Implementation of silvopastoral systems in Brazil with Eucalyptus urograndis and Brachiaria brizantha: Productivity of forage and an exploratory test of the animal response

The loss of productive capacity of pastures has a direct impact on livestock productivity and there is an inefficient use of natural resources. In this scenario, a production strategy that can reverse this degradation is the use of silvopastoral systems. This study aimed to evaluate the animal performance associated with the Piatã grass traits under open pasture and two silvopastoral arrangements in the Brazilian Cerrado. The forage was Brachiaria brizantha cv. BRS Piatã, and the tree species was the Eucalyptus urograndis (Eucalyptus grandis x E. urophylla) planted in the North-South direction in the treatments: forage grown in treeless area (control); forage grown in eucalyptus understory with 22 m spacing between rows (SSP22); forage grown in eucalyptus understory with 12 m spacing between rows (SSP12). There was a higher availability of forage dry mass of Piatã grass in the treeless treatment in the rainy and dry seasons, and treatment SSP22 was superior to SSP12 in the rainy season. SSP12 and SSP22 pasture presented the highest content of crude protein and the lowest forage density. The leaf/stem ratio and in vitro dry matter digestibility were higher in control compared to SSP12. Cell wall components were affected by the season, but not by the treatments. The stocking rate was higher in the treeless treatment and the average daily gain of animals did not differ between treatments. The live weight gain per area (hectare) was higher in SSP22 compared to SSP12 and both were lower than the control. Chemical and structural characteristics of Piatã grass were affected by silvopastoral systems, which directly influenced animal performance. If livestock production is the only goal, spacing between tree rows not less than 22 m should be prioritized under silvopastoral system with eucalyptus trees planted in the North-South direction.