Harvest Date and Hybrid Influence on Corn Forage Yield, Quality, and Preservation

Abstract

The selection of corn (Zea mays L.) hybrids and the timing of harvest are important management considerations for dairy and livestock operations. Objectives of this study were to determine the effect of harvest date on yield and quality of corn hybrids and to describe the relationship between harvest date and the yield and quality of corn forage, silage, and stover. During 1998 and 1999, four hybrids were harvested at eight different harvest times between 521 and 1224 growing degree units (GDUs) after planting. Few hybrid or hybrid × harvest date effects were observed. As GDUs accumulated, dry matter yield increased from 8 to 25 Mg ha−1. Lowest concentrations of neutral detergent fiber (NDF) and acid detergent fiber (ADF) and highest concentrations of in vitro true digestibility (IVTD) occurred when forage was harvested between 700 and 650 g kg−1 moisture (1025 and 1186 GDUs after planting). Potential milk yield indices of milk Mg−1 corn forage (794 kg) and milk ha−1 corn forage (19 049 Mg) were reached when corn was harvested between 670 and 630 g kg−1 moisture. In general, silage had 15% lower concentrations of NDF, 8% lower IVTD, 48% lower cell wall digestibility, 7% lower crude protein, and 15% higher concentrations of ADF than unfermented fresh forage. Harvesting can be accomplished until 580 g kg−1 moisture while maintaining 95% of the maximum yield and milk ha−1