FORAGE LEGUMES INCLUDED IN DIETS WITH TROPICAL GRASSES - I - CHEMICAL-COMPOSITION AND IN-VITRO DIGESTIBILITY

An experiment was conducted to determine the effects of including legu me species (Leucaena leucocephala, Stylosanthes guianensis, Centrosema pubescens Benth or Neonotonia wightii) at levels of 0, 5, 10, 20, and 40% of the dry matter on the chemical composition (crude protein, CP neutral detergent fiber, NDF; acid detergent fiber, ADF) and on in vit ro dry matter digestibility (IVDMD) of mixtures of each legume with fo ur grass species (Cynodon nlemfuensis Vanderyst, Panicum maximum jacq. , Pennisetum purpureum Schum., or Sorghum bicolor (L.) Moench). Of the legume species included, Leucaena leucocephala and Centrosema pubesce ns had the highest CP content and IVDMD, respectively. For the legumes , the mean CP and IVDMD values, respectively, were Leucaena leucocepha la, 21.98 and 68.09; Stylosanthes guianensis, 13.70 and 63.44; Centros ema pubescens, 18.29 and 68.60; and Neonotonia wightii, 16.72 and 66.6 4%. For the grasses, they were, respectively, Cynodon nlemfuensis, 8.2 7 and 61.38; Panicum maximum, 7.64 and 60.06; Pennisetum purpureum, 8. 02 and 53.47; and Sorghum bicolor, 7.57 and 59.62%. Neutral detergent fiber and ADF contents were higher in the grasses (Cynodon nlemfuensis , 73.03 and 44.45; Panicum maximum, 65.27 and 49.06; Pennisetum purpur eum, 69.26 and 51.88; and Sorghom bicolor, 60.24 and 50.99%, respectiv ely) than in the legumes (Leucaena leucocephala, 50.52 and 28.50; Styl osanthes guianensis, 52.57 and 36.63; Centrosema pubescens, 58.43 and 34.84; and Neonotonia wightii, 54.11 and 33.23%, respectively). The ch emical composition of the forages varied according to the relative pro portions of the species included, as expected. However, the effects on IVDMD were not additive; rather, associative effects, mainly antagoni stic, were observed in most of the mixtures.