Presence of prednisolone in complementary feedstuffs for bovine husbandry

BACKGROUND: According to European Union legislation, prednisolone, a steroid that belongs to the glucocorticosteroid group, is banned as a growth promoter in cattle husbandry and therefore should not be present in bovine feedstuffs. As our preliminary investigations detected prednisolone in this matrix, we performed a study on different commercially available complementary feedstuffs, stored at the farm and/or in the laboratory, in order to verify whether its presence was due to neo-formation during storage. RESULTS: Prednisolonewas detected in almost all (95%) feedstuffs collected at the farm.When the feedstuffswere stored at the laboratory, the frequency (31%) and the concentration of prednisolone-positiveswere lower. This difference, which is likely due to different environmental conditions, implies the possibility of its neo-formation. CONCLUSION: Our data indicate that the neo-formation of prednisolone can occur in feedstuff, and that the frequency and concentration could be related to the storage conditions. The individuation of an objective parameter that is useful for the identification of the compliance of feed is therefore essential.