Age and sex dependent side effects of Tilmicosin on cardiac enzymes and hematological parameters in calves

Tilmicosin is a macrolide antibiotic that is used mainly in veterinary medicine. Increased dose of tilmicosin lead to fatal cardiotoxic effects in humans. However, dose, age and sex dependent effect of tilmicosin in ani-mals has not been identified yet. Therefore, we compared the side effect of two subcutaneous injection doses of tilmicosin on both cardiac enzymes (as indices of cardiac toxicity), and hematological parameters in calves among both sexes receiving at age of 6 and 12 months with that of control group. twenty-four calves were divided into eight groups (3 calves/each); two groups of 6-month male, two groups of 6 month female, two groups of 12 month male, two groups of 12 month female (each group receive twice subcutaneous doses “at day 1 and 4 of experiment” of either saline “control group” or tilmicosin “treated group”). Serum and blood were collected for both biochemical and hematological analysis among studied groups. In com-parison to the control groups, the treated groups specially in female revealed significant increase of serum LDH and CK-MB (cardiac injury indicators), and granulocyte count, with significant decrease in the HCT, WBC, RBCs count. However, no significant difference among treated and control groups for the values of MID, MCV, HGB, lymphocytes and platelets count. Increased dose of tilmicosin could induce some side effects on hematological and biochemical parameters in calves and our study suggests sex differences in this effect.