High sensitivity of a histological method in the detection of low-dosage illicit treatment with 17β-estradiol in male calves

With this study we evaluated the performance of a histological method for the detection of microscopic lesions in the sexual accessory glands of veal calves administered 17β-estradiol valerate for growth promotion; our goal was to determine whether the method might hold potential as an official screening technique according to the Commission Decision 2002/657/EC. The target organs of veal calves treated with low-dose 17β-estradiol valerate and those of control animals were microscopically examined in blinded manner and the histolopathogical features scored by two pathologists. Distinct histopathological differences were seen in the prostate and the bulbo-urethral glands of the treated animals versus the controls. Our findings indicate that, compared with the negative results obtained with the official test, this histopathological method can identify illicit 17β-estradiol valerate treatment up to 15 days after the last drug administration. Based on the preliminary evidence for the method’s high specificity and sensitivity, a validation study could be set up according to Decision 2002/657/EC. Confirmation of its performance could support adoption of histopathology as an official screening method in the National Residue Monitoring Program for the detection of illicit estrogenic treatment