Seasonal variations in concentrations of circulating thyroid hormones and their relationships to diet in the white-tailed deer

Three experiments were conducted to determine the effect of energy, protein, sex, and time on serum T4 and T3 concentrations. All sampling periods occurred at 28-day intervals. In the first experiment, (March-February) 7 adult bucks were placed on 2 feed levels, ad libitum or 25% restricted. Feed consumption of ad libitum deer was highest (P≤0.05) from June-October, fell in November, and remained low through March. Body weights of both groups were highest (P≤0.05) from September-October; lowest from March-April. Serum T4 was highest (P≤0.05) in May and July, and lowest in November. From November-February, restricted deer had lower T4 concentrations (P<0.01) than did ad libitum deer. Serum T3 was highest from May-August; lowest in November. Ad libitum had higher T3 concentrations (P<0.01) than the restricted animals. The second experiment compared the effects of energy and protein on body weight, and serum T4 and T3 of 24 fawns (12 male) from October-May. Feed intake fell gradually to low levels maintained from January-March, then increased slightly. Body weight gain was initially rapid (P<0.01), minimal from November-March, and slow through May. Serum T4 was highest in late April; lowest in October and February. Maximum serum T3 concentrations occurred in April; lowest values in February. Females had higher T4 and T3 values than did males. The third experiment involved 1 adult buck. Blood samples were drawn every 2 hours for a 24-hour period via a jugular catheter. Serum T4 and T3 concentrations were highest from 1600-2000 hours (EST), lowest at 1000 hours.

Name thesis:degree_name

M.S.

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Fisheries and Wildlife Sciences

Department dc:contributor.department

Fisheries and Wildlife Sciences

Grantor dc:publisher

Virginia Polytechnic Institute and State University

Year dc:date.issued

1979

Author dc:creator

• Oelschlaeger, Anne

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Handle dc:identifier.uri

http://hdl.handle.net/10919/101192

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/101192