The basic diet of ruminants in Mauritius comprises mainly tropical forages, whose productivity is highly dependent on the season. Dry matter concentrations and nutritive value of the three most important grasses (Bothriochloa pertusa, Cynodon plectostachyus and Ischaemum aristatum) on Mauritius were measured on three occasions during the year. They showed an increase in dry matter concentration and a decrease in nutritional value at the end of the dry season, more marked for farms located in the coastal region. To allow animals to meet their nutrient requirements, farmers have to adapt their practices (supplementary feeding, rotational grazing, and fertilization) to the seasonal changes on the island.