Storage characteristics and nutritive value changes in bermudagrass hay asaffected by moisture content and density of rectangular bales

Conserving hay at moisture concentrations >200 g kg(-1) is known to cause s pontaneous heating and negative effects on forage nutritive value, While th ese relationships have been evaluated extensively for alfalfa (Medicago sat iva L.), less research has evaluated these factors in warm-season grasses, specifically bermudagrass [Cynodon dactylon (L.) Pers.]. In this study, 'Gr eenfield' bermudagrass was grown on a Pickwick silt loam soil (fine-silty, mixed, semiactive, thermic Typic Paleudult) and packaged in conventional re ctangular bales at five concentrations of moisture (178, 208, 248, 287, and 325 g kg(-1)) and at high and medium bale densities (overall means = 208 a nd 186 kg m(-3), respectively). Bale density had little effect on forage nu tritive value after storage. Furthermore, bale density had no effect (P > 0 .05) on indices of spontaneous heating (heating degree days >35 degrees C, maximum temperature, and 30-d average temperature), visual evaluation of mo ld, and dry matter (DM) recovery. Positive linear relationships occurred be tween concentrations of fibrous forage components and indices of spontaneou s heating; coefficients of determination (r(2)) statistics were similar for each index of spontaneous heating that was used as the independent variabl e in these linear regressions. Concentrations of acid detergent insoluble N and neutral detergent insoluble N expressed on a DM basis were positively related to measures of spontaneous heating in close linear relationships (r (2) greater than or equal to 0.80). Regressions of other N fractions on mea sures of spontaneous heating exhibited lower coefficients of determination, but generally had significant slopes. Results of this study indicate that N in bermudagrass is very susceptible to reductions in bioavailability thro ugh heat damage during bale storage, and that this damage is increased with increases in initial bale moisture.