Palisadegrass pastures with or without nitrogen or mixed with forage peanut grazed to a similar target canopy height. 2. Effects on animal performance, forage intake and digestion, and nitrogen metabolism

The lack of nitrogen (N) input on pastures is the main limiting factor to increase animal performance in tropical regions. This 2.5-year study assessed animal performance, forage intake and digestion, and N metabolism responses of three pasture treatments: (1) mixed Marandu palisadegrass-Brachiaria brizantha (Hochst. ex A. Rich.) R.D. Webster (syn. Urochloa brizantha Stapf cv. Marandu)-and forage peanut (Arachis pintoi Krapov. & W.C. Greg. cv. BRS Mandobi) pastures (GRASS + LEGUME), (2) monoculture Marandu palisadegrass pastures with 150 kg of N/ha (GRASS + N), and (3) monoculture Marandu palisadegrass without N fertilizer (GRASS). Continuous stocking with variable stocking rate was used with a target canopy height of 20 to 25 cm. The average daily gain was greatest at GRASS + N and GRASS + LEGUME (p = .081). GRASS + N pasture had greatest stocking rate and liveweight gain per area (p p < .001, respectively), followed by GRASS + LEGUME pasture. No differences between treatments were found for the dry matter forage intake (p = .729); however, GRASS + N and GRASS + LEGUME pastures had greater crude protein and digestible organic matter intakes than GRASS pasture (p = .007 and p = .083, respectively). Greatest microbial protein synthesis and efficiency of microbial synthesis were found for GRASS + N and GRASS + LEGUME pastures (p = .016 and p = .067, respectively). Apparent efficiency of N utilization and microbial protein/CP intake ratio was greatest at GRASS + LEGUME pastures (p = .009 and p = .042, respectively). Nitrogen application or the integration of forage peanut in grass pasture increases animal performance, forage digestibility, and microbial protein synthesis.