Evaluation of changes in forage chemical composition of some range grasses and their correlation with digestibility (Case study: The sand dunes of Bostan, Khouzestan)

Knowledge of digestibility of different plant species and relationship between digestibility and chemical composition of forage is one of the basic requirements in order to qualitative and quantitative management of livestock nutrition in rangelands. This research was aimed to evaluate the changes in chemical composition of forage during the growth stage and relationship between forage digestibility and forage chemical composition in most important tropical range grasses including Cenchrus ciliaris, Panicum antidotale, Pennisetum divisum and Cymbopogon olivieri. Sampling was replicated every two weeks. Forage quality parameters including CP, WSC, CF, ADF, Ash, and DMD were measure using NIR technique. Results showed that forage quality differed significantly in the studied species and growth stages. According to the obtained results the highest and lowest forage quality was obtained for Cenchrus ciliaris and Pennisetum divisum. The results of correlation between forage quality parameters and growth stages of the studied species showed a significant negative correlation between dry matter digestibility and growth stage progress in the first three species but it was not significant for Cymbopogon olivieri. CP and ash showed a significant negative correlation with the progress of time in all three studied species. However, CF and ADF were positively correlated with the progress of time.