Presence of Mycophenolic Acid, Roquefortine C, Citrinin and Ochratoxin A in Maize and Grass Silages Supplied to Dairy Cattle in Belgium

The dietary exposure of cattle to roquefortine C (ROC), mycophenolic acid (MPA), citrinin (CIT) and ochratoxin A (OTA) has been quantified under practical farming conditions, considering mouldy and non-mouldy maize and grass silages collected in Belgium. Mean ROC load was significantly higher (p=0.015) in mouldy maize silages (1,848 µg/kg) than in non-mouldy counterparts (459 µg/kg). As for grass silages, no significant difference was observed for these two subsamples (852 µg/kg in mouldy against 319 µg/kg in the non-mouldy side). Regarding MPA concentrations, no significant difference exists between mouldy and non-mouldy samples, neither for maize (4,448 µg/kg versus 6,323 µg/kg) nor for grass silages (3,587 µg/kg versus 1,268 µg/kg). A significant association (r=+0.226, p<0.05) was derived between CIT and OTA contents in maize and grass silages showing that these toxins co-occurred. The absence of visible moulds does not guarantee the mycotoxin free feedstuffs. Care should be taken to avoid the carry-over of these mycotoxins to the milk, meat or edible offal. We therefore recommend developing tools for early detecting the mycotoxin in these foodstuffs and by paying more attention to the ensiling processes in Belgium.