This study was carried out, utilizing three fistulated Kedah-Kelantan cattle, to investigate the feeding value of three oil palm by-products, i.e., palm press fiber (PPF), palm kernel cake (PKC) and palm oil sludge (POS), by determining the degradation patterns in the rumen under three different feeding programs.
　The disappearance (in %) of PPF from the nylon bag after 48 hr of incubation was lower than that of PKC and POS for dry matter (DM), crude protein (CP) and crude fiber (CF). Especially, DM and CF disappearance was extremely low (17.7-22.4% for DM and 10.5-11.9% for CF). Therefore, it is necessary to improve the fiber digestibility of PPF by proper processing to increase the nutrient content of OPR.
　PKC and POS were ranked as the same type as dehydrated alfalfa meal which showed relatively small value of fraction a, but large value of fraction b and the medium degradation rate c in regard to degradation properties of the protein.
　It was concluded that OPR is a good ration for KK cattle weighing approximately 250 kg. However, to make it better the digestibility of PPF has to be improved by proper treatment. In this connection, it is considered that the organic matter digestibility of PPF would be improved by steaming or explosive-depressurizing treatment.