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Physiological and endocrinological reactions to cold stress in the angora goat

D. WENTZEL, K. S. VILJOEN and L. J. J. BOTHA, Agricultural Research Institute of the Karoo Region,

Agricultural College Grootfontein, Middelburg C.P., 5900

 

ABSTRACT

Physiological and endocrinological reactions to cold stress were investigated in pregnant mature and young barren Angora does. According to the results pregnant mature animals showed a better resistance against external cold as compared to young barren animals.

Exposure to cold resulted in an initial increased metabolic rate of heat production as indicated by an elevated heart rate and increased blood glucose concentration. In animals which collapsed during the experiment, the heart rate, blood glucose concentration and rectal temperature, however, decreased to subnormal values prior to the stage of collapse.

Following cold stress, circulating corticosteroids and thyroxine in experimental animals increased abruptly. Animals which survived the 48-hour experimental period maintained a relatively high heart rate, normal body temperature and a relatively high plasma thyroxine concentration throughout the experimental period.

 

Uittreksel

FISIOLOGIESE EN ENDOKRlNOLOGIESE REAKSIES VAN DIE ANGORABOK OP KOUE

Fisiologiese en endokrinologiese reaksies op koue is by volwasse dragtige en jong nie-dragtige Angorabokooie ondersoek. Volgens die resultate het volwasse dragtige diere 'n beter weerstand teen die koue, as jong nie-dragtige ooie, gebied.

Blootstelling aan koue het 'n aanvanklike verhoging in die metaboliese spoed van hitteproduksie tot gevolg gehad, soos aangedui deur die verhoging in hartspoed en bloedglukosekonsentrasie. Diere wat as gevolg van die koue ineengestort het, het egter in laasgenoemde stadium 'n abnormale lae hartspoed, bloedglukosekonsentrasie en rektale temperatuur gehad.

Na die aanvang van koue behandeling het sirkulerende kortikosteroiede en tiroksien van eksperimentele diere 'n vinnige styging getoon. Diere wat die 48-uurproefperiode deurstaan het, het deurgaans 'n relatiewe hoë hartspoed, normale liggaamstemperatuur en 'n relatiewe hoë plasmatiroksienpeil gehandhaaf.

 

Published

Agroanimalia 11(2) 1979