Compostagem dos dejetos da bovinocultura de corte: Influência do período, do genótipo e da dieta

Abstract

The objective of this study was to identify possible alterations in composition and in the composting process of manure produced by Canchim and Nellore cattle in different periods of feedlot and fed different forage to concentrate ratios. The experiment was carried out in complete randomized design in factorial scheme with time as subdivided plot. Plots were established by four treatments: manure from two diets (40% forage and 60% concentrate and 60% forage and 40% concentrate) and two genotypes (Canchim and Nellore) and sub-plots by three periods of manure gathering (initial, intermediate and final). The efficiency of composting process was evaluated by reductions of volume, total solids, volatile solids, fibrous fraction, organic carbon and temperature, besides the most probable number of total and thermotolerant coliforms and contents of nitrogen and macro and micro minerals. There was no effect of genotype and period on manure composting; however, the increase in the roughage level in the diet promoted the lower efficiency of the process. Decrease of 100% in the most probable number of total and thermotolerant coliforms and increase in the nutrients content of the final compost were observed. © 2012 Sociedade Brasileira de Zootecnia.