Seasonal variations in the blood concentration of selected heavy metals in sheep and their effects on the biochemical and hematological parameters

- The environmental effect on the health of animals (serum chemistry) was observed.
- Season affected the concentration of heavy metals (lead and copper) significantly.
- Hematological parameters were negatively influenced by heavy metals content.

The main objective of this study was to assess the concentration of various heavy metals (Cd, Pb, Zn, Cu, Hg) in the blood of sheep, followed by biochemical and hematological analysis in order to reveal possible associations. Blood was collected in two different seasons: winter (fed by fodder) and spring (grazing animals). The higher concentrations of Pb (p < 0.01), Cu (p < 0.05) and Hg, but lower of Cd and Zn were found in spring. Evaluation of the biochemical and hematological parameters during different seasons showed a possible environmental effect on the health of animals. A statistically significant increase of Ca (p < 0.001), Mg (p < 0.05), urea (p < 0.001), TP (p < 0.05), glucose (p < 0.01), AST (p < 0.001), ALT (p < 0.001), ALP (p < 0.01), cholesterol (p < 0.001), bilirubin (p < 0.05), triglycerides (p < 0.001) and a decrease of P (p < 0.05), HGB (p < 0.05), MCHC (p < 0.05) and RDWc (p < 0.05) in spring was detected. The results of this study showed statistically significant correlations between Pb and ALP (r = 0.53) level in winter and between Pb and Ca (r = −0.73) in the spring. The hematological analysis revealed a significant correlation between Zn and RBC (r = 0.61), MCV (r = −0.74), MCH (r = −0.71) and between Pb and MCH (r = −0.55), PCT (r = −0.66), PDWC (r = −0.55) in the winter. A high positive significant correlations were found between Cd and RDWC (r = 0.77) and Cu and RDWC (r = 0.75). The significance of this work is the use the data in the preventive diagnosis of metabolic and production diseases. The collected data may serve as a control indicator to detect toxic hazards related to the heavy metal occurrence on animal health status.