Forage Quality Changes in Low Moisture Large Rectangular Hay Bales during Storage.

The effects of several months storage in 4 stacks of hay was studied to quantify changes in forage quality parameters.  Crude protein in 1 stack increased 2.1units from initial to final storage, but the 3 other stacks did not change for crude protein. The acid detergent fiber (ADF) increased from 2.7 to 5.3% from initial to final points across all hays.  The change in neutral detergent fiber (aNDF) was inconsistent for the 4 hays.  The RFV index did not change in the alfalfa/grass mix hay, but declined by 14, 21, and 11 units in the other 3 alfalfa hays.  The NDF digestibility in 48 hours (NDFD48, as % of NDF) declined an average of 2.9% across the 4 hays.  The net energy for lactation (NE/Lact), digestible dry matter, relative feed value (RFV), and relative forage quality (RFQ) declined about the same magnitude across the 4 hays.  Lignin, an indigestible fiber fraction, increased an average of 4.3% across the 4 hays.  This paper documents the changes of hay quality in large rectangular hay bales of <10% moisture in several months storage.