ABSTRACT
In an effort to improve the efficiency of livestock production, producers have become reliant on the use of chemical growth promoting agents. Growth promoting drugs include antibacterial feed additives, antibiotic ionophores, and anabolic hormones. These drugs are usually available for over the counter purchase and are administered by the livestock producer at specific stages in the production cycle. Hormonal growth promoting agents are approved in the United States for use only in beef cattle and sheep. Steroid hormones are synthesized from cholesterol in the gonads, adrenal cortex, and placenta. In ruminants, testosterone is metabolized to epistosterone whereas the major metabolites produced by nonruminants include androsterone, etiocholanolone, and dehydroepiandrosterone. Trenbolone acetate is a synthetic androgenic hormone which has recently been approved for use in cattle in the United States. Dexamethasone is a long-acting synthetic glucocorticoid approved for use in cattle as an antiinflammatory or gluconeogenic agent.
