Note on the Pattern of Diurnal Fluctuationsof Some Physiological Responsesin Shaded and Unshaded Karakachanska Sheep

摘要

Five Karakachanska ewes were exposed to direct solar radiation 32 or kept in shade for 14 hours before and following shearing. Rectal temperature, respiratory rate and heart rate were recorded from 7 a.m. to 9 p.m. Plasma levels, of indol, cholesterol, urea and total protein were determined at 8 a.m. and 2 p.m. Direct solar radiation caused significant increase of rectal temperature, respiratory rate and heart rate in shorn ewes, but had no effect on rectal temperature in unshorn ewes. However unshorn ewes exposed to sun showed an enhanced respiratory activity. The shorn ewes kept in shade had lower rectal temperature and respiratory rate than the unshorn ewes. Heart rate was higher in shorn ewes either exposed to sun or kept in shade. Plasma indol, cholesterol, urea and total protein were unaffected by the exposure to heat. Despite the general opinion that Karakachanska sheep is resistant to the abiotic environmental factors, present data suggest that this sheep breed is vulnerable to solar radiation during the first days following shearing.