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ARS Home » Research » Publications at this Location » Publication #80666
Title: EVALUATION OF EASTERN GAMAGRASS GRAIN AND COTTONSEED MEAL AS PROTEIN SUPPLEMENTS FOR SHEEP FED MATURE EASTERN GAMAGRASS HAY

Author
item BAILEY, DEREK - MONTANA STATE UNIV.
item Sims, Phillip

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/19/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Eastern gamagrass is a highly palatable, perennial warm-season grass that is adapted throughout the southern and central plains and much of the eastern United States. This grass has the potential to produce grain with nearly 30 percent crude protein and 90 percent digestibility. We compared eastern gamagrass grain to cottonseed meal as a protein supplement for yearling lambs consuming mature eastern gamagrass hay. Neither supplement affected hay intake or hay digestibility. Both supplements increased ration digestibility. Lambs receiving eastern gamagrass grain excreted less nitrogen in their urine and retained more nitrogen than lambs supplemented with cottonseed meal. Eastern gamagrass grain was comparable, and perhaps somewhat superior, to cottonseed meal as a protein supplement for moderate to low quality forage.

Technical Abstract: Eastern gamagrass is a highly palatable warm season grass that has potential as a perennial grain crop with a protein content near 29% CP. Twelve wether lambs were used to evaluate eastern gamagrass grain and cottonseed meal as protein supplements for mature eastern gamagrass hay in a conventional digestion and nitrogen balance trial. Voluntary intake, organic matter (OM) intake, neutral detergent fiber (NDF) digestibility, and nitrogen balance were determined for hay alone (CONTROL), hay plus eastern gamagrass grain (GGG), and hay plus cottonseed meal (CSM) treatments. Organic matter intake of supplemented lambs was higher (P<.001) than lambs fed only hay. There was no difference (P=.22) in OM intake between GGG and CSM supplement treatments. Total tract digestibility of OM differed (P<.001) among the GGG (61.8%), CSM (58.6%), and CONTROL (54.9%) treatments. Differences in digestibility may be the result of addition of highly digestible protein supplements, rather than a increase in digestibility of the hay. Adding the supplements improved (P<.001) the digestible (DE) and metabolizable energy (ME) of the hay ration. The diet with GGG had higher (P<.001) DE and ME values than the CSM supplemented ration. Nitrogen retention was greater (P<.001) for supplemented lambs (+5.7 g N/d) than for unsupplemented lambs (+1.7 g N/d). Lambs supplemented with GGG retained more (P=.01) nitrogen than lambs supplemented with CSM even though nitrogen intake was similar (P=.98) among treatments. The difference in nitrogen retention between the supplements was the result of nitrogen excreted in the urine. Urine nitrogen from the CSM treatment was higher (P=.01) than the GGG treatment, while fecal nitrogen values for both supplement treatments were similar (P=.63).