CONTROL OF THE ILLEGAL ADMINISTRATION OF NATURAL STEROID-HORMONES IN URINE AND TISSUES OF VEAL CALVES AND IN PLASMA OF BULLS

In the context of the control of the illegal administration of natural steroid hormones in cattle husbandry, decision levels of sex steroid hormones were established, taking into account the effect of the treatment, for the cases of the urine of male and female veal calves treated with estradiol and/or testosterone-containing implants, and the plasma of bulls treated by an injection of an estradiol-testosterone cocktail. At each decision level, a score was assigned, that represents the percentage of treated animals detected when the decision limit is applied. Concerning the veal calves, a maximum decision level is proposed for the 17beta-estradiol in urine of 1 ng ml-1 in both male and female veal calves, giving a score of 95%. A minimum decision level was set at 2 ng ml-1 for testosterone in urine of male veal calves, with a score of 95% (95% of the implanted male veal calves display a urinary testosterone level lower than 2 ng ml-1). For female veal calves, a maximum decision level was set at 0.45 ng ml-1 for the urinary testosterone concentration (score of 90%). For bulls, the 17beta-estradiol concentration in plasma is a good criterion for detecting injected bulls: a maximum decision level was set at 40 pg ml-1, displaying a score ranging from 100 to 45%, 2 and 7 days after the injection, respectively.