Metabolites in feces can be important markers for the abuse of anabolic steroids in cattle

In Belgium to control the abuse of anabolic steroids in cattle, urine sampl es have been gradually replaced by feces samples, because the latter can be obtained more easily from living animals. Urine and feces samples were col lected from heifers after administration of boldenone, norethandrolone or e thylestrenol. Metabolites present in feces or urine were determined by GC-M S. Large qualitative and quantitative differences in the metabolic profiles were observed. In feces, in contrast to urine, the parent compounds or the ir major metabolites were detectable only shortly after administration. On the other hand, metabolites resulting from the reduction of the 3-oxo group and the unsaturated carbon-carbon bonds, present on the A-ring, allow for long-term detection in feces. A-ring reduced metabolites have been identifi ed in samples found positive for norgestrel, boldenone, methylboldenone and methyltestosterone, respectively. These results are in agreement with conc omitant in vivo experiments.