Seasonal changes in growth rate, feed intake, growth hormone, and thyroid hormones in young male reindeer ( Rangifer tarandus tarandus )

The levels of thyroxine (T 4 ), triiodothyronine (T 3 ), and growth hormone (GH) in blood serum from young male reindeer have been measured and compared with changes in body weight and feed intake during ad libitum and restricted feeding. All three hormones fluctuated during the year. T 3 changed in...

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Bibliographic Details
Published in:Canadian Journal of Zoology
Main Authors: Ryg, Morten, Jacobsen, Endre
Format: Article in Journal/Newspaper
Language:English
Published: Canadian Science Publishing 1982
Subjects:
Online Access:http://dx.doi.org/10.1139/z82-002
http://www.nrcresearchpress.com/doi/pdf/10.1139/z82-002
Description
Summary:The levels of thyroxine (T 4 ), triiodothyronine (T 3 ), and growth hormone (GH) in blood serum from young male reindeer have been measured and compared with changes in body weight and feed intake during ad libitum and restricted feeding. All three hormones fluctuated during the year. T 3 changed in response to changes in feed intake. T 4 and GH seemed to have basic seasonal patterns, which were modified by differences in feed intake. GH rose to high levels in late winter – early spring. T 4 levels were higher in summer than in winter, corresponding roughly to changes in weight gain and feed intake.