1a.Objectives (from AD-416):
Determine how fructan profiles in orchardgrass and bermudagrass forages are affected by the time of year in which they are grazed (early vs. late in the growing season), as well as by time of day.
1b.Approach (from AD-416):
Orchardgrass and bermudagrass samples, collected in Virginia during the spring and late summer (mid-April to late August) will be analyzed for fructan content. Fructans will be extracted from the samples with boiling water and analyzed by anion-exchange high-performance liquid chromatography (HPLC) coupled to pulsed amperometric detection (PAD). Profiles will be compared to those of a sample harvested at the optimal growth stage to determine how seasonal and diurnal variations affect the relative changes in amounts and types of fructans in the forages.
Forage-Animal Production Research Unit's chromatographic method for carbohydrate analysis was made more reproducible. Orchardgrass fructan content tended to be highest in mid-April and to decrease from late April to mid-June. The maximum chain length of fructans was highest in the early spring. Total sugar content was generally higher in the afternoon, although fructan content seldom varied. Analyses of bermudagrass confirmed an absence of fructans, which was expected for a warm-season grass but difficult to confirm with some of the standard analytical procedures. The amounts of other sugars in bermudagrass were generally similar in the morning and afternoon.