摘要:Background and Objectives: Palm oil waste can be used as an alternative feed for ruminants. Optimizing the utilization of palm oil waste for ruminant feed can be accomplished through feed processing, such as fermentation. The objectives of this research were to determine the best effect of a fermented palm by-product-based ration on rumen parameters [ammonia (NH3) and volatile fatty acid s (VFAs)] and feed digestibility [total digestible nutrients (TDN)] and digestibility of dry matter , organic matter , protein and crude fibre, in Ongole cattle. Methodology: This study utilized a random block design and was based on weight gain. The design included 3 treatments and 3 replicates; thus, nine cattle were included. The treatments tested in this research were a control ration (R0; rice straw, cassava waste, coconut meal, rice bran, molasses, urea and premix), non-fermented palm oil by-product-based ration (R1; cassava waste, rice bran, molasses, urea and premix+palm leaves and palm kernel meal) and fermented palm oil by-product-based ration (R2; cassava waste, rice bran, molasses, urea and premix+palm leaves and palm kernel meal). Results: Rumen liquid VFA and NH3 concentrations were highest at 110 and 6.74 mM, respectively, after treatment with non-fermented palm oil waste. Feed digestibility parameters (TDN and digestibility of dry material and organic material) were highest after treatment with fermented palm oil waste, with values of 82.94, 69.75 and 75.69%, respectively. The highest digestibility of protein was obtained with the control ration. Conclusion: Palm oil waste-based rations significantly increased rumen liquid NH3, rumen liquid VFA, the digestibility of dry and organic material and TDN. The R2 treatment had the best effect on TDN and the digestibility of dry matter , organic matter and crude protein .