Calcium Iodate and Pentacalcium Orthoperiodate as Sources of Supplemental Iodine for Cattle

Abstract

The nutritional availability of iodine from calcium iodate, pentacalcium orthoperiodate (PCOP), and sodium iodide was compared using six near-term pregnant cows. Nine days before expected parturition, three were orally dosed with 2 mCi 125I-labeled calcium iodate and three orally with 2 mCi 125-labeled pentacalcium orthoperiodate. Each animal was orally given 2 mCi Na131I simultaneously with the 125I doses. One animal from each group was killed seven days after dosing and four were allowed to calve normally. Blood plasma radioiodine concentrations, thyroid uptake, and urinary and fecal radioiodine excretions were comparable for each of the iodine compounds during seven days after dosing. Calcium iodate and pentacalcium orthoperiodate were equally available as iodide for transfer to the unborn fetus as indicated by equal 125I and 131I concentrations in slaughter samples including maternal and fetal thyroids, abomasal content, placental fluids, cotyledons, and fetal bladder content and bile. Thyroid and plasma 125I levels equaled corresponding 131I values for four cows and calves during six days following parturition. It was concluded that calcium iodate and pentacalcium orthoperiodate are adequate supplemental iodine sources for cattle. © 1968, American Dairy Science Association. All rights reserved.