ARS | Publication request: Effect of growth promotants on the occurrence of endogenous and synthetic steroid hormones on feedlot soils and in runoff from beef cattle feeding operations

Submitted to: Journal of Environmental Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 3, 2012
Publication Date: January 3, 2012
Citation: Bartelt-Hunt, S.L., Snow, D.D., Kranz, W.L., Mader, T.L., Shapiro, C.A., Van Donk, S.J., Shelton, D.P., Tarkalson, D.D., Zhang, T.C. 2012. Effect of growth promotants on the occurrence of endogenous and synthetic steroid hormones on feedlot soils and in runoff from beef cattle feeding operations. Journal of Environmental Science and Technology. 46:1352-1360.

Interpretive Summary: Supplements and growth promotants (synthetic) containing steroid hormones are routinely administered to beef cattle to improve feeding efficiency, reduce behavioral problems, and enhance production. As a result, beef cattle manure will contain both synthetic steroids as well as a range of endogenous steroids including androgens, estrogens, and progestogens. A two-year controlled study was conducted in which beef cattle were administered steroid hormones via implants and feed additives and the occurrence of sixteen steroid hormones and metabolites was evaluated in runoff from beef cattle feedlots and in manure and soil collected from feedlot surfaces. Synthetic steroids were detected in fresh manure and in feedlot surface soils from cattle administered synthetic steroids. Synthetic steroids were not detected in manure or runoff from cattle not receiving synthetic steroids. A wide range of endogenous hormones (originate from cow, not introduced via supplementation) were detected in runoff and feedlot surface soils and manure from cattle given and not synthetic steroids, with differences in concentration between the two cattle groups. These results indicate that runoff from confined animal production facilities is of environmental and public health concern regardless of the use of growth promotants.

Technical Abstract: Supplements and growth promotants containing steroid hormones are routinely administered to beef cattle to improve feeding efficiency, reduce behavioral problems, and enhance production. As a result, beef cattle manure will contain both synthetic steroids as well as a range of endogenous steroids including androgens, estrogens, and progestogens. A two-year controlled study was conducted in which beef cattle were administered steroid hormones via subcutaneous implants and feed additives and the occurrence of sixteen endogenous and synthetic steroid hormones and metabolites was evaluated in runoff from beef cattle feedlots and in manure and soil collected from feedlot surfaces. Samples were extracted and analyzed using liquid chromatography tandem mass spectrometry for metabolites of the synthetic androgen trenbolone acetate, 17 alpha-trenbolone, 17 beta-trenbolone, for the non-steroidal semi-synthetic estrogen agonist, alpha-zearalanol, and the synthetic progesterone melengesterol acetate, as well as a wide range of endogeneous estrogens, androgens, and fusarium metabolites. Synthetic steroids including trenbolone metabolites and melengestrol acetate were detected in fresh manure and in feedlot surface soils from cattle administered synthetic steroids at concentrations up to 55 plus or minus 22 ng per g dry weight (dw) (17 alpha-trenbolone) and 6.5 plus or minus 0.4 ng per g dw (melengesterol acetate). Melengesterol acetate was detected in 6 percent of runoff samples from feedlots holding cattle administered synthetic steroids at concentrations ranging up to 115 ng per L. The presence of melengesterol acetate in runoff from beef cattle feeding operations has not been previously reported. Synthetic steroids were not detected in manure or runoff from control cattle. A wide range of endogenous 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. These results indicate that runoff from confined animal production facilities is of environmental and public health concern regardless of the use of growth promotants.