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The Center for Native Grasslands Management




Title: Nutritive value of Eastern Gamagrass conserved as hay or silage
Year: 2002
Author(s): Eun, J. S., Burns, J. C., Gumpertz, M. L., Fellner, V.
Source Title: Proceedings of the Third Eastern Native Grass Symposium
Source Type: Proceedings
pages: 223-228
Original Publication:  
Abstract: Eastern gamagrass, a native warm-season perennial tallgrass, was evaluated for its potential as a forage source in dairy rations. Twenty lactating Holstein cows were fed gamagrass hay or silage without or with supplemental corn to determine effects on milk production. Diets fed in the production trial were also used in continuous cultures to evaluate effects on ruminal fermentation. Diets consisted of gamagrass hay (GH), gamagrass silage (GS), gamagrass silage + low corn (GSLC), gamagrass silage + medium corn (GSMC), and gamagrass silage + high corn (GSHC) with CP levels similar across treatments. Conserving gamagrass as hay or silage did not affect milk yield. Feeding supplemental corn increased milk yield but only at the medium and high levels of corn inclusion (P < 0.05). Milk fat, protein, and lactose contents were similar across all treatments; there was a tendency for milk protein to be higher with GSHC diet (P < 0.07). Gamagrass silage increased the conversion of feed N to milk N compared to gamagrass hay ( P < 0.01). Contrary to expectation, conserving gamagrass as silage lowered milk urea nitrogen compared to hay. Supplemental corn further reduced MUN concentration. Increasing the level of corn supplementation in GS linearly decreased culture pH (P < 0.04) whereas NH3-N was similar across treatments (27.9 mg/100ml). Reduced concentrations of MUN are indicative of improved N status of cows. Difference in N efficiencies for cows fed gamagrass as hay or silage may be related to changes in the protein fraction during the conservation process.
Publisher: The North Carolina Botanical Garden, Chapel Hill, NC, October 1-3, 2002. Omnipress, Madison, WI
Editor(s): J. Randall
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