Detection of anabolic residues in misplaced implantation sites in cattle

Eight weeks before slaughter, 26 heifers, 2 calves, and 1 steer were implanted with licensed anabolic preparations at off-label injection sites. After slaughter, 24 of 31 implantation sites (77%) were detected. Residual pellets of Revalor H contained a mean of 42.9 mg trenbolone acetate (range 19.8-57.7 mg) and 4.6 mg (1.96-6.45 mg) estradiol, corresponding to 30% (19.8-57.7%) and 32.7% (14.0-46.6%) of the originally applied dose, respectively. In the tissue areas containing residual Revalor H pellets, total residues ranged from 14.8 microg to 12.6 mg trenbolone acetate, 41.7 microg to 1.45 mg trenbolone, and 11.1 microg to 3.39 mg estradiol. The outer tissue areas of the injection sites contained <2 microg hormones. The preparations Synovex H, Finaplix H, Implus S, and Component EC behaved similarly to Revalor H. Residues of Synovex Plus were low, whereas the Compudose silicone rubber contained 58.8% of the implanted dose, but left no significant tissue residues. If implantation sites are processed in meat manufacturing, international threshold levels of the respective substances will be exceeded in tons of meat products.