INTRODUCTION In an attempt to partly explain the increase in non-compliances for prednisolone or prednisone recently occurring in the EU, and particularly in Italy, stressing conditions were tested to clarify the origin of glucucorticoids in cattle urine as these could result from a ’natural’ synthesis starting from cortisol or cortisone, respectively (1). To verify this hypothesis a survey was conducted under field conditions in cows of different breeds reared in different housing systems. MATERIALS AND METHODS The survey was conducted in 131 untreated cows (age range 2.5–8 years) of Piemontese or Friesian breeds, reared in six beef cow-calf enterprises and six dairy farms, respectively, adopting tie-stall barn or littered louse-house systems. Urine sampling was performed under standardized conditions and as recommended by the National Residue Plan. Prednisolone, prednisone, and cortisol urinary levels were measured with a HPLC-MS/MS method (2), with a CCa of 0.66 ng ml)1 for prednisone and of 0.67 ng ml)1 for prednisolone. LOD values were estimated around 0.05 ng ml)1 for both analytes. RESULTS According to the EU legislation in force, none of the 131 examined urine samples could have been officially declared as noncompliant for either analyte. Interestingly, the only cows in which very low prednisolone urinary levels (0.1–0.3 ng ml)1) could be determined were reared under loose housing systems and showed cortisol levels higher than those recorded in negative counterparts bred in tie-stall barns; this was probably due to differences in the response to stressing events like routinely sampling procedures. In our study, measured urinary prednisolone concentrations were remarkably lower than those obtained by Pompa et al. (1) in ACTH-challenged cows and of the same order of magnitude of those detected in finishing bulls administered with prednisolone at a growth-promoting schedule (2). CONCLUSIONS Further research is warranted to ascertain whether the prednisolone/ cortisol urinary ratio could be used to discriminate between the pharmacological use or abuse of the drug and the possible non exogenous origin linked to stressing conditions.
Investigations about the natural occurrence of prednisolone and prednisone in urine samples from cows reared in different housing systems
NEBBIA, Carlo;CARLETTI, Monica;CAPRA, PIERLUIGI;VINCENTI, Marco
2012-01-01
Abstract
INTRODUCTION In an attempt to partly explain the increase in non-compliances for prednisolone or prednisone recently occurring in the EU, and particularly in Italy, stressing conditions were tested to clarify the origin of glucucorticoids in cattle urine as these could result from a ’natural’ synthesis starting from cortisol or cortisone, respectively (1). To verify this hypothesis a survey was conducted under field conditions in cows of different breeds reared in different housing systems. MATERIALS AND METHODS The survey was conducted in 131 untreated cows (age range 2.5–8 years) of Piemontese or Friesian breeds, reared in six beef cow-calf enterprises and six dairy farms, respectively, adopting tie-stall barn or littered louse-house systems. Urine sampling was performed under standardized conditions and as recommended by the National Residue Plan. Prednisolone, prednisone, and cortisol urinary levels were measured with a HPLC-MS/MS method (2), with a CCa of 0.66 ng ml)1 for prednisone and of 0.67 ng ml)1 for prednisolone. LOD values were estimated around 0.05 ng ml)1 for both analytes. RESULTS According to the EU legislation in force, none of the 131 examined urine samples could have been officially declared as noncompliant for either analyte. Interestingly, the only cows in which very low prednisolone urinary levels (0.1–0.3 ng ml)1) could be determined were reared under loose housing systems and showed cortisol levels higher than those recorded in negative counterparts bred in tie-stall barns; this was probably due to differences in the response to stressing events like routinely sampling procedures. In our study, measured urinary prednisolone concentrations were remarkably lower than those obtained by Pompa et al. (1) in ACTH-challenged cows and of the same order of magnitude of those detected in finishing bulls administered with prednisolone at a growth-promoting schedule (2). CONCLUSIONS Further research is warranted to ascertain whether the prednisolone/ cortisol urinary ratio could be used to discriminate between the pharmacological use or abuse of the drug and the possible non exogenous origin linked to stressing conditions.
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