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United States Department of Agriculture

Agricultural Research Service

Title: Plant Oils and Urease Inhibitors As Solutions for Environmental Issues Associated with Confined Animal Feeding Operations

item Varel, Vincent
item Wells, James

Submitted to: Conference on Gastrointestinal Function
Publication Type: Abstract Only
Publication Acceptance Date: February 16, 2005
Publication Date: April 12, 2005
Citation: Varel, V.H., Wells, J. 2005. Plant oils and urease inhibitors as solutions for environmental issues associated with confined animal feeding operations. Proceedings of the 2005 Conference on Gastrointestinal Function. p. 28.

Technical Abstract: Air quality and transmission of pathogens are concerning issues for confined animal feeding operations (CAFOs). The objectives of our work are to evaluate urea hydrolysis, VFA production (odor), and fecal coliforms in cattle waste slurries after a urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) and a plant oil of lower cost than thymol, i.e., alpha-terpineol or plinol, are added. Feces from cattle fed a diet of 83% corn were blended with urine and distilled water (50:35:15). Triplicate aliquots were amended with additives, reblended, and poured into 1.6 L wide-mouth jars covered 90% with a lid. Treatments were sampled periodically out to 56 days. Thymol, terpineol, or plinol (2000 mg/kg waste) in combination with NBPT (80 mg/kg waste) did not prevent hydrolysis of urea beyond that of NBPT by itself. Essentially all urea (4.0 g/kg waste) was converted to ammonium after 21 days; whereas, with no NBPT this usually occurs after one day. Fecal coliforms (6.41 log10 CFUs per g, day 0) were immediately eliminated with thymol, and by day 4 with terpineol and plinol. No lactate accumulated in the waste treated with thymol; however, 250 mM lactate accumulated in the terpineol and plinol treatments, and 230 mM in the untreated waste. Minimal VFA (60 mM) accumulated in the thymol treatment, compared to 200 mM in the untreated waste and 80 to 120 mM in the terpineol and plinol treatments. It is concluded that terpineol and plinol may offer lower cost amendments for cattle waste emissions than thymol; and, they allow lactate to accumulate in the waste which keeps the pH lower and further inhibits microbial activity.

Last Modified: 4/18/2015