Clinical cases of metabolic bone disease in swine, such as rickets and osteomalacia, have been linked to hypovitaminosis D. Since the primary source of vitamin D for most US swine is feed supplementation, an evaluation of bulk source vitamin D was performed. Five different swine feed suppliers were solicited over a nine month period for bulk source vitamin D samples. These samples were blinded, to keep anonymity, split, and then sent to two separate laboratories to evaluate vitamin D concentration. There was a total of 45 samples evaluated (90 assays), and no individual supplement source was found to be significantly lower than the expected concentration of 500,000 IU/lb. However, variation between sources and testing labs were noted. Results of this study suggest that the rise in clinical swine metabolic bone disease does not appear to be associated with bulk vitamin D that is being supplied to diet manufactures.
Iowa State University, Veterinary Diagnostic Laboratory
1600 South 16th Street
Ames, IA 50011