Storage characteristics of large round alfalfa bales: dry hay.
Losses of forage dry matter (DM) and quality in large round bales of alfalfa stored outdoors can be substantial. The objective of this research was to determine the effect of wrap type and storage method on the preservation of dry alfalfa bales stored outdoors. Several methods to wrap large round dry hay bales of alfalfa/grass and grass/alfalfa were investigated, including sisal twine (ST), plastic twine (PT), to-edge net wrap (TEN), cover-edge net wrap (CEN), plastic bale covers (BC) and indoor storage (IS). Some outdoor storage treatments were split between storing either directly on the ground or on a well-drained surface. Storage characteristics were quantified by moisture in the outer layer versus time, final moisture distribution, DM loss, and nutrient retention. Storage length was either 5 or 11 months. Net wrap bales consistently had lower moisture in the outer layer and lower DM loss than twine wrapped bales. Net wrapped bales shed more water than twine wrapped bales, so storing on a well-drained surface was important to reduce damage to the bottom of the bale. Average DM loss across all trials was 19.5%, 11.3%, and 7.3% of DM for ST, PT, and TEN/CEN treatments, respectively. Compared to other treatments, DM losses were significantly less for BC and IS bales. Storing on a well-drained surface reduced DM losses for all treatments. Net wrapped bales tended to have better nutrient retention in the outer layer than twine wrapped bales, but nutrient retention in the bale core was unaffected by wrapping or storage treatment. Wrapping with net wrap increased baling productivity by 32% and reduced losses during wrapping by 65% compared to wrapping with twine. Wrapping bales of alfalfa with a mesh net wrap and storing on a well-drained surface will substantially reduce losses of forage DM and quality compared to wrapping bales with twine.