Occurrence of ectoparasiticides in Australian beef cattle feedlot wastes

► A method by LC-MS/MS was developed for a small scale survey of 6 ectoparasiticides in cattle feedlot wastes. ► Pyrethroids were not detected in feedlot samples. ► Macrocyclic lactones were detected in the concentration range 1-36 μg/kg d.w. ► Concentrations varied and were dependent on type of sample.