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 Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Shutt, D. A. Articles by Fell, L. R. Search for Related Content PubMed PubMed Citation Articles by Shutt, D. A. Articles by Fell, L. R.

Comparison of Total and Free Cortisol in Bovine Serum and Milk or Colostrum

Department of Agriculture, Hawkesbury Agricultural Research Unit, P.O. Box 217, Richmond, New South Wales, 2753, Australia

ABSTRACT

Total (free plus protein-bound) and free cortisol concentrations in paired samples of serum and skim milk or colostrum were determined by specific radioimmunoassay after extraction or ultrafiltration. For 11 cows in established lactation mean total cortisol concentrations ± SE in serum and milk were 4.5 ± .7 ng/ml and .35 ± .06 ng/ml, respectively. Concentrations of free cortisol in serum and milk were about .3 ng/ ml, which is at the lower limit of the present assay. Following 200 IU Synacthen injection to 5 cows, total cortisol in serum and milk rose to 67 ± 6.0 ng/ml and 11.4 ± 1.5 ng/ml by 8 h postinjection, while free concentrations increased to 4.3 ± .7 ng/ml and 6.5 ± .8 ng/ml in serum and milk, respectively. Eight additional cows were sampled at 1 to 2 d after parturition, and total cortisol in serum and colostrum was 16.6 ± 1.6 ng/ml and 4.4 ± 1.3 ng/ml, and free cortisol was 2.4 ± .4 ng/ml and 1.8 ± .5 ng/ml, respectively. Free cortisol concentrations in colostrum or in milk from cows in established lactation, before or after adrenal stimulation, are directly related to free cortisol concentrations in the blood, while the bound cortisol in milk is more related to these two stages of lactation rather than the bound hormone in the blood. Measurement of free cortisol in milk should allow the monitoring of changes in plasma free cortisol in studies of stress in dairy cows.

This article has been cited by other articles:

				L. Gygax, I. Neuffer, C. Kaufmann, R. Hauser, and B. Wechsler Milk cortisol concentration in automatic milking systems compared with auto-tandem milking parlors. J Dairy Sci, September 1, 2006; 89(9): 3447 - 3454. [Abstract] [Full Text] [PDF]