Accumulation of digestible materials with growth of forages and digestion of forage dry matter by in vitro incubation with rumen fluid and pepsin

The present study was conducted to suggest an equation to the analysis of f orage dry matter digestion by in vitro incubation with rumen fluid and peps in, and also to suggest an equation, using digestion rate, to the analysis of decreases in dry matter digestibility [DDMD] with growth of forages. For age digestion characteristics were relative digestion rate of dry matter [R DRW], degradation rate of lignin [DRL] and dry matter digestion per unit de gradation of lignin [DWDL]. This method was applied to two tropical forages to evaluate (1) RDRW using DRL and DWDL, and (2) DDMD using RDRW. Accumula tion of digestible materials and DDMD using accumulation rate with forage g rowth (Shimojo Bt al., 1998a, b, c, 1999) were also taken up and applied to the same tropical forages. Two different-type equations for DDMD suggested , roughly speaking, a sort of relationship between digestion characteristic s of forage dry matter in ruminants and accumulation characteristics of dig estible materials in forages.