Abstract
To determine the nutritive value of whole-plant silage and stover, we ensiled and compared 4 sorgo types (S), 2 dual purpose type (DP), 6 grain types (G), 1 sorghum-sudangrass hybrid type (SS) and 2 hybrid maize (M) at the adequate harvesting stages. The digestion trials in vivo were carried out with 4 goats. Neutral and acid detergent fiber contents in whole plant of S, DP and M decreased in that order, differences being over 10%, respectively. Silages of S tended to have low dry matter concentration (DM), high pH, low amounts of lactic acid and total volatile fatty acids and high volatile basic nitrogen concentration (VBN) in total nitrogen. The digestibilities of dry matter, organic matter and nitrogen free extract and the contents of digestible organic matter and TDN in whole plant of S, DP and M increased in that order, with differences over 10%, respectively, except for "Sugar Graze" which had a higher digestibility among sorgo type sorghum. Digestible dry matter concentration (DDM) of stover silage was lowest in DP hybrid "Suzuho" ensiled at dough stage, and was highest in hybrid maize at yellow ripe stage, and their difference was about 18%. The DDM of G inbred line "F_6-3 A-5", which had brownmidrib-18 (bmr-18) and bloomless (bm) genes, ensiled at dough stage was 61.8% as much as that of hybrid maize. It is considered that the TDN concentration for the dual purpose sorghum can be obtained by improving the digestibility of stover. For the sorgo type and sorghum-sudangrass hybrid type, it should be expected to improve ensiling characteristics as well as digestibility.
