Effect of antimicrobial agents on livestock waste emissions

Various antimicrobial agents were evaluated with the purpose of reducing th e microbial fermentation in stored cattle waste and the resulting odor emis sions. Duplicate sealed 2-L flasks with 500 mi waste slurry, with and witho ut antimicrobial inhibitors, were used to measure the production of short-c hain volatile fatty acids, lactate, and total fermentation gas over 27-30 d ays. A combination of chlorhexidine diacetate (2 mM), iodoacetate (2 mM), a nd alpha-pinene (3.8 mM) reduced gas production 80% (1000 mi to 200 mi) and total volatile fatty acid production 50% (145 mM to 72 mM), Pinene had lit tle antimicrobial effect;; rather, it served as an effective masking agent, giving the waste a less offensive odor. A combination of chlorhexidine dia cetate and the deaminase inhibitor, diphenyliodonium chloride (1.3 mM) had a similar effect in reducing short-chain volatile fatty acid production (14 5 mM to 80 mM). Tt is concluded that a combination of antimicrobial agents may be useful in controlling odor emissions and conserving organic matter i n livestock wastes, therefore providing a potentially more useful byproduct waste when used as plant fertilizer.