Two experiments were carried out to evaluate cultivation of Spanish Panicum Mombasa (SPM) in five Cutting interval (CI) 30, 45, 60, 75 and 90 day and its effect on in vitro rumen fermentation and dairy goats performance feeding at 0, 25 and 50% SPM as a replacement of clover hay (CH). 30 days CI recorded the highest values of CP, EE, and ash content being 17.9, 2.1 and 12.7, respectively. The lowest recorded CF content being 24.6%. Regarding in vitro rumen fermentation, methanogenesis trail of samples collecting from different SPM in CI days showed that the lowest gas production (GP) was at 90 days CI. In a performance trail, 24 baladi lactating goats were divided into (T1) control group, (T2) group fed rations supplemented with 25 and (T3) 50% of SPM as a replacement from CH. (T3) ranked the highest milk yield followed by (T2) compared significantly (P