Effects of feeding different doses of 25-hydroxyvitamin D3 on the growth performance, blood minerals, antioxidant status and immunoglobulin of preweaning calves

Abstract

The objective of this trial was to investigate the effects of feeding different doses of 25-hydroxyvitamin D3 (25(OH)D3) on the growth performance, blood minerals, vitamin D3 metabolites, antioxidant capacity and immunoglobulin of pre-weaned calves. In this experiment, eighteen Holstein calves (3.5 ± 1.24 days, average body weight: 40.68 ± 1.21 kg) were randomly assigned to 1 of 3 treatments (6 calves per group): the control group (0 IU 25(OH)D3 per calf per day), low-dose group (6000 IU 25(OH)D3 per calf per day) and high-dose group (12,000 IU 25(OH)D3 per calf per day). The 25(OH)D3 was mixed into the milk and offered to the calves. Calves fed 25(OH)D3 showed a linear increase in ADG (P = 0.013) and feed efficiency (P = 0.039) from 1 to 8 weeks, the withers height showed an improvement (P < 0.05) at 56 d. The plasma total calcium level tended to increase (P = 0.074) at 28 d and linearly increased (P = 0.012) at 56 d, and plasma 25(OH)D3 in calves linearly increased (P < 0.001) by feeding 25(OH)D3. The plasma total phosphorus content linearly increased (P = 0.003) at 56 d, but there was no difference in plasma total magnesium content by increasing feeding 25(OH)D3. Plasma growth hormone (P = 0.276) and insulin-like growth factor Ⅰ (P = 0.117) were not affected by treatment at 28 d, but growth hormone tended to increase (P = 0.058) and insulin-like growth factor Ⅰ linearly increased (P = 0.018) by increasing feeding 25(OH)D3 at 56 d. Plasma catalase (P < 0.05) and superoxide dismutase (P = 0.010) contents linearly increased by increasing feeding 25(OH)D3. Additionally, increasing 25(OH)D3 supplementation linearly increased (P < 0.05) the plasma immunoglobulin G concentration. In conclusion, the results indicated that feeding 25(OH)D3 (especially high dose of 25(OH)D3) could effectively improve growth performance, plasma minerals and hormones concentration and enhance the antioxidant capacity and immunoglobulin of calves. Feeding 25(OH)D3 is expected to be an effective means of promoting growth and maintaining the health of calves before weaning.