Title: Environmental considerations of feeding bio-fuel co-products. Authors
|Brown, Michael - WTAMU|
|Macdonald, James - TEXAS AGRILIFE RESEARCH|
Submitted to: American Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: March 9, 2008
Publication Date: July 11, 2008
Citation: Cole, N.A., Brown, M.S., Macdonald, J.C. 2008. Environmental considerations of feeding bio-fuel co-products [abstract]. Abstracts of American Dairy Science Association and American Society of Animal Science Joint Meeting, July 7-11, 2008, Indianapolis, Indiana. No. 148. 2008 CDROM. Technical Abstract: The high concentrations of some nutrients in distiller's grains (DG) make formulation of diets difficult and can lead to environmental concerns. These concerns will differ with feedlot location, feedlot size, diet formulation, and grain processing method used. Feeding DG in dry-rolled corn-based diets (DRC) does not apparently affect DM digestion or total DM excretion; whereas, with steam-flaked corn-based diets (SFC) the feeding of DG decreases DM digestibility. With SFC-based diets the quantity of pen manure collected increased about 10% for each 10% increase in dietary DG concentration (DM basis); whereas it increased 0 to 5% with DRC-based diets. With SFC-based diets, the N and P concentrations of collected manure were not affected by feeding of DG. Phosphorus excretion (and acres of cropland required for manure removal) increases approximately 10 to 25% for each 10% increase in dietary DG concentration. The effects of feeding DG on subsequent ammonia emissions may vary with season and dietary N concentrations. In our studies, N volatilization as a percentage of N intake, decreased about 20% when DG was fed (15 or 20% of DM); however, because of greater N intake, total N volatilization losses (kg/steer) were not affected. During production and storage, DG emit VOC that could potentially contribute to odors or ozone formation. High sulfur concentrations in DG could affect animal health as well as emissions of hydrogen sulfide and other odorants. British and Nebraska studies suggest that feeding of DG can decrease enteric methane production in high-roughage diets; however, the effects in high-concentrate diets are not known. To our knowledge, the effects of feeding DG on excretion of physiologically active compounds (antibiotics, hormones, etc.) have not been studied. In conclusion, it appears that the feeding of DG may have environmental effects that need to be considered when determining ingredient value and optimal diet formulations.