STABILITY OF ZERANOL, NANDROLONE AND TRENBOLONE IN BOVINE URINE

The stability of some growth promoting agents in cattle urine, under v arious temperature storing conditions, was investigated. Bovine urine samples obtained from previous excretion studies which contained zeran ol, nandrolone and trenbolone respectively, were stored frozen, at roo m temperature and in direct sunlight. On days 0, 2, 4, 7 and 10, zeran ol and nandrolone were quantified by selective ion monitoring analysis on a gas chromatography-mass selective detector and trenbolone by usi ng an enzyme linked immunosorbent assay. Zeranol and its metabolite ta leranol are stable under all of these storage conditions. There is a r emarkable decrease in the concentration of 17 alpha-19-nortestosterone , the main metabolite of nandrolone in cattle, when stored at room tem perature and in direct sunlight. There is also a decrease in concentra tion of trenbolone when stored in direct sunlight. From the results it can be concluded that urine specimens obtained from cattle for residu e analysis should be frozen as soon as possible after collection.