Study On The Nutrient Of Different Forage Sorghums And The Trend Of Rumen Degradation

The study was carried out at Wuqiao Experiment Station of CAU in 2003 and the labs of CAU in 2004. There were mainly four parts in the study. Firstly, study on the nutrient value of whole stalks, stems and leaves of forage sorghums of different varieties and maturity. Secondly, study on the nutrient value of pre-and post-ensiling of forage sorghums of different varieties and maturity. Thirdly, study on the in vitro gas production experiment of forage sorghums of different varieties and maturity. Fourthly, study on the in vitro gas production experiment of pre-and post-ensiling of forage sorghums of different varieties and maturity. The experiment mainly studied on the nutrient value of whole stalks, leaves and stem of 6 different varieties of forage sorghums, including Jincao No.1, Jincao No.2, Jincao No.3, Jjincao No.4, Jincao No.5 and Jincao No.6, in different maturity (jointing stage, boot stage and ear spouting period), and the change of nutrient value of pre-and post-ensiling and the kinesis of the in vitro gas production. The results showed as follows: Firstly, with the maturity postponed, the components of CP, CA, Ca, P, prussiate decreased significantly and the components of NDF, ADF, WSC and the stem leave ratio increased significantly (p<0.05). And the significant difference was found for the digestibility of DM and NDF, the gas production rate, ferment parameter (a, b and c1) in 48h after fermenting. In the different maturity, the difference wasn't significant in nutrient value, the digestibility of DM and NDF, the gas production rate and ferment parameter (a, b, c1and c2) in 48h after fermenting. Secondly, by contrasting the performance of all varieties of forage sorghums during the ear spouting period, the stem height and hay yield of the second stubble was more than that of the first stubble. But total output of fresh grass of Jincao No.1 was more than that of other breeds. With the maturity postponed, the stem leave ratio increased significantly. Thirdly, by contrasting the nutrient value of all varieties in pre-and post-ensiling, it was found that the content of NDF and ADF of post-ensiling was more than that of pre-ensiling, and the content of soluble sugar was less than that of pre-ensiling (p<0.05). Protein and ash content of the first stubble decreased significantly after ensiling, but that of the second stubble increased significantly. And the significant difference was found for NDFD, the gas production rate and ferment parameter (a, b and c1) in 48h after fermenting, but DMD and c2 was not significant. Fourthly, by contrasting the ferment parameters, it was found that ruminal pH after...