Author
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Varel, Vincent |
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Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only Publication Acceptance Date: 3/31/2001 Publication Date: 7/26/2001 Citation: Varel, V.H. 2001. Livestock odor abatement with plant-derived oils and urease inhibitors [abstract]. Journal of Animal Science. 79(Suppl. 1):97. Interpretive Summary: Technical Abstract: Confined animal feeding operations are under environmental scrutiny for production of large quantities of waste in a small area. The waste can result in odor, global warming gases and the transfer of nutrients and pathogens to water and food sources. An incomplete anaerobic degradation of the carbohydrate, protein, and lipid components in waste is the primary cause of odor emissions. Our objectives are to provide simple, cost effec tive, and environmentally sound solutions to control odor and pathogens in livestock waste, with nutrient management a top priority. A urease inhib- itor, N(n-butyl) thiophosphoric triamide, was used to reduce urea hydroly- sis in beef cattle feedlot pens, conserve nitrogen, and inhibit ammonia emissions which contribute to odor. Laboratory studies with antimicrobial plant-derived oils, thymol and carvacrol, at 2 g/kg of feedlot waste completely inhibited the production of VFA in flasks over 42 days. Fecal coliforms were reduced from 4.6 * 10**6 to 2.0 * 10**3 cells/ml 2 days after treatment, and were nondetectable within 4 days. Total anaerobic bacteria were reduced from 8.4 * 10**10 to 1.5 * 10**7 cells per ml after 2 days and continued to be suppressed to that level after 28 days. Our feedlot studies and the literature indicate these oils are degraded under aerobic conditions. This suggests that these generally recognized as safe (GRAS) chemicals, which are routinely used as preservatives in food and personal care products, should not accumulate in soils to which this waste is applied. It is concluded that chemical additives can be added to animal waste to prevent degradation, which in turn controls odor emissions, reduces pathogens, and conserves nutrients until the waste can be recycled as fertilizer. |
