Effects of short-term over-supplementation of copper in milk on hematology, serum proteins, weight gain, and health in dairy calves.

Thirty-six calves were used in the present study. The animals were divided equally into three groups (control, test 1, and test 2). The three groups of calves were homogeneous for parity of dams, sex, and month of birth. From 14 days of age, in the test 1 group copper as copper sulfate (Merck Co, Germany) was added to each meal of milk at a rate of 10 mg/kg of milk for 14 days and in test 2 group copper as copper sulfate was added to each meal of milk at a rate of 20 mg/kg of milk for 14 days. Blood samples were taken by jugular venipuncture using disposable syringes at 14 (before Cu supplementation), 30, 60, and 80 days of age. Anticoagulated blood was used for CBC determination. Plane tubes were used for harvesting of serum and the amounts of total serum protein, albumin, iron, and copper were measured. Calves were weighted at birth and at the end of trial (day 80) and total gain and mean daily gain were calculated. Days of treatment for ill calves were also recorded during experiment. Group (treatment) had no significant effect on the amounts of measured parameters except MCH values (p < 0.05) which were significantly lower in test 1 group than other trial groups. Age (sampling time) had significant effects on the values of most measured parameters (p < 0.05) except WBC, lymphocyte, total protein, and fibrinogen. Significant interactions between sampling time and group were not seen for any of measured parameters. No significant differences were seen for total weight gain and mean daily gain between trial groups. Chi-square test revealed no significant difference for the days of treatment between trials groups.