Pollution problems caused by monogastrics occur primarily because of the high numbers of pigs and poultry either in a given area or on individual intensive units. There is a total of approximately 7.6M pigs and 162M poultry which have a total excreta output of about 9.4M tonnes from pigs and 4.6M tonnes from poultry. This is equivalent to a total nitrogen content of approximately 76 and 112 thousand tonnes and a total phosphate content of 47 and 96 thousand tonnes for pigs and poultry respectively. These levels of nitrogen and phosphate are based on chemical analyses of large numbers of slurry and manure samples as spread.