Biliary Secretion of Iodine in Calves

Abstract

Biliary secretion of iodine was studied in dairy bull calves. An average of 24.3% of the radioactivity appeared in the bile of calves within 24 hrs. after cannulation of bile ducts and injection of thyroxine I131. When a similar injection of labeled thyroxine was administered to intact calves, only 18.0% of the radioactivity appeared in the 24-hr. fecal sample. From these results it is suggested that fecal iodine loss and other temporary pathways for modification of thyroid function and iodine loss in cattle could result in transient hypothyroidism. The relation of these factors to ovarian cyst etiology of dairy cattle is discussed.