The effect of using dung from cattle fed high-, low-or no-concentrate rations, on the quality and nutritive value of slurry from a biogas plant

Abstract

The dung from cattle fed a high-concentrate ration, a low-concentrate ration and an all-roughage ration contained 10, 7 and 5·9% crude protein. After anaerobic digestion of these excreta in a biogas plant, the crude protein content of the slurry produced was in every case increased to 15%. Slurry produced by the digestion of poor quality dung (5·9% CP) was incorporated with wheat straw and molasses in a feed for buffalo bulls. The digestible crude protein and total digestible nutrients contents of slurry were found to be 7·6 and 38% respectively, indicating that about 50% of protein of the biogas slurry was digested. The animals maintained weight on this feed. The biogas slurry was free from pathogenic organisms. Anaerobic digestion can upgrade the excreta from cattle fed on poor-quality rations, common in India and other developing countries, to give a material which could be used as a cattle feed ingredient, at least during a temporary shortage of conventional feeds.