Nutritional value of Brachiarias and forage legumes in the humid tropics of Ecuador
This research evaluated the nutritional value of five varieties of Brachiarias: B. decumbens Stapf; B. brizantha Marandú; B. brizantha Piatá; B. brizantha Xaraés; and Mulato II [B. ruziziensis × B. brizantha]). The Brachiarias were combined at different inclusion rates (0, 10 and 15%) with two tropical forage legume species (Centrosema pubescens and Cajanus cajan, ECV22). The samples were collected at the experimental farm, The Oasis, a property of the Universidad Tecnológica Equinoccial (Ecuador), with 42 d of regrowth for the Brachiarias and 150 d for the legumes in the dry season. The proximate analysis and the Van Soest procedure were performed in the laboratory of food science and animal nutrition of the Escuela Superior Politécnica de Chimborazo (Ecuador). The in situ digestibility of dry matter (ISDDM) was assessed in three Holstein cows (560 ± 23 kg) with ruminal cannula. The proximal and Van Soest variables were analyzed with a complete randomized design, and for the variable ISDDM, a randomized block design was used. Significant differences for ISDDM (P≤0.05) between the Brachiaria varieties were found, with the highest percentages for the cv. B. decumbens Stapf and B. brizantha Marandú (63.9 and 63.2%, respectively). The diet with 10% C. cajan had average percentages of CP, NDF and ADF of 8.7, 70.7 and 47.6%, respectively, for all the Brachiaria varieties used in the study. It was found that diets with B. decumbens and B. Mulato II plus 10% of C. cajan were the best in terms of CP, NDF, ADF and ISDDM (9.3, 70.5, 46.4 and 64.1% and 8.6, 69.9, 50.3 and 63.5%, respectively). The results of this research showed that the value of CP meets the minimum requirements of nitrogen in the ration and that the ISDDM, DM, CF, NDF, ADF and ADL values are within the ranges reported for the genus Brachiaria.