Forage Quality Losses in Alfalfa Hay Stacks.

The effects of several months storage for 2 lots of first cutting alfalfa hay were studied to quantify changes in forage quality parameters.  This data from a larger study shows the range in forage quality degradation from 2 lots of first cutting alfalfa hay in large rectangular bales stacked 2 miles apart with moisture levels of 13.5%. Stack A increased in acid detergent fiber (ADF) by 6.2%, neutral detergent fiber (aNDF) by 6.6%, ash by 7.4%, lignin by 1.07%, rumen undegradeable protein (RUP) by 5.15%; and declined in digestible NDF (dNDF) by -3.09%, in vitro dry matter digestibility (IVTDMD) by -11.7%, relative feed value (RFV) by -26 units, and relative forage quality (RFQ) by -52 units in 189 days of storage.  Stack B did not change for most parameters from initial to 192 days of storage, except concentrations increased for ash by 1.56%, fat by 0.09%. Concentration decreased for lignin by -0.16% (P=0.04) and digestible NDF (P=0.11) by -1.39%. Total mass loss is not known but the hypothesis is that microbial growth and metabolism consume carbohydrates and give off carbon dioxide and water leaving the ash and lignin, thus ash concentration increases.  Forage quality declines in storage over several months, even in an arid environment.