HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Lodge, J. R. Articles by Reineke, E. P. Search for Related Content PubMed Articles by Lodge, J. R. Articles by Reineke, E. P.

Estimating the Thyroid Activity of Dairy Heifers¹

Departments of Dairy and Physiology Michigan State University, East Lansing

ABSTRACT

Thyroid secretion in calves was measured with radioactive iodine, injected subcutaneously. There were individual and breed differences in iodine assimilation, the average being 41.6%. The calves were able to recycle iodine through the thyroid. Editor.

In 1952, Henneman et al. (4) reported the development of a method for quantitatively measuring the thyroid secretion rate of intact individual sheep. The procedure introduced by these authors involves direct counts of radioactivity in the thyroid region to determine the amount of thyroxine that must be given daily to suppress the output of previously collected I¹³¹ from the gland. Because of the methods of computation employed, this has been referred to as the extrapolation technique. The method was confirmed and extended by experiments in rats by Reineke and Singh (10), It has been used by Henneman et al. (5) and Singh et al. (11) to study some of the environmental and physiological factors related to thyroid function in sheep.

¹ Approved by the Director, Michigan Agricultural Experiment Station as Journal Article No. 1935.

² A portion of these data is taken from a thesis by James R. Lodge to be presented to the School for Advanced Graduate Studies, Michigan State University, in partial fulfillment of the requirements for the Ph.D. degree.