TY - JOUR AU - Valles de la Mora, Braulio AU - Castillo-Gallegos, Epigmenio PY - 2018/09/03 Y2 - 2024/03/28 TI - Nitrogen balance of bullocks fed Cratylia argentea and Brachiaria arrecta Hay JF - Ecosistemas y Recursos Agropecuarios JA - Ecosist. Recur. Agropec. VL - 5 IS - 15 SE - ARTÍCULOS CIENTÍFICOS DO - 10.19136/era.a5n15.1491 UR - https://era.ujat.mx/index.php/rera/article/view/1491 SP - 523-536 AB - <p>Four experimental diets or treatments formed with incremental proportions of the foliage of tropical shrub legume <em>Cratylia argentea</em> and decremental proportions of Tanner grass (<em>Brachiaria arrecta</em>) hay: T1, 0:100; T2, 15:85; T3, 30:70; and T4, 45:55 were evaluated using four Holstein-Zebu bullocks (214.5 9.3 kg) conned in individual pens, under a balanced 4 x 4 latin square design. The crude protein (CP, %) content of <em>C. argentea</em> was 19.3 ± 6%, and in the grass was 6.2 ± 3%. The intake of DM increased as the <em>C. argentea</em> level in the diet increased. Blood urea-N (BUN) showed a linear increase from T1 to T4, observing its highest concentration at feeding time and six-hours after in T4: 12.00 and 14.75 mg dL<sup>-1</sup>, respectively. Purine derivatives (uric acid and allantoin) were not affected by treatments (p &gt; 0.05). The increase of the legume in the diet improved the DM intake and digestibility, and led to N-balance from negative in T1 and T2, to positive in T3 and T4. The legume proportion in a basal diet of the grass <em>B. arrecta</em> must be 30% at least.</p> ER -