Environmental and genetic factors influence the vitamin D content of cows’ milk

Summary

This narrative review synthesises evidence on the environmental and genetic drivers of vitamin D concentration in dairy milk. The authors demonstrate that cattle vitamin D status—determined by dietary intake, sunlight exposure via UVB, and genetic breed factors—directly influences milk vitamin D content, with clear seasonal patterns documented. The review highlights that intensive year-round housing practices reduce solar exposure and suppress milk vitamin D, whilst traditional grazing systems maintain higher concentrations, and identifies breed variation and dietary intervention as additional levers for nutritional modification.

Regional applicability

This study is United Kingdom-based and directly relevant to UK dairy farming policy and practice. The findings have immediate applicability to UK systems where there is growing interest in pasture-based and seasonal dairy production, and where year-round indoor housing is increasingly common; the evidence supports potential for UK farmers to enhance milk micronutrient density through husbandry and breeding choices.

Key measures

Vitamin D concentration in milk; seasonal variation; influence of housing practices, UVB exposure, dietary vitamin D sources, and cattle breed on milk vitamin D content

Outcomes reported

The review examined how environmental factors (housing, sunlight exposure, diet) and genetic factors (breed) influence vitamin D concentration in milk produced by dairy cattle. It identified seasonal variation and the potential for farmer practices to modify milk vitamin D content.

Topic tags