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 Google Scholar Google Scholar Articles by Dunlap, S. E. Articles by Beneshek, L. L. Search for Related Content PubMed PubMed Citation Articles by Dunlap, S. E. Articles by Beneshek, L. L.

Clearance of Serum Cortisol in Suckled and Nonsuckled Postpartum Beef Cows¹

University of Georgia and US Department of Agriculture, Athens 30602

Abstract

Clearance of Cortisol from the sera of suckled (S) and nonsuckled (NS) beef cows was studied on days 14 ± 1 and 28 ± 1 (mean ± SE) postpartum (periods 1 and 2, respectively). Eight multiparous Angus cows (325 kg to 445 kg) were assigned at calving to S (n = 4) and NS (n = 4) treatments. Basal Cortisol concentrations tended to be higher (P<.10) in S (19.0 ± 1.3 ng/ml) than in NS (12.9 ± .9 ng/ml) cows across both periods. After administration of 20 mg of Cortisol, serum Cortisol concentrations increased (P<.01) similarly in S and NS cows to 122.1 ± 6.4 and 165.6 ± 11.5 ng/ml at 2 min postinjection at periods 1 and 2, respectively. Clearance of Cortisol from the body was evaluated by biological half-life (t), volume of distribution (V_d) and total body clearance (TBC) of Cortisol. Serum Cortisol had a similar t1/2 in S (32.5 ± 2.3 min) and NS (29.2 ± 3.2 min) cows and did not not differ between sampling periods. V_d did not differ (P>.3) between S (248 ± 29 liters) and NS (199 ± 14 liters) cows across both periods, but was greater (P<.05) at period 1 than at period 2 for both S and NS cows. Total body clearance was similar in S (5.2 ± .4 liters/min) and NS (5.0 ± .6 liters/min) cows and was similar at both sampling periods. On the basis of these results, we conclude that clearance of Cortisol from the serum was not affected by lactational status or by postpartum interval, but that the volume of distribution of Cortisol in the body decreased during the postpartum period studied.

¹ This research was supported by State and Hatch funds allocated to the Georgia Agr. Exp. Station. The authors acknowledge the help of Ms. Del Little with the statistical analysis.

² Dept. of Anim. and Dairy Sci.

³ Dept. of Pharmaceutics.

⁴ Richard B. Russell Agricultural Research Center.