Jr. Hendrickson et al., LEAF NUTRITIVE-VALUE RELATED TO TILLER DEVELOPMENT IN WARM-SEASON GRASSES, Journal of range management, 50(2), 1997, pp. 116-122
Assessing nutritive value of key grass species in relation to plant de
velopment is essential for producers to efficiently manage livestock e
nterprises, Changes in nutritive value for tiller populations of 2 com
mon Nebraska Sandhills grasses, prairie sandreed [Calamovilfa longifol
ia (Hook.) Scribn.] and sand bluestem [Andropogon gerardii var. paucip
ilus (Nash) Fern.], in response to morphological development was evalu
ated at the Gudmundsen Sandhills Laboratory (GSL) during the 1990 and
1991 growing seasons, Morphological development was determined on a 40
to 60-tiller sample from each block (12 blocks in 1990 and 8 blocks i
n 1991) at ten-day intervals using a comprehensive staging system, In
vitro dry matter digestibility (IVDMD), crude protein (CP), neutral de
tergent fiber (NDF) and lignin were determined for leaves and correlat
ed with the morphological index (Mean Stage by Count), growing degree
days and day of the year, Leaf NDF values of both species remained con
stant while leaf IVDMD declined throughout the summer indicating that
decline in leaf IVDMD was caused by declining cell wall digestibility,
Leaf IVDMD was influenced more by tissue aging than advancing morphol
ogical stage, Leaf CP was significantly different between years but no
t between species indicating leaf CP was largely influenced by environ
mental factors, In both species and for both years, leaf CP initially
declined rapidly to low levels and then stabilized during the vegetati
ve phase, Nutritive value of a single vegetative morphological stage o
ver the growing season was similar to the leaf tissue of the tiller po
pulations, Management decisions by producers depend on accurate assess
ment of changes in nutritive value during the growing season in tiller
populations of these 2 important grasses.