ABSTRACT
Although cattle drinking water requirements are significant, averaging 10.8 gal hd1day1,[1] the beef cattle sector of America’s $100 billion yr1 animal agriculture industry uses relatively little water for manure management. The vast majority (perhaps 98%) of the nation’s average of 10.3 million head of cattle on feed for slaughter and beef processing are fed in open, soilsurfaced feedyards. As a result, nearly all feedyard manure is collected in solid form. With an average turnover rate of 2-2.3 times per year, over 20 million head of cattle are fed in this manner, generating roughly a ton of as-collected manure per head fed and harvested. In the typical beef cattle feedyard, all manure deposited on the feedlot surface undergoes concurrent processes of: a) partial evaporative drying (from 75 þ % wet basis as-excreted down to 20-50% wet basis as-collected); b) partial decomposition of volatile organic solids; and c) atmospheric release of gaseous compounds that include carbon dioxide, volatile organic compounds, and ammonia.
