Date of this Version
A commercial feedlot study determined manure nutrient flow in six feedlots using a corn and by-product based diet with an average P content of 0.39% (DM basis), and a range of 0.34 to 0.48%. Mass balances for N and P were conducted on each pen. The average feed nutrient intake was 0.52 lb N/head/day (64.0 + 7.6 lb/animal fed) and 0.09 lb P/head/day (10.9 + 2.2 lb/animal fed). Based upon averages from the 6,366 head of cattle, 11.5% of the feed nitrogen and 16.9% of the feed phosphorus were retained by the animal with the remaining nutrients excreted. The harvested manure averaged 73% dry matter and 28% organic matter. A wide range of observed organic matter levels (9 to 63%), reflected soil being hauled out of pens along with the manure solids. Based upon these data, 31% of the excreted nitrogen or (17.2 lb/animal fed) and 90% of the excreted phosphorus (or 8.1 lb/animal fed) were removed in manure at cleaning.