Low serum vitamin D concentrations in Spring-born dairy calves are associated with elevated peripheral leukocytes

Abstract

A role for vitamin D in the immune system is emerging from human research but data in the bovine is limited. In the current study, 48 Holstein–Friesian calves were randomly assigned to one of 4 groups designed to expose calves to divergent vitamin D levels for a 7 month period and to determine its effects on circulating immunity in young calves. Concentrations of circulating 25-hydroxyvitamin D (25OHD) was measured in serum using a commercial ELISA with validated bovine standards. Results showed that mean circulating concentrations of 25OHD at birth was 7.64 ± 3.21 ng/ml indicating vitamin D deficiency. Neither the injection of Vit D3 at birth nor the elevated levels in milk replacer yield discernible changes to pre-weaning circulating concentration of 25OHD. No calf reached the recommended level of vitamin D immune sufficiencyof 30 ng/ml of 25OHD until at least 3 months of age (T4). Increasing dietary Vit D3 via ration in the post-weaning period significantly elevated 25OHD concentrations in serum in VitD-In calves. Maximal levels of circulating 25OHD were achieved in VitD-Out calves, reaching 60.86 ± 7.32 ng/ml at 5 months of age (T7). Greatest divergence in haematology profile was observed between Ctl-In vs VitD-In groups with Ctl-In calves showing an elevated count of neutrophils, eosinophils, and basophils associated with reduced 25OHD concentrations. Neither IL-8 expression nor ROS production in serum were significantly different between calves with high and low 25OHD, indicating that other vitamin D-dependent mechanisms may contribute to the divergent circulating cellular profiles observed. This novel data on the vitamin D status of neonatal calves identifies a significant window of vitamin D insufficiency which is associated with significant differences in circulating immune cell profiles. Vitamin D insufficiency may therefore exacerbate pre-weaning disease susceptibility, and further work in now warranted.

A preliminary analysis of the variation in circulating 25-hydroxycholecalciferol concentrations in peri-partum spring-calving dairy cows

“…In this study, all cows are emerging from a period of housing during the winter months, and therefore reduced exposure to sunlight is likely to be a critical contributor to the low 25(OH)D concentrations detected. This is supported by our recent findings in spring-born Holstein-Friesian dairy calves (Flores-Villalva et al 2021 ).…”

Reduced serum 25(OH)D is closely related to bronchial mucus plug formation in children with mycoplasma pneumonia: A prospective cohort study

“…The absolute values of correlation coefficients of IL-8 and neutrophil percentage were >0.7, which indicated that 25(OH)D was strongly correlated with IL-8 and neutrophil percentage, and weakly correlated with other factors. Flores-Villalva et al (25) found that the number of neutrophils in the experimental group (Spring born calves supplemented with commercial calcium containing pellets) was statistically significant decreased compared with the control group, which was consistent with our results. Some scholars have also shown that vitamin D3 supplementation in healthy people can reduce the serum level of IL-8, and its production was controlled by vitamin D through up-regulating the transcription of the anti-inflammatory gene DUSP1 (double specific phosphatase 1) (26,27).…”

Serum vitamin D3 (25‐OH vit D3) concentrations and hemogram changes in calves with enzootic pneumonia

“…Although there are limited studies in calves, a study conducted in calves with enzootic pneumonia reported that vitamin D concentrations were decreased in diseased animals 4 . What we do know is that vitamin D concentrations are lower in calves from birth until they are 3 months old that serum vitamin D concentrations may not increase despite vitamin supplementation during this early age, and that there is a lack in the development of immunity, making these young animals prone to lung diseases 13 . Accordingly, it has been suggested that serum vitamin D concentrations should be measured in young calves.…”

“…The study animals consisted of a total of 30 Holstein calves, aged 3–5 months, under the same management and feeding conditions. The number of animals used in the study was determined based on previous studies 13,14 . All calves were group‐housed in individual hutches outdoors during the study period and had ad libitum access to calf starter (Emek Feed Company, Turkey) and water.…”

“…The number of animals used in the study was determined based on previous studies. 13,14 All calves were group-housed in individual hutches outdoors during the study period and had ad libitum access to calf starter (Emek Feed Company, Turkey) and water. The starter ingredients were 17% crude protein, 10%-12% crude fiber, 10% crude ash, 0.25% sodium, 2%-3.50% crude fat, 15 000 U/kg vitamin A, 3000 U/kg vitamin D, and 30 mg/kg vitamin E. Calves were fed 3L of pasteurized milk twice a day for 60 days until weaning.…”