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.

为了进一步发展热带地区的牲畜生产，需要有效利用当地可用的饲料资源。然而，滋养草的供应不足是普遍现象，而且关于不同季节当地可用饲料资源的化学成分和消化率的信息有限。关于菲律宾干旱和雨季禾本科资源营养价值的可靠信息很少。因此，本研究旨在确定菲律宾在干旱和雨季的9种当地可用的禾本科饲料资源的化学组成和体外消化率。草样品中干物质（DM），粗蛋白和粗纤维的浓度在物种和季节之间没有差异。有机物浓度（OM）除雨季NDF以外，两个季节的草样品中，乙醚提取物（EE），粗灰分（CA），无氮提取物（NFE），酸性去污剂纤维和中性去污剂纤维（NDF）均存在显着差异。但是，样品的OM，CA和NDF浓度在各个季节之间没有差异。在样品中圆柱状白茅显示出最高的OM浓度。腕带Brachiaria brizantha的EE浓度最低。最低的NFE浓度在草中的Panicum最大值中被确定。尽管草样品的DM（DMD），OM（OMD）和NDF（NDFD）的消化率在物种之间显示出显着差异。尽管紫草狼尾草的DMD，OMD和NDFD含量最高，但水I的DMD，OMD和NDFD最低。在当前调查区域的样本中，紫菜的营养价值相对较高。