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Residues from anabolic preparations after good veterinary practice.
D M Henricks1, S L Gray, J J Owenby
1Department of Animal and Veterinary Sciences, Clemson University, South Carolina 29634-0361, USA. dhnrcks@clemson.edu
Summary
Anabolic implants in steers resulted in tissue estradiol-17beta (E2beta) concentrations below FDA limits. Trenbolone beta (betaTb) levels were also low, indicating safety in edible beef tissues.
Area of Science:
- Veterinary Pharmacology
- Food Science
- Endocrinology
Background:
- Anabolic implants are used to enhance growth in beef cattle.
- Understanding hormone concentrations in edible tissues is crucial for food safety.
- Estradiol-17beta (E2beta) and trenbolone (Tb) are key hormones of interest.
Purpose of the Study:
- To determine endogenous estrogen and trenbolone concentrations in beef cattle tissues.
- To quantify E2beta and trenbolone (betaTb, alphaTb) levels after E2beta and/or trenbolone acetate (TA) ear implants.
Main Methods:
- Validated radioimmunoassays for E2beta, E2alpha, estrone (E1), betaTb, and alphaTb in bovine muscle, liver, kidney, and fat.
- Assays met FDA standards for accuracy, precision, specificity, and sensitivity.
Main Results:
- Endogenous E2beta in steer tissues was <15 ppt; heifer muscle was similar, but liver and kidney were 3-fold higher.
- E2beta implants increased E2beta in steer liver and fat, with levels decreasing by half 24h post-removal.
- After E2beta/TA implants, steer tissues showed E2beta concentrations comparable to or lower than E2beta-only implants, with low betaTb and alphaTb levels.
Conclusions:
- Anabolic implants in steers resulted in tissue E2beta concentrations below the FDA allowable increment.
- Trenbolone beta (betaTb) concentrations were in the lowest quartile (0.25 ppb) 30 days post-implant.
- These findings suggest anabolic implants maintain hormone levels within safe limits in edible beef tissues.