Broiler Litter Stacking Reduces Hormone Concentrations.

Poultry litter contains the naturally-excreted sex hormones testosterone and estradiol, which may contaminate surface runoff following litter application to grasslands.  Therefore, there is a need to identify management practices that reduce hormone concentrations in the litter before land application.  Although composting poultry litter has been shown to reduce hormone concentrations,  most poultry producers do not compost their litter but stack it in stack houses for a few to several weeks before field application.  The objective of this study was to evaluate the effect of poultry litter stacking on concentrations of testosterone, estradiol, and estrone.  Two stack houses were sampled in 30-cm increments immediately after poultry litter stacking to a depth of 120 cm and four weeks later.  Samples were freeze dried, ground, and extracted for analysis of testosterone, estradiol and estrone by GC/MS.  Temperature in the stack house was monitored with dataloggers at the center of 30-cm increments, and litter water content was measured in initial and final samples.  Temperatures rose immediately after litter stacking and reached maximum values of 60 to 70 C within three to seven days. Litter water content decreased during stacking.  Concentrations of testosterone, estradiol, and estrone were reduced by as much as 50% during  four weeks of stacking.  These results indicate that litter stacking is a management practice that may help reduce the concentrations of sex hormones in poultry litter before land application.