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Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan

Citation:  Pp. 377-408 in Animal Agriculture and the Environment: National Center for Manure and Animal Waste Management White Papers. J. M. Rice, D. F. Caldwell, F. J. Humenik, eds. 2006. St. Joseph, Michigan: ASABE.  .(doi:10.13031/2013.20259)
Authors:   A. Sutton, T. Applegate, S. Hankins, B. Hill1, D. Sholly, G. Allee, W. Greene, R. Kohn, D. Meyer, W. Powers, T. van Kempen

Manure is composed of feces, bedding, wasted feed, and runoff water. Most of manure nutrients come from urine and feces excreted from animals that contain undigested components from their diets, excretion end products from normal metabolism, and bacterial cells from indigenous bacteria in the digestive tract. The amount and composition of freshly excreted manure can vary and is primarily influenced by the original composition of the diet. Diet ingredient sources, forms and levels can influence nutrient availability, excretion levels and forms. Because ruminants (including beef cattle and dairy cattle in this paper) have different digestive systems compared to nonruminants (including poultry and swine in this paper) excreta volume and composition differs. The digestive tract of a ruminant includes a multi (4)-compartment stomach that possesses a microbial population capable of digesting and releasing nutrients from highly fibrous feeds (forages) or highly digestible grains for the animals use. The nonruminant has a simple stomach (one compartment) that does not efficiently digest highly fibrous feeds, but requires highly digestible grains readily digested by enzymes to release nutrients for the animals use. Understanding the bioavailability of nutrients from feed sources used in the diets is critical for formulating a diet that will meet the productive needs of the animal. Feed management practices can also influence the efficiency of nutrient utilization in livestock and poultry operations. Odorous and gaseous compounds are emitted immediately after excretion due to microbial metabolism in the digestive tract of the animal. Further decomposition during storage can occur resulting in gaseous emissions and odors that have an impact on air quality. Since the animal is the initial source of nutrient excretions and odors from animal operations, diet manipulation is a practical and economical way to control excess nutrient excretions and reduce gaseous emissions. This paper summarizes key research approaches and results related to using diet manipulation to reduce nutrient excretions and minimize odors from livestock and poultry operations. In addition, this paper identifies some information gaps and needed research to fill the voids in information to maintain livestock and poultry production while sustaining environmental stewardship.

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