Epidemiology of trace elements deficiencies in Belgian beef and dairy cattle herds.

Selenium (Se), iodine (I), zinc (Zn) and copper (Cu) deficiencies in cattle have been reported in Europe. These deficiencies are often associated with diseases. The aim of the study was to assess trace element status in Belgian cattle herds showing pathologies and to compare them to healthy cattle herds. Eighty-two beef herds with pathologies, 11 healthy beef herds, 65 dairy herds with pathologies and 20 healthy dairy herds were studied during barn period. Blood and/or milk samples were taken in healthy animals. Plasma Zn, Cu, inorganic I (PII) and activity of glutathione peroxidase in erythrocytes (GPX) were assayed. In milk, I concentration was measured. Data about pathologies and nutrition in the herds were collected. According to defined thresholds, it appeared that a large proportion of deficient herds belonged to "sick" group of herds. This conclusion was supported by the mean value of trace elements and by the fact that a majority of individual values of trace elements was below the threshold. Dairy herds had mean values of trace elements higher than beef herds. More concentrates and minerals were used in healthy herds versus "sick" herds. These feed supplements were also used more often in dairy herds, compared to beef herds. Trace elements deficiencies are present in cattle herds in Belgium and are linked to diseases. Nutrition plays a major role in the trace elements status.