HARVEST MANAGEMENT EFFECTS ON ENSILING CHARACTERISTICS AND SILAGE NUTRITIVE-VALUE OF SEEDED PENNISETUM HEXAPLOID HYBRIDS

Seed propagated interspecific hybrids of pearl millet [Pennisetum glau cum (L.) R.Br.] and elephantgrass (Pennisetum purpureum Schum.) are pr oductive, high in nutritive value, and may have potential as ensiled f orages for dairy cattle, but more information is needed about ensiling management. Two hybrids were evaluated in terms of nutritive value of herbage, herbage characteristics that affect fermentation, and chemic al composition and in vitro organic matter disappearance of silage. Tr eatments included harvesting forage at 6- and 12-wk intervals and ensi ling directly in laboratory silos or ensiling after wilting for 6 h. F orage from all treatments had low buffering capacity (88-176 meq NaOH kg-1 DM) and low but sufficient water-soluble carbohydrate concentrati on (39-72 g kg-1 DM) to allow proper preservation. Unwilted forage had greater water-soluble carbohydrate concentration than wilted, and sil age made from unwilted forage had lower pH, greater lactic acid concen tration, and higher Flieg scores than silage made from wilted forage. Lactic acid was the major end product of fermentation for all silages. Acetic acid concentrations were low and butyric acid was not present. Crude protein, in vitro organic matter disappearance, and neutral det ergent fiber concentrations were affected to a greater degree by plant maturity than by moisture at ensiling. These data indicate that seede d hexaploid Pennisetum hybrids can be successfully ensiled across a ra nge of plant maturities and moisture concentrations. Wilting was not a n advantage when using small laboratory silos, but if hexaploid hybrid cultivars are released, ensiling management should be evaluated furth er using commercial-size silos.