Metabolism of Diiodosalicylic Acid in Dairy Calves

Abstract

Diiodosalicylic acid was investigated as a source of supplemental iodine for livestock by comparing orally administered I131 iodide and I131 diiodosalicylic acid in balance trials. Although the iodine in diiodosalicylic acid was well absorbed from the gut, it was excreted more rapidly and was less available to the thyroid as compared to iodide. Thyroidal uptake of activity (as percent of dose) in 4 calves dosed with I131 diiodosalicylic acid (2 oral and 2 TV) averaged 5.5% compared to 26.8% in 2 calves dosed (oral) with I131 iodide. The data indicate that much of the iodine in diiodosalicylic acid is absorbed and excreted without being split from the ring structure.