PHOSPHORUS FORMS IN ANIMAL MANURE

The proportion of inorganic (P-i) and organic (P-o) P in animal feces is affected by rearing conditions. This study was conducted to evaluate the P status of farm animal wastes and the effects of some management factors. Total (P-l), P-i, residual (P-r), acid-soluble organic (P-uso), and lipid (P-l), P were determined in freeze-dried ground (2 mm screen) samples of fresh, uncontaminated daily (Bos taurus L.), beef (Bos taurus L.), hog (Sus scrofa domestica L.), and poultry (Gallus gallus domesticus L.) feces from commercial farms collected during the winter. Additionally, feces from calves (Bos taurus L.) fed cut-1 and cut-2 of three cultivars of reed canarygrass (Phalaris arundinacea L.) and one cultivar of timothy (Phleum pratense L.) were analysed. Total P varied from 6.7 g kg(-1) for feeder cattle feces to 29.1 g kg(-1) for hog feces on a dry-matter basis. Of P-l, P-i ranged from 34.8 (broilers) to 63.2% (dairy), P-r from 11.0 (broiler) to 40.8% (finisher beef), P-aso from 7.8 (diary) to 53.4% (broilers), and P-1 from om 0.4 (hog) to 2.1% (feeders). Dry matter ranged from 14.3 (dairy) to 67.5% (broilers). Ruminant feces varied more in P-l, P-aso, and P-l but less in P-i and P-l than non-ruminant fecal material. Total P and P-i were closely related. Fecal P-i and P-l were higher in cut-2 hay than in cut-1. Calves fed timothy forage produced feces with less P-i than those fed reed canarygrass. Some calves on cut-2 forage produced feces with lower P-l and less P-r on cut-1 material than other animals. Published values were found to be unreliable indicators of fecal P status.