To have higher profits and sustained production of livestock it is important to understand the biomass accumulation (BMA) and growth rate (GR) of the forages the animals feed on. This work looked into the nutrient content at various growth stages and biomass accumulation of forage maize (Zea mays), forage millet (Echinochloa utiliz), elephant grass (Pennisetum purpureum), and gamba grass (Andropogon gayanus). Experiment was conducted between July and August at a location within Federal University Oye-Ekit, Ekiti State, Nigeria. Planting was done using completely randomized design (CRD) in 4-rows with 4 replicates. Plot size was 27 × 72 cm. Linear additive model was used to test for the effect of the grass specie and the effect of age of cuting on the final BMA of individual cuttings. Harvest was done biweekly starting from 2 wk after planting until wk 8 of planting when experiment was terminated. Highest growing grass in terms of plant height and sward height was Pennisetum purpureum throughout the period of carrying out this experiment. Zea mays had significantly higher values in leave width (5.44 cm at 8 wk) and number of leaves (8.67 cm at 8 wk) during the experiment when compared with other grass species P < 0.05. At the end of 8 wk; Zea mays had the highest BMA of 114%, Echinochloa utiliz had a BMA of 51.31%. Andropogon gayanus had a BMA of 45.53%, Pennisetum purpureum had a BMA of 44.32%. Samples from the last cuttings (wk 8) had the highest CP content (11.88% in Andropogon gayanus) although there was no significant differences between the CP levels of the different species statistically P > 0.05. Crude protein was found to increase nearly linearly as the grasses grew. Crude fiber content of the 3 grass species was observed to undulate as the grasses grew although there was no significant difference P > 0.05 between the species. Crude fiber, moisture content and the fat content all followed the same irregular patterns and there was no significant differences P > 0.05 between their percentage compositions in all the plant samples. In conclusion, GR reduces with increasing BMA.