The effects of seasonal variations on concentrations of some minerals in serum of cattle

SUMMARYThe aim of this study was to investigate the possible effects of seasonal variations onthe calcium, phosphorus, magnesium, zinc, copper, and iron concentrations in cattle. Serumsamples were collected four times a year at each season: May, August, November andFebruary.In spring, summer, autumn and winter seasons, the average serum calciumconcentrations were respectively 1,79 mmol/l, 2,14 mmol/l, 2,25 mmol/l and 2,32 mmol/l; theaverage serum phosphorus concentrations were respectively 1,72 mmol/l, 1,04 mmol/l, 1,66mmol/l and 1,55 mmol/l; the average serum magnesium concentrations were respectively 0,99mmol/l, 1,11 mmol/l, 1,72 mmol/l and 0,91 mmol/l; the average serum zinc concentrationswere respectively 16,090 µmol/l, 14,59 µmol/l, 16,98 µmol/l and 8,39 µmol/l; the averageserum copper concentrations were respectively 10,51 µmol/l, 13,82 µmol/l, 9,04 µmol/l ve29,81 µmol/l; the average serum iron concentrations were respectively 24,64 µmol/l, 18,58µmol/l, 23,02 µmol/l ve 19,80 µmol/l.Serum calcium concentrations in spring and serum phosphorus concentrations insummer were found lower than other seasons (p<0,001). Magnesium and iron concentrationsin serum varied with seasonal variations (p<0,001). Mean copper concentrations in winterwere detected higher than spring, summer and autumn. On the other hand, serum zincconcentrations in winter were found lower than other seasons. These differences werestatistically significant.We suggest that seasonal and physiologic variations must be taken into considerationfor the correct inter pretation of serum elemental status in cattle. We recommend that samplesbe taken from various species of animals at different times of the year and in differentphysiologic statues so that proper reference values are obtained.