Intensification of pasture-based livestock systems: environmental benefits, forage availability, nutritional value and Nellore cattle performance

Silvopastoral systems have been acknowledged as efficient generators of important environmental benefits, worldwide, improving pasture quality and providing thermal comfort and animal welfare, when in comparison to traditional monoculture pasture systems. In this sense, an experiment was carried out to assess forest component inclusion to intensify pasture-based livestock systems. For that, the microclimate was monitored, and the Heat Load Index was estimated, forage production and nutritional values were assessed, Nellore cattle performance and enteric methane emissions were estimated and carbon stock in the stem of eucalyptus clones AEC 144 (Eucalyptus urophylla) and AEC 2034 ((Eucalyptus camaldulensis x E. grandis) x E. urophylla) were calculated. The analyzed eucalyptus clones were distributed in simple–line rows (2 × 25 m; 155 trees ha⁻¹) under silvopastoral system set with Urochloa (syn. Brachiaria) brizantha cv. Piatã to be compared to traditional monoculture pasture system set with Urochloa brizantha cv. Marandu. The silvopastoral system led to microclimatic conditions accounting for better thermal distribution and for fewer daily heat–accumulation hours over the 2 year study. Forage production and nutritional value were significantly higher and seasonally stable, and it led to better animal performance per area than the traditional system. Furthermore, enteric methane emissions were lower during the rainy season and the forest component had positive influence on the carbon stock in stems. Thus, using trees to intensify pasture-based livestock systems improves animal performance gain by neutralizing enteric methane emissions, promoting better thermal distribution and greater stability in forage production and nutritional value.