Effects of Parenteral Vitamin D3 Supplementation on Hematological Parameters of Healthy Holstein Bulls.

Vitamin D has been shown to play physiological functions beyond calcium and phosphorus homeostasis and control bone metabolism in the body since its cellular receptors are present in numerous tissues. A total of 20 healthy bulls were divided into four groups to evaluate the effect of different doses of vitamin D3 on the number of bovine blood cells. Groups A, B, C, and D received 11,000, 22,000, 33,000, and 44,000 units/kg of vitamin D3, respectively. The control group was injected with 10 ml of physiological saline intramuscularly. Blood samples were taken before the injection, as well as 2, 4, and 6 days after the injection; furthermore, the white blood cell counts (including granulocytes and lymphocytes), hematocrit, haemoglobin, and platelets were examined by a cell counter. The results showed that vitamin D could cause leukopenia (e.g., neutropenia and lymphopenia), thrombocytopenia, as well as an increase in hematocrit and hemoglobin levels in the blood. Although the mentioned increase or decrease is largely dose- and time-dependent, the first and best group to indicate this is group B. To find the second group, the investigation of the long-term effects of injections, especially in high doses, and evaluation of different tests are required with larger groups over a longer period.