Supplementation of vitamin E, selenium and increased energy allowance mitigates the transition stress and improves postpartum reproductive performance in the crossbred cow

•Increasing dietary energy along with Vitamin E and Se supplementation mitigated the oxidative stress in the crossbred cow.•Increasing dietary energy along with Vitamin E and Se supplementation improved the immune function.•Increasing dietary energy along with Vitamin E and Se supplementation improved the postpartum reproductive performance.

Dairy cow undergoes tremendous physiological challenges during the transition period leading to negative energy balance (NEBAL), impaired immunity and oxidative stress that ultimately compromises the postpartum fertility. Accordingly, we investigated the effects of antioxidant supplementation and increased energy allowance on transition stress and fertility of crossbred cow. Advanced pregnant crossbred cows (n = 26) of 2-4 parity and lactation potential of >10 L/day were divided into two equal groups (n = 13 cows/group). Cows were fed diets either (i) supplemented with vitamin E (80 IU/kg DM), Selenium (Se; 0.3 mg/kg DM) and increased energy allowance in the form of 20% additional concentrate (TRT) or (ii) basal diet without any supplementation as control (CON). Vitamin E and Se were supplemented with wheat flour bolus from −4 to 8 week of calving whereas energy allowance was increased from 2 to 8 week of calving on daily basis to individual animal (where 0 is day of calving). Blood samples were collected on weekly interval from −4 to 8 week of calving. Oxidative stress was assessed by estimation of malondialdehyde (MDA), total antioxidant capacity (TAC), superoxide dismutase (SOD) and catalase (CAT). Immunity level was assessed via estimation of phagocytic activity (PA) of granulocytes and lymphocyte proliferation assay (LPA). Postpartum fertility was assessed by interval to first postpartum estrus (day) and pregnancy rate. Cows in TRT had a significantly lower MDA, higher TAC and decreased activity of SOD and CAT than that of CON (P < 0.05). Phagocytic activity increased at −1, 0 and 3-8 weeks postpartum (P < 0.05) while LPA showed difference (P < 0.05) at parturition, week 4 and 8 postpartum. Marked improvement in the fertility was recorded in terms of early resumption of postpartum estrus (P < 0.001) and higher pregnancy rate (P < 0.05).