How big of a role does vitamin D play in calf health?

Calf disease in Ireland is a major problem; it causes particular issues on dairy calf-to-beef farms.

However, calf disease is not just limited to these systems and a disease outbreak on any farm can lead to losses. It can also have a significant negative effect on the health and thrive of the calf going forward.

Calves are most at risk when they are young and, as a result, extra care must be taken to ensure calves build up adequate immunity to these diseases. In addition, underfed calves are most at risk of disease.


Recent research from Teagasc shows that programming the immune system begins pre-birth and continues during the early-life period.

During this period, as protection from calves’ mothers’ antibodies begins to reduce, the calves are more susceptible to disease until a vaccination has been administered or natural immunity develops.

Vitamin D, Teagasc says, is a nutrient that bridges the nutritional and immunological systems by providing the metabolic requirements for growth, as well as an immune response.

Teagasc research has highlighted the levels of vitamin D in Irish newborn calves for the first time. However, according to Teagasc, correct levels of vitamin D have not been established in cattle.

However, based on international data, values of 30ng/ml are generally thought to be required for optimal health, Teagasc says.


Teagasc results show that it could take four months before Irish spring-born calves reach this target and, as a result, they may be more susceptible to disease.

According to Teagasc, vitamin D is included in calf rations; however, these rations are not always available to young calves, as they are on a milk-based diet.

Furthermore, as the majority of spring calving takes place indoors, it is possible that calves may be susceptible to disease due to a vitamin D deficiency.

Future research will be needed to identify if direct supplementation of the mother and the newborn calf is necessary; this may improve young calves’ immune systems during the high disease risk periods.