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 bee n plagued by uncontrollable factors such as weather. A system for maki ng 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 squar e 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 betwe en the two remaining conventional bales. Bale types were compared for maximum temperature, 30-d average temperature, degree days > 30-degree s-C, visual mold, dry matter (DM) recovery, total nitrogen (N), acid-d etergent fiber (ADF), neutral-detergent fiber (NDF), and acid-detergen t-insoluble nitrogen (ADIN). Laboratory bales generally remained diffe rent (P < 0.05) from parent conventional bales for most temperature-re lated traits. Agreement between bale types was better for most quality analyses. In an effort to improve relative performance between bale t ypes, 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 conv entional bales. Results showed improved agreement between laboratory b ales of elevated densities and conventional bales for most temperature traits. Acid-detergent-insoluble N levels for laboratory bales were g reatly affected by bale density. High-density laboratory bales had sig nificantly greater ADIN fractions than conventional bales, particularl y in the high moisture treatment. These results implicate bale density as an important factor in damage to alfalfa proteins by the Maillard reaction.