Both cow and goat milk are both naturally quite low in Vitamin D unless fortified.

Cow’s milk is one of the core dairy foods that the Australian Dietary Guidelines recommend you enjoy every day.¹ Some people switch to goat’s milk due to perceived sensitivities to cow’s milk. However, because the proteins in goat’s milk are closely related to those in cow’s milk, switching between them typically doesn’t resolve sensitivities. Nutritionally, the two are quite similar in their sugar, fat, and protein content—including their naturally low levels of vitamin D.

In Australia, we don’t have a lot of published data on the vitamin D content of goat’s milk, but international food composition databases have found that goat’s milk vitamin D content can range from 0.6–2.8 μg/kg and cow’s milk from 0.3–1.0 μg/kg.² Seasonal variations in vitamin D content of cow’s milk has been well documented, with concentrations found to be higher in the summer months than in the winter.³ These same seasonal variations may affect goat’s milk too.

Australians need between 5-15 μg of vitamin D every day, depending on your age.³ For most of us, our main source of vitamin D comes from sunlight, but small amounts are also found naturally in some foods like fatty fish (e.g. mackerel, salmon) and eggs. In Australia, by law, margarine is fortified with vitamin D. Some dairy foods (including milk) may have added vitamin D. If a brand of cow or goat milk states that there is added vitamin D on the food label, the amount will be listed in the nutrition information panel on the back of the label. 

References

1. National Health and Medical Research Council. Australian Dietary Guidelines Canberra: Commonwealth of Australia; 2013.
2. Schmid A, Walther B. Natural Vitamin D Content in Animal Products Adv Nutr. 2013 Jul; 4(4): 453–462.
3. Wer RR, Strain JJ et al. Environmental and genetic factors influence the vitamin D content of cows’ milk. Proceedings of the Nutrition Society (2017), 76, 76–82
4. National Health and Medical Research Council. Nutrient Reference Values for Australia and New Zealand. Commonwealth of Australia; 2006