Effect of stage of maturity on composition and nutritive value of sorghum plant components

Abstract

Changes with maturity in chemical composition and nutritive value of whole plant and plant parts of ORO-T and FS-lb hybrid sorghums were quantified. Determinations included: dry matter (DM): crude protein (CP); neutral detergent fiber (NDF); acid detergent fiber (ADF): cellulose; acid detergent lignin (lignin); acid insoluble ash (ash) and in vitro dry matter disappearance (IVDMD). Dry matter yield (DMY) of whole plant and plant portions increased (P<.001) with maturity; DMY of ORO-T head was higher (P<.001) at College Station than at Bushland and DMY of ORO-T head was lower (P<.05) than that of FS-Ib head. CP decreased (P<.001) with maturity in whole plant and leaf. NDF in head decreased (P<.05) with maturity; small nonsignificant changes in NDF were observed in whole and other plant portions. Levels of ADF did not change significantly in whole or plant portions with maturity. Cellulose in whole plant and head decreased (P<.05) and in leaf increased (P<.05) with maturity. Lignin increased (P<.01) in whole plant and stalk; changes in lignin, in leaf and head were not significant. Ash increased (P<.01) with maturity almost linearly in ORO-T and FS-Ib leaf. IVDMD in whole plant decreased (P<.01) with maturity. Mean IVDMD in whole plant decreased (P<.01) and was lower (P<.01) at College Station (55.00%) than at Bushland (61.34%); ORO-T leaf contained higher (P<.05) IVDMD than FS-Ib leaf (59.37 versus 56.97%, respectively); IVDMD of stalk decreased (P<.01) with maturity..