Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/18/2008
Publication Date: 8/18/2008
Citation: Arikan, O., Mulbry III, W.W., Rice, C. 2008. Reduction of Chlortetracycline Residues in Manure from Therapeutically-Treated Beef Calves. Meeting Abstract. Interpretive Summary: .
Technical Abstract: Chlortetracycline (CTC) is one of only ten antibiotics licensed in the U.S.A. for use as growth promoters for livestock. The objective of this study was to determine the effect of composting on the fate of CTC residues found in manure from CTC-medicated beef calves. Five animals were medicated for 5 days with 22 mg/kg/day of CTC. Manure samples collected prior to and after medication were mixed with straw and woodchips, and portions of these mixtures were treated in laboratory composters for 30 days. In addition, aliquots of the CTC-containing mixture were incubated at 25 oC or sterilized followed by incubation at 25 oC and 55 oC (composting temperature). The presence of CTC did not appear to affect the composting process. Our results using sterile and non-sterile samples suggest that the decrease in concentrations of extractable CTC and its epimer at 25 oC and 55 oC is due to abiotic processes.