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) an d Synovex-H (R) (200 mg testosterone propionate plus 20 mg estradiol bcnzoa te) in heifers (1-fold, 3-fold and 10-fold dose), and 2) non-approved treat ment of female veal calves (1-fold dose of Synovex-H (R) or Synovex Plus (R ) with 200 mg trenbolone acetate plus 28 mg estradiol benzoate). Residues o f estradiol-17 beta, estradiol-17 alpha, estrone and testosterone, trenbulo ne-17 beta, trenbolone-17 alpha and trendione or zeranol, respectively, wer e measured in loin, liver, kidney and peri-renal fat by high performance li quid chromatography/enzyme immunoassay (WPLC/EIA) after liquid-liquid extra ction and solid-phase clean-up. The hormone residues in the multiple-dose e xperiments were dose-dependent and partially exceeded the threshold values: in the liver in one animal after 3-fold dose and in two animals after 10-f old dose 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 be low those of heifers and did not infringe threshold values.