Dairy cattle farming is an important and expanding economical activity in the central Highlands of Madagascar. Elephant grass (Pennisetum purpureum) is by far the most cultivated forage grass due to its adaptation to zero-grazing systems and to a wide range of soil types including acidic. A study was conducted at two sites located in the Vakinankaratra region, in the Highlands of Madagascar to assess the effect of locally available guano organic fertilizer on growth parameters, yield and forage quality of Elephant grass. A randomized complete block design with four replicates was used to compare 3 rates (300, 400, 500kg ha-1) of guano organic fertilizer (4,8N-6,5P-1,2K) with one cattle manure rate (10t ha-1) and one unfertilized control.