Study on Nutritive Value of Tropical Forages in North Sumatra, Indonesia

This study was conducted to evaluate nutritive value of forages commonly used as ruminant feeds in North Sumatra, Indonesia. Seven species of grasses and five species of legumes were collected during the rainy season. The results showed that chemical composition, in vitro digestibility of dry matter (DMD), organic matter (OMD) and crude protein (CPD), in vitro gas production and metabolizable energy (ME) content greatly varied among the species of grass and legume forages. The CP content ranged from 6.6 to 16.2% in grass and from 17.5 to 29.1% in legumes; while NDF content of grass and legume ranged from 57.2 to 66.2% and from 24.4 to 55.6%, respectively. The DMD, OMD and CPD of grass ranged from 49.1 to 62.2%, 51.9 to 64.4% and 50.5 to 60.3%; while in legumes the values ranged from 59.1 to 71.8%, 65.2 to 72.0% and 68.2 to 71.6%, respectively. The ME content of grass varied from 6.4 to 9.3 MJ/kg and from 6.5 to 8.3 MJ/kg for legumes. In general, within species of grass Cynodon plectostachyus contained higher CP but was lower in NDF that resulted in much higher digestibility; a similar result was also found in Leucaena leucocephala for the legumes. The two forages also contained much higher ME than the others. In conclusion, the nutritive value of forages in North Sumatra, Indonesia during the rainy season was relatively high as ruminant feed, with the best quality noted for Cynodon plectostachyus and Leucaena leucocephala.