title: In situ dry matter, nitrogen, and fiber degradation of alfalfa, red clover, and eastern gamagrass at four maturities.
abstract: This study compared in situ degradation characteristics of dry matter, N, and neutral detergent fiber (NDF) for alfalfa and red clover with those for eastern gamagrass, a perennial, warm season grass that is native to the Flint Hills of Kansas. Gamagrass had a high proportion of leaf tissue (> 69%) at boot and anthesis stages, at physiological maturity, and after 56 d of regrowth following clipping at boot stage. Gamagrass also had high N concentrations at boot and anthesis stages (2.82 and 2.16%, respectively). Whole-plant gamagrass tissue contained a large proportion of N that was insoluble in neutral detergent (> 51%); however, this was a characteristic only of leaf tissue and was observed on a whole-plant basis because of the large proportion of leaf tissue at all plant maturities. Degradation characteristics of dry matter and NDF generally indicated that stem and cell-wall components from gamagrass at boot and anthesis stages had large maximum extents of degradation. Nitrogen degradation rates (0.047 to 0.059/h) were slower for whole-plant gamagrass than for alfalfa (0.213/h). The most distinguishing characteristic of these findings was not that N from gamagrass degraded more slowly in the rumen than did N from alfalfa or red clover, but that this trait was coupled with N concentrations at harvestable growth stages (boot or anthesis stages) that were similar to legumes.
authors.affiliation: Department of Agronomy, Kansas State University, Manhattan 66506, USA.
authors.forename: W K
authors.initials: WK
authors.lastname: Coblentz
authors.forename: J O
authors.initials: JO
authors.lastname: Fritz
authors.forename: W H
authors.initials: WH
authors.lastname: Fick
authors.forename: R C
authors.initials: RC
authors.lastname: Cochran
authors.forename: J E
authors.initials: JE
authors.lastname: Shirley
mesh_terms: D000821:Animal Feed; D000818:Animals; D002417:Cattle / Q000378:metabolism*; D004043:Dietary Fiber / Q000378:metabolism*; D004063:Digestion; D007700:Kinetics; D008297:Male; D000455:Medicago sativa / Q000254:growth & development / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D006109:Poaceae / Q000254:growth & development / Q000378:metabolism; D012417:Rumen / Q000378:metabolism
chemical_list: D004043:Dietary Fiber; D009584:Nitrogen