Forage accumulation and nutritive value in extensive, intensive, and integrated pasture-based beef cattle production systems

Context A challenge for the livestock sector is to improve the production and nutritive value of forage grasses through sustainable management strategies. Aims This study evaluated the impact of management on the productive and nutritive value of five pasture-based production systems: irrigated pasture with 600 kg nitrogen (N) ha−1 (IP600); rainfed pasture with 400 kg N ha−1 (RP400); rainfed pasture with 200 kg N ha−1 (RP200); silvopastoral with 200 kg N ha−1 (SP200); and degraded pasture without N fertilisation (DP0). Methods During two experimental years, samples were collected pre- and post-grazing to determine forage and nutritional parameters. Land-saving effects and efficiencies of N fertilisation and water use were calculated. Key results For C4 grasses, forage mass accumulation was greater for IP600 and RP400. IP600 also presented the greatest leaf area index and crude protein concentration, whereas DP0 presented the lowest values of both. For C3 grasses in the IP600 treatment, greater forage mass accumulation and leaf area index were found in winter than in autumn; all nutritional characteristics were not affected by season of the year. For land-saving effect, and N- and water-use efficiencies, IP600, RP400 and RP200 presented higher values than DP0 and SP200. Conclusions More intensified systems with proper management allowed better productive and nutritional characteristics than degraded pasture or silvopasture, especially during seasons with greater precipitation or when irrigated. Implications Intensification practices make better use of natural resources (water and land) and agricultural inputs (N fertiliser) to ameliorate the effects of seasonality and improve quality and productivity of tropical grasses in pasture-based livestock production systems.