Vol. 10, Issue 10, Part G (2025)

The transition period (three weeks prepartum to three weeks postpartum) in dairy cattle is marked by metabolic stress, oxidative imbalance, and alterations in mineral and hematological parameters. The present study evaluated hematobiochemical changes in oxidative stress-affected crossbred dairy cows and assessed the effect of Vitamin E and selenium supplementation. Thirty animals were divided into three groups: Group I (normal control), Group II (oxidative stress-affected, untreated), and Group III (oxidative stress-affected, treated with Vitamin E + selenium). Blood samples were analyzed for calcium, phosphorus, magnesium, and hematological indices including hemoglobin (Hb), packed cell volume (PCV), total erythrocyte count (TEC), total leukocyte count (TLC), and differential leukocyte count (DLC).
Serum calcium (mg/dL, mean ± SD) at three weeks prepartum was 10.0±0.87 (control), 7.04±0.57 (untreated), and 7.63±1.01 (treated), with postpartum levels of 9.71±0.6, 7.42±0.3, and 8.44±0.48, respectively. Calcium decreased significantly (p?0.05) in untreated animals, while treatment improved levels near normal. Magnesium (2.5±0.27 to 2.46±0.34 mg/dL in controls) and phosphorus (6.44±0.82 to 6.71±0.52 mg/dL) remained stable across groups.
Hematological indices remained largely within physiological limits. Mean Hb ranged from 8.93±1.25 to 9.03±0.82 g/dL, PCV from 27.8±2.94% to 28.4±2.17%, and TEC from 5.4±0.32 × 10?/µL to 5.62±0.20 × 10?/µL in controls, showing minimal variation. TLC values were higher in oxidative stress groups (9570±1322 cells/µL in untreated vs. 8210±647 cells/µL in control), indicating immune activation. Lymphocytes increased significantly in the treated group postpartum (72.4±2.76%) compared with controls (65.3±1.83%), while neutrophils were elevated in untreated cows (29.7±2.26%) suggestive of inflammation.
In conclusion, oxidative stress significantly lowered calcium and altered leukocyte dynamics during the transition period. Vitamin E and selenium supplementation improved calcium homeostasis, maintained erythrocyte integrity, and enhanced lymphocyte response, highlighting their efficacy in mitigating oxidative and metabolic stress in dairy cattle.