Nutrient intake and economic analysis of young bulls reared in silvopastoral systems with babassu palm trees in the Pre-Amazon region

Abstract

This study evaluated the intake of dry matter (IDM), nutrients and the economic analysis of F1 young bulls from the cross between Nellore and Guzera on pastures of Urochloa brizantha cv. Marandu in silvopastoral systems composed of babassu palm (Attalea speciosa) and Marandu monoculture in the Pre-Amazon region of the state of Maranhão. Animals were evaluated in four systems consisting of 0, 80, 131, 160 palms ha-1, characterizing monoculture (MC), low density of palm trees (LDP), average density of palm trees (ADP) and high density of palm trees (HDP) during the rainy (RP) and dry (DP) periods. The dry matter intake, in g day-1, %BW and g kg-0.75 was influenced by the densities of babassu palm trees (P < 0.05). In both evaluation periods, the animals kept on monoculture consumed more forage. Animals kept on HDP consumed greater amounts of CP in both periods, approximately 478.20 and 599.18 g day-1 for DP and RP, respectively. The intake of NDF was affected by periods and palm densities (P < 0.05). There was a higher intake of NDF for animals kept on MC, in both periods. Of the four systems evaluated, only LDP resulted in a revenue per hectare higher than the costs, making it the only profitable system. However, in a five-year simulation, all systems resulted in an internal rate of return higher than 6,87% the rate of attractiveness, and the LDP system had the best result. All analyzed systems had a benefit/cost ratio greater than one; i.e., all are economically viable.