Hormone contents in peripheral tissues after correct and off-label use of growth promoting hormones in cattle: effect of the implant preparations Filaplix-H, Raglo, Synovex-H and Synovex Plus.

Abstract

Certain hormonal growth promoters are licensed in several beef producing countries outside the European Union (EU). Use in compliance with Good Veterinary Practice is mandatory. As risk assessment of hormone residues in animal tissues up to now has neglected potential off-label use, the present study dealt with two topics: 1) multiple treatment with the implant preparations Finaplix-H (200 mg trenbolone acetate), Ralgro (36 mg zeranol) and Synovex-H (200 mg testosterone propionate plus 20 mg estradiol benzoate) in heifers (1-fold, 3-fold and 10-fold dose), and 2) non-approved treatment of female veal calves (1-fold dose of Synovex-H or Synovex Plus with 200 mg trenbolone acetate plus 28 mg estradiol benzoate). Residues of estradiol-17beta, estradiol-17alpha, estrone and testosterone, trenbolone-17beta, trenbolone-17alpha and trendione or zeranol, respectively, were measured 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 experiments 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-fold dose of Finaplix-H, and in the liver and kidney after 3-fold and 10-fold dose of Synovex-H. Mean hormone residues in calves were mainly below those of heifers and did not infringe threshold values.