The effects of three different feeding systems on beef cattle production performance, rumen fermentation, and rumendigesta particle structure were investigated by using 18 Limousin (steers) with a similar body weight (575±10 kg) in a 80-d experiment.The animals were equally and randomly divided into three treatment groups, namely, total mixed ration group (cattle fed TMR), SI1group (cattle fed concentrate firstly then roughage), and SI2 group (cattle fed roughage firstly then concentrate).