Growth promotants containing steroid hormones are routinely administered to beef cattle to improve feeding efficiency, reduce behavioral problems, and enhance production. In this study, beef cattle were administered growth promotants and the occurrence of sixteen natural and synthetic steroid hormones and metabolites was evaluated in runoff, manure and soil collected from feedlot surfaces. Synthetic steroids including trenbolone metabolites and melengestrol acetate were detected in fresh manure and in feedlot surface soils at concentrations up to 55�22 ng/g and 31�6 ng/g, respectively.  Melengesterol acetate was detected in 6% of runoff samples from feedlots holding cattle administered synthetic steroids at concentrations ranging up to 115 ng/L. Natural hormones were detected in runoff and feedlot surface soils and manure from cattle given synthetic steroids and from control cattle, with no statistically significant differences in concentration.  Synthetic steroids were predominantly associated with manure solids and soils, and may be introduced to the environment after land application of manure.

Occurrence of natural and synthetic steroid hormones on feedlot soils and in runoff from beef cattle feeding operations using growth promotants

243rd National Meeting (2012)

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