Effect of 25-OH-cholecalciferol supplementation on acute phase reactants, cytokines, and colostrum quality of Holstein cows during the transition period and plasma metabolites of newborn calves.

This study investigated the effects of 25-hydroxycholecalciferol (HyD) supplementation on (1) plasma acute phase reactants, cytokines, and Ig concentrations in colostrum in multiparous Holstein cows from 3 wk prepartum to 21 DIM and (2) plasma concentrations of fat-soluble vitamins, Ig concentrations, minerals, and metabolites of newborn calves. Forty-two cows were assigned to receive either cholecalciferol (D3) or HyD. From 21 d before the expected calving until parturition, the D3 group received 0.475 mg/d (0.035 mg/kg DM) of D3, and the HyD group received 1.45 mg/d (0.108 mg/kg DM) of HyD. From parturition until 21 DIM, the D3 group received 0.625 mg/d (0.024 mg/kg DM) of D3, and the HyD group received 0.625 mg/d (0.024 mg/kg DM) of D3 plus 1.0 mg/d of HyD (0.056 mg/kg DM, equal to 0.080 mg/kg of DM in total). Tail blood samples were collected from cows on d -7 (6 ± 2 d), -3 (2 ± 1 d), 0 (13 ± 8 h postcalving), 1 (36 ± 11 h postcalving), 10 (9 ± 2 d), and 20 (16 ± 2 d) relative to calving for plasma analysis of fat-soluble vitamins (A and E), acute phase proteins (haptoglobin [Hap] and serum amyloid A [SAA]), and cytokines (tumor necrosis-α [TNF-α], IFN-γ, and IL-10). Additionally, a blood sample was taken from a jugular vein of the calves 48 ± 3 (mean ± SD) h after birth. For plasma TNF-α concentration in cows, there was an interaction between treatment and time with lower prepartum concentrations in HyD compared with D3; however, the difference was reduced at calving and reached the same level as D3 group at 20 DIM. No treatment effect was observed for plasma Hap, SAA, IFN-γ, or IL-10. Plasma 25-OH-vitamin D3 (25-OH-D3) concentration of newborn calves in HyD group was higher than in calves from D3 group (13.9 and 8.9 pg/mL, respectively), whereas plasma 25-OH-D2, vitamin A, and vitamin E concentrations were unaffected by the treatment. There was a linear relationship between plasma 25-OH-D3 in calves and in their dams. Colostrum IgA, IgM, and IgG concentrations were not affected by treatment. In line with the colostrum results, plasma IgA, IgM, and IgG of calves were not different between D3 and HyD groups. There was no significant difference in plasma Ca and inorganic P concentrations between D3 and HyD groups in newborn calves. In conclusion, HyD supplementation had limited impact on acute phase reactants and cytokines in transition dairy cows. Dietary supplementation of HyD during the close-up period increased plasma 25-OH-D3 concentrations in the newborn calves without affecting plasma Ca and inorganic P. Additionally, the increased plasma 25-OH-D3 concentrations did not affect Ig concentrations in either colostrum or calf plasma.