Supplementation of antioxidant micronutrients reduces stress and improves immune function/response in periparturient dairy cows and their calves.

BACKGROUND: Periparturient period induces stress in cows which fluctuates hormonal and metabolic function and causes immune suppression. Apart from impairing the health, production, and reproduction of cows, it also influences the well-being of newborn calves by decreasing the colostrum quality. Micronutrients are known for optimal health and production and their effects on parturition stress, immune response in both cow and its calf need to be explored. AIM: The aim of this study was to see the effect of oral supplementation of micronutrients during the prepartum period on the health status of crossbred dairy cows and subsequently on their newborn calves. METHODS: A total of 42 healthy multiparous cows were selected and randomly divided into five groups with seven cows in each group, i.e. control (Basal Diet, BD), VA group (BD + vitamin A, 105 IU), Zn group (BD + zinc sulphate, 60 ppm), VE group (BD + vitamin E, 2500 IU), and combined supplementation (CS) group (BD + combination of VA, Zn, and VE). The supplements were offered in compounded concentrate DM (100 g) to individual cows once daily before the morning feeding and the remaining portion was incorporated in the TMR. Feeding was started one month before the expected days of calving till calving. Blood samples were collected from cows at days -15, -7, -3, 0, +3, +7, and +15 relative to the day of calving. Blood samples from newborn calves and milk samples of cows were collected at days 0, +3, +7, and +15. Milk somatic cell counts (SCC) were estimated using a cell counter. Cortisol was estimated by ELISA kit in blood and milk plasma of cows and in the blood plasma of their calves. Total immunoglobulins (Ig) were estimated in milk of cows and serum of calves using zinc sulphate turbidity method. Blood neutrophils from cows and calves were studied for phagocytic activity (PA) using nitro blue tetrazolium (NBT) assay.Data were analysed by repeated-measures two-way ANOVA using the mixed procedure of SAS, and the pairwise comparison was performed using a multiple comparison test (Tukey). RESULTS: Combined supplementation of micronutrients decreased (P < 0.05) maternal blood plasma (control vs. CS group, 5.98 ±â€¯0.20 vs. 3.86 ±â€¯0.23 ng/mL) and milk plasma (3.96 ±â€¯0.13 vs. 2.71 ±â€¯0.10 ng/mL) cortisol, milk SCC (3.05 ±â€¯0.11 vs. 2.12 ±â€¯0.10 × 105 cells/mL) and increased (P < 0.05) total milk Ig concentration (18.80 ±â€¯0.11 vs. 23.04 ±â€¯0.57 mg/mL) and the PA of blood neutrophils (0.84 ±â€¯0.03 vs. 1.07 ±â€¯0.03). Similarly, lower blood cortisol concentration (9.69 ±â€¯0.35 vs. 6.02 ±â€¯0.18 ng/mL) and higher (P < 0.05) total Ig (23.26 ±â€¯0.11 vs. 30.34 ±â€¯0.70 mg/mL) and PA of blood neutrophils (0.37 ±â€¯0.02 vs. 0.52 ±â€¯0.02) were observed in the calves born to CS group of cows as compared to the control. Highest (P < 0.05) positive effects (lower stress levels and higher immune response) of treatment were noticed in CS group followed by VE group and then Zn group. However, VA group didn't differ from the control group. CONCLUSION: Our results indicate that micronutrient interventions during the prepartum period can improve the health status of dairy calves and subsequently the well-being of their calves.