It was evaluated the effects of age of the animal and of the proportion of dietary roughag on anaerobic biodigestion of the manure of Saanen kids. It was used the feces produced by Saanen kids at 90, 120 and 150 days of age and fed diets with three roughage:concentrate ratios (80:20, 60:40 and 40:60), representing diets 1, 2 and 3, respectively. It was used batch digesters of bench with capacity for 12 liters of substratum in fermentation process and 8% of initial total solids for determination of biogas and methane productions and production potentials, and reduction of volatile solids and quantification of mineral contents in affluent and effluent. The greatest volatile solid reductions were observed in substrata prepared with feces of goats at 150 days of age fed diets with roughage:concentrate ratio of 40:60. The best results of substratum or feces were obtained with manure of goats at 120 and 150 days of age fed diet with 40:60 roughage:concentrate ratio. The greatest concentrations of minerals in the biodigesters were observed for feces of goats at 150 days of age fed the diet 40:60 roughage:concentrate ratio. Anaerobic biodigestion is efficient in removing coliforms from goat manure, providing effluents with maximum of 4.3 × 10² of total and thermotolerant coliforms per gram of material.
biogas; goat; methane; recycling
