Potentials of biogas production from young bulls manure fed with different diets

Physical and chemical characteristics of manure are modified by different animal production systems. In cattle feeding system for young bulls there is an inversion of the proportion between forage and concentrate. In other words, the animals receive a smaller amount of forage compared to the traditional system. These changes in the manure characteristics involve changes in the treatment systems. The aim of this study was to determine the potential production of biogas of batch digesters fed with manure from young bulls that received two diets containing different proportions between forage and concentrate, with or without inoculums and submitted to three levels of temperature (25, 35 and 40(0)C). The evaluated parameters were total solids (TS) and volatile solids (VS) reduction and biogas potentials production. The digesters fed with manure from animals that received the diet 2 (80%C + 20% R) showed the largest reductions of TS and VS. About the potentials of biogas production there was interaction between the factors diet and inoculums, but no effects of temperatures. The treatment content manure from animals fed with diet 2 without inoculums presented the greatest potential of biogas production per kg of TS added (0.2123 m³)