PERFORMANCE COMPARISONS OF CONVENTIONAL AND LABORATORY-SCALE ALFALFA HAY BALES IN SMALL HAYSTACKS

Field trials designed to study the storage of moist hay have often been plagued by uncontrollable factors such as weather. A system for making laboratory-scale (10.3 by 10.8 by 13.4 cm) hay bales was evaluated in two trials. In the first experiment, three conventional small square bales of alfalfa (Medicago sativa L.) were prepared in the field at each of seven different combinations of moisture and density. One bale was randomly selected to be used as the forage source for laboratory-scale bales of the same density. Laboratory bales were incubated between the two remaining conventional bales. Bale types were compared for maximum temperature, 30-d average temperature, degree days > 30-degrees-C, visual mold, dry matter (DM) recovery, total nitrogen (N), acid-detergent fiber (ADF), neutral-detergent fiber (NDF), and acid-detergent-insoluble nitrogen (ADIN). Laboratory bales generally remained different (P < 0.05) from parent conventional bales for most temperature-related traits. Agreement between bale types was better for most quality analyses. In an effort to improve relative performance between bale types, a second experiment was conducted, in which the laboratory bales were prepared at 1.0, 1.3, 1.6, and 2.0 times the density of the conventional bales. Results showed improved agreement between laboratory bales of elevated densities and conventional bales for most temperature traits. Acid-detergent-insoluble N levels for laboratory bales were greatly affected by bale density. High-density laboratory bales had significantly greater ADIN fractions than conventional bales, particularly in the high moisture treatment. These results implicate bale density as an important factor in damage to alfalfa proteins by the Maillard reaction.