Location: Food and Feed Safety Research
Title: Microbiological aspects of applying composted dairy manure to amend damaged rangeland Authors
Submitted to: Society of Range Management
Publication Type: Abstract Only
Publication Acceptance Date: September 22, 2007
Publication Date: February 10, 2007
Citation: Edrington, T.S., Fox, W.E., Callaway, T.R., Anderson, R.C., Nisbet, D.J. 2007. Microbiological aspects of applying composted dairy manure to amend damaged rangeland [abstract]. Society for Range Management, 60th Annual Meeting and Trade Show, February 10-16, 2007, Reno/Sparks, Nevada. p. 90-91. 2007 CDROM. Technical Abstract: Manure production and its subsequent disposal is a continual problem for the livestock producer. Composting manure, if done properly should kill bacteria such as E. coli O157:H7, providing for an environmentally safe product. Recently, large scale application of composted manure to aid in land restoration has been evaluated on damaged rangeland. While the benefits of this practice could be substantial, it is crucial to ensure that such large scale applications are safe and harmonious with the environment. Samples of composted dairy manure, representing 8 composting operations, were screened for the pathogenic bacteria Salmonella and E. coli O157:H7 and were all culture negative. However, some non-pathogenic bacteria were cultured from these compost samples that could theoretically facilitate the spread of antimicrobial resistance from the dairy to compost application sites. Therefore, we collected soil samples from rangeland that received either composted dairy manure (CP), commercial fertilizer (F), or no treatment (control, CON). Two collections were made appoximately 2 and 7 months following treatment application. Soil samples were cultured for Pseudomonas and Enterobacter and confirmed isolates subjected to antimicrobial susceptibility testing. Two species of Enterobacter (sakazakii, cloacae) and two species of Pseudomonas (aeruginosa and putida) were identified. Five Enterobacter isolates were resistant to ampicillin and one isolate was resistant to spectinomycin. All Pseudomonas isolates were multi-resistant (5 to 9 different antibiotics) and resistant to an average of 8.6, 7.9 and 8 antibiotics for CON, CP, and F treatments, respectively. All Pseudomonas isolates were resistant to ampicillin, ceftiofur, florfenicol, sulphachloropyridazine, sulphadimethoxine, and trimethoprim/sulfamethoxazole and most isolates were resistant to chlortetracycline and spectinomycin. No treatment differences were observed in antimicrobial resistance patterns in any of the soil isolates examined. Results reported herein support the use of composted dairy manure as an environmentally friendly soil amendment.