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Survey of Serum Vitamin D Status across Stages of Swine Production and Evaluation of Vitamin D Premixes

24 February 2015

Subclinical hypovitaminosis D appears to be more common than previously thought, especially in commercial pigs kept indoors, according to a new study at Iowa State University.

The objectives of this investigation, published in Journal of Swine Health and Production, were to evaluate the serum 25-hydroxyvitamin D – 25(OH)D – concentrations in pigs of different age groups, to determine if 25(OH)D concentrations varied with season, and to assess the quality of vitamin D supplements used in swine diets from multiple commercial suppliers.

Darin Madson of Iowa State University and co-authors there and with Choice Genetics, the University of Wisconsin and Heartland Assays submitted a total of 1,200 serum samples to a diagnostic laboratory for routine surveillance and assay for serum 25(OH)D concentrations.

Vitamin D premix samples were obtained from suppliers and analysed at two laboratories over a nine-month period.

In all age categories, 25(OH)D concentrations in numerous serum samples were lower than reference values.

In the nursery, finisher and boar age categories, there was a difference between the months of January and June (P<0.05), with June samples containing higher quantities of circulating 25(OH)D.

Serum samples from outdoor herds had higher 25(OH)D concentrations than samples from confined pigs (P<0.01).

Among the supplement samples evaluated, no individual supplement had a concentration of 25(OH)D significantly lower than 500,000IU per gram.

Madson and co-authors conclude their results reveal that commercial swine may be deficient in serum vitamin D at varying times of the year.

They added that feed supplement vitamin D concentrations may also vary although, under the conditions of this study, the premixes were not significantly lower in vitamin D than the expected range.


Arnold J., D.M. Madson, S.M. Ensley, J.P. Goff, C. Sparks, G.W. Stevenson, T. Crenshaw, C. Wang and R.L. Horst. 2015. Survey of serum vitamin D status across stages of swine production and evaluation of supplemental bulk vitamin D premixes used in swine diets. J Swine Health Prod. 23:28–34.

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February 2015

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