Nutritive Evalution of Forage Plants Grown in South Sulawesi, Indonesia

In order to evaluate the nutritive value of the forage plants in South Sulawesi, Indonesia, 266 samples (61 grasses and 65 legumes grown in the dry season, 60 grasses and 80 legumes grown in the rainy season) were collected from the highland and lowland in 1998 to 2000, and were subjected to the determination of chemical composition and digestibility. The least-squares analysis of variance demonstrated that the in vitro dry matter digestibility (IVDMD) of grasses was not significantly affected by season or altitude. On the other hand, the some proximate components and cell wall components were significantly affected by season and altitude including the season x altitude interaction. For the legumes, the in vitro neutral detergent fiber digestibility (IVNDFD) and cellulose content were significantly affected by season. On the other hand, the ether extract (EE) content was significantly affected by season and altitude. The interaction of the seasonxaltitude for IVDMD, of the year x season for some proximate components and of the year x season and the season x altitude for some cell wall components were significant. These results indicate that the forages grown at highland in dry season have a relatively high quality. The means of the total digestible nutrient (TDN) content estimated from IVDMD in grasses and in legumes were 50.3% and 57.4%, respectively, and the crude protein contents were 7.7% and 17.6%, respectively. The correlation coefficients between IVDMD and the contents of crude fiber, neutral detergent fiber and acid detergent fiber were relatively high in all of forage plants, suggesting that these components would provide an accurate prediction of digestibility or TDN content. A close relationship between IVNDFD and lignin content indicates that the lignin would be the most accurate predictor of cell wall digestibility.