Effects of parenteral over-supplementation of vitamin A and iron on hematology, iron biochemistry, weight gain, and health of neonatal dairy calves.

Forty Holstein calves were used for the experiment and randomly assigned to four different treatments. Treatments consisted of control (injections of 5 ml normal saline), test 1 (500 mg Fe injected to each calf at 24-48 h of age), test 2 (200,000 IU vitamin A was injected to each calf at 24-48 h of age), and test 3 (Fe and vitamin A were injected to each calf as mentioned previously. Group had significant effect on the amounts of HCT, RBC, hemoglobin, MCH, platelets, iron concentration and total iron binding capacity (TIBC) saturation (p<0.05). These parameters were significantly higher in test 1 for RBC parameters, test 1 and test 3 for iron concentration and test 1 for TIBC saturation in comparing to control group. Age (sampling time) had significant effects on the values of most measured parameters (p<0.05) except MCHC, WBC, TIBC, and TIBC saturation. Significant interactions between sampling time and group were seen for HCT, RBC number, hemoglobin concentration, and MCV. No significant differences were seen for total weight gain, and mean daily weight gain between groups. Chi-square test revealed no significant difference for the percent of days of treatment between trial groups.