Research conducted at Kansas State University (McEllhiney and Tangprasertchai, 1983) indicated that the dispersion of microingredients in finished feeds is not significantly affected by first diluting microingredients in a premix or by the level of dilution in a premix. In those experiments, a drug and an iron particle tracer were added into the batch mixer undiluted as supplied by the manufactures as a control. Then, premixes were prepared by diluting the drug, tracer, vitamins and trace minerals at one part microingredient to one part diluent (1:1) and, similarly, at dilution ratios of 1:5, 1:10, 1:25, and 1:50. Each dilution was added to a separate batch of 32% medicated supplement for feedlot cattle. Ten samples of the final feed were drawn from each batch of supplement and assayed for the test materials, and the entire six batch series of tests was duplicated.