The change in NDF, ADF, and IVDMD was greater for nongrazed wheat from anthesis to soft dough maturity compared with grazed wheat (P ≤ 0.06). Grazing had no effect on postensiling forage chemical composition. Silage pH reached acceptable levels (4.0 to 4.2) but was not affected by plant maturity. Glycerol addition, however, appeared to result in a slight improvement of IVDMD (P = 0.04).