Old world bluestem (OWB) grasses (Bothriochloa spp.) have been used for herbage in the southern Great Plains for over 60 years, but release of new, well-adapted cultivars has led to a dramatic increase in use of these grasses in Oklahoma and adjacent areas during the last 15 years. Little information is available on the chemical composition of OWB grasses. The purpose of this study was to obtain information on the chemical composition of OWB grasses as affected by cultivar and maturation. Forage samples for chemical analyses were obtained from a 2-year field experiment conducted on a Kirkland silt loam soil (Udertic Paleustoll). Ten harvest dates (1-week interval between harvests) and 3 plant parts (whole plant, leaf, and stem) were imposed by split-split plot arrangement on established stands of 'Caucasian', 'Ganada', 'Plains', and 'WW-Spar' bluestem. Responses of variables were neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), and crude protein (CP). Concentrations of NDF, ADF, and ADL increased in whole plant and stem samples during the 10-week sampling periods of both years. Quadratic equations best described changes in ADF during both years and in NDF and ADL in 1983, whereas linear equations best fitted changes in NDF and ADL in 1982. Concentration of NDF in leaves changed very little with maturation, but its change in whole plant and stems paralleled that described for ADF and ADL. Concentrations of CP decreased in all plant parts through harvest date eight (11-week old growth), with the changes best described by quadratic equations. Changes in all constituents were less affected by advancing maturity in leaves than in stems. Maturity had a much greater effect on concentration of all the chemical constituents than did cultivar. Initial concentrations of NDF in all plant parts exceeded the level (ca 600 g kg-1) at which intake would likely be affected. Concentrations of CP also declined to levels by the 5th to 6th harvest dates, particularly in whole plant and stem parts, insufficient to supply daily requirements for most classes of mature beef cattle. The results point to the need to maintain and utilize these grasses to the extent possible in a juvenile, actively growing state to provide nutrition for growing livestock. This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries. The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information. Migrated from OJS platform August 2020
Scholarly peer-reviewed articles published by the Society for Range Management. Access articles on a rolling-window basis from vol. 1, 1948 up to 5 years from the current year. Formerly Journal of Range Management (JRM). More recent content is available by subscription from SRM.