Periodic changes in chemical composition and in vitro digestibility of locally available Gramineae feed resources in the Philippines

Efficient utilization of locally available feed resources is needed for further development of livestock productions in the tropics. However, an inadequate supply of nourish grass is common, and limited information exists regarding the chemical composition and digestibility of locally available feed resources in the different season. There were few reliable information concerning nutritive value of Gramineae resources in dry and rainy seasons in the Philippines. Hence, the present study was conducted to identify the chemical composition and in vitro digestibility of nine kinds of locally available Gramineae feed resources in dry and rainy seasons in the Philippines. The concentration of dry matter (DM), crude protein, and crude fiber of grass samples did not differ among species and seasons. The concentration of organic matter (OM), ether extract (EE), crude ash (CA), nitrogen-free extract (NFE), acid detergent fiber, and neutral detergent fiber (NDF) of grass samples differed significantly among species in both seasons except the NDF in the rainy season. However, the OM, CA, and NDF concentrations of the samples showed no differences between seasons. Imperata cylindrica showed the highest concentration of OM among the samples. Brachiaria brizantha had the lowest EE concentration among the grasses. The lowest NFE concentration was identified in Panicum maximum among the grasses. Although the digestibility of DM (DMD), OM (OMD), and NDF (NDFD) of grass samples showed significant differences among species. The DMD, OMD, and NDFD of I. cylindrica were the lowest among the samples, though Pennisetum purpureum showed the highest DMD, OMD, and NDFD among the species. Relatively high nutritive values of P. purpureum were remarkable among the samples in the present survey area.