Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: February 1, 2012
Publication Date: July 31, 2013
Citation: Russelle, M.P. 2013. Manure concerns -- pathogens, antibiotics, and other chemicals. In: Bittman, S., Hunt, D., editors. Cool Forages: Advanced Management of Temperate Forages. Pacific Field Corn Assn., Agassiz, BC, Canada. p. 150-151. Technical Abstract: Manure is a fantastic resource for farmers – brown gold, as some have called it – but its use is not without problems. These problems arise because of what the manure contains but may be important only under certain field conditions. Manure application to forages may enhance the spread of pathogenic organisms within a herd or, if the forage is sold, to other herds. Many pathogens excreted in feces live for several months under field conditions. Although ensiling greatly reduces pathogen populations in contaminated forage, the best approach is to apply manure beneath the soil surface and preferably to seed or grain crops, rather than to forage crops. Many classes of livestock receive antibiotics prophylactically or as antimicrobial growth promoters, and 30 to 90% of the administered antibiotics can be excreted in manure. These excreted antibiotics promote the development of antibiotic-resistant bacteria. Composting or other manure treatment may help reduce transmission. Hormones and hormone mimics are natural compounds that also are present in manure. Extremely low concentrations of some hormones can disrupt development of invertebrates and fish. Composting may decrease hormone concentration and activity. Finally, deep soil cracks above subsurface tile drains facilitate the rapid movement of manure constituents to surface water. Farmers and commercial manure applicators need to be aware of these and emerging problems with use of manures in order to reap greatest benefit from the manure and to reduce adverse impacts on the farm operation, the environment, and the public.