Interrelationship between the indices of copper status in blood and liver of cattle

The relationship between different indices of the copper deficiency was studied in 136 slaughtered male cattle ( 2 years). Copper status has been detected as marginally deficient in 57.4, 36.4, 34.6, and 28.2% of cattle based on the copper concentrations in plasma (5.5-14.5 µmol/L) and liver (19.7-189.1 mg/kgDM), plasma ceruloplasmin levels (85.4 - 178.2 mg/L) and erythrocyte superoxide dismutase (ESOD) activity (2.5-11.4 U/mgHb), respectively. In all cattle, the range of the molybdenum concentrations in plasma (0.1-1.45 µg/mL) was higher than the normal levels; however, in 33.8% of samples the liver molybdenum content (5.0-11.4 mg/kgDM) was higher than the normal range. In 57.7% of cattle with low level of plasma copper concentrations, a low level of ESOD activities (2.5-9.8 U/mgHb) was detected. In 38.3 and 50.0% of cattle with low levels of liver copper (19.7-50.0 mg/kgDM), the plasma ceruloplasmin (85.4-140.3 mg/L) and ESOD (2.5-9.2 U/mgHb) was lower than the normal ranges. In all cattle with low levels of liver and plasma copper and lower levels of plasma ceruloplasmin and EOSD activity, plasma molybdenum concentrations were significantly (P0.0005) higher than to those with normal copper indices. Concurrent low levels of both EOSD activity and plasma cerlupasmin was only observed in 15.7% of cattle. Strikingly, only in 1% of the animals all indices were, simultaneously, lower than normal levels. In 38.5% of cattle with low level of plasma copper and 36.2% with low levels of liver copper, liver molybdenum (2.7-11.4 mg/kgDM) were higher than the normal ranges. In conclusion, complex relationship was observed between biomarkers of copper deficiency and it proved to be difficult to rely on only one index to interpret the copper status. Comparing various indices, it appears that assessment of plasma copper concentration accompanied by ESOD activity could provide a more practical and useful approach in evaluation of copper status in cattle.