Hormone contents in peripheral tissues after correct and off-label use of growth promoting hormones in cattle: Effect of the implant preparations Finaplix-H (R), Ralgro (R), Synovex-H (R) and Synovex Plus (R)

Certain hormonal growth promoters are licensed in several beef producing co untries outside the European Union (EU). Use in compliance with Good Veteri nary Practice is mandatory. As risk assessment of hormone residues in anima l tissues up to now has neglected potential off-label use, the present stud y dealt with two topics: 1) multiple treatment with the implant preparation s Finaplix-H(R) (200 mg trenbolone acetate), Ralgro(R) (36 mg zeranol) and Synovex-H(R) (200 mg testosterone propionate plus 20 mg estradiol benzoate) in heifers (1-fold, 3-fold and 10-fold dose), and 2) non-approved treatmen t of female veal calves (1-fold dose of Synovex-H(R) or Synovex Plus(R) wit h 200 mg trenbolone acetate plus 28 mg estradiol benzoate). Residues of est radiol-17 beta, estradiol-17 alpha, estrone and testosterone, trenbolone-17 beta, trenbolone-17 alpha and trendione or zeranol, respectively, were mea sured in loin, liver, kidney and peri-renal fat by high performance liquid chromatography/enzyme immunoassay (HPLC/EIA) after liquid-liquid extraction and solid-phase clean-up. The hormone residues in the multiple-dose experi ments were dose-dependent and partially exceeded the threshold values: in t he liver in one animal after 3-fold dose and in two animals after 10-fold d ose of Finaplix-H(R), and in the liver and kidney after 3-fold and 10-fold dose of Synovex-H(R), Mean hormone residues in calves were mainly below tho se of heifers and did not infringe threshold values.