Partitioning of Animal Feed Nitrogen into Excreted Solid Waste and its Recycled Products

The present study was designed aiming to quantify the daily feed intake and voided amount of adult beef animals and the future potentiality of voided material through following proper recycling methods. An animal trial was arranged to quantify the sum of daily intake and outgo of 10 individual animals separately. Regular dung and urine were collected in a separate bucket and weighed at every 24-hours interval using a digital weighing balance. Laboratory scale anaerobic digestion of solid dung was continued up to 60 days and the total gas and slurry production was quantified. Results showed that about 7.84 kg feed DM and 0.83 kg N were consumed by each animal daily of which 33% of consumed feed volume became lost in solid dung where the excreted DM extent was 25%. In the case of nitrogen, the losing range was 42.2%. 1kg solid dung mixed with an equal amount of water produced 0.03 cubic meter biogas and 1.86 kg bio-slurry from the digestion anaerobically. The gas production trend was somewhat slow in the first week which started to increase up to 4th week. Only 27.78% DM of supplied feedstock was used during gas production and the remaining portion come out from the digester as residue. The DM and N of fresh bio-slurry was 7.0 and 2.31% respectively and the recovered N in the fresh slurry was 100 times higher than fresh dung. The amount of lost feed nitrogen and its future probable potentiality can be defined through this study