Illicit use of dexamethasone in meat cattle: rationale, effects on treated animals, and traditional and innovative diagnostic techniques

The illegal use of synthetic corticosteroids (especially dexamethasone) for growth-promoting purposes is a relatively common practice in meat cattle breeding. These drugs, administered alone or in combination with other substances (i.e. steroid hormones and beta-agonists), are able to improve the productive performances of animals with several advantages for the farmers. Since the residues of glucocorticoids in the foodstuffs are dangerous for human health, very low Maximum Residue Limits in the bovine edible tissues have been set. However, the current strategies of illicit treatments are based on the application of low dosages and routes of administration (e.g. the oral one) that help in eluding the official controls performed according to the National Residue Monitoring Plans. The aim of this review is to describe the chemical and pharmacological characteristics of synthetic corticosteroids that give reason for their illicit use, and to illustrate the conventional diagnostic techniques employed to reveal their misuse in meat cattle breeding. Moreover, some new methodologies, recently developed to support the traditional analysis, will be discussed.