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Heat tolerance of different genetic groups of sheep exposed to elevated temperature conditions

Published online by Cambridge University Press:  27 March 2009

M. Singh
Affiliation:
Central Sheep and Wool Research Institute, Avikanagar, India 304501
T. More
Affiliation:
Central Sheep and Wool Research Institute, Avikanagar, India 304501
A. K. Rai
Affiliation:
Central Sheep and Wool Research Institute, Avikanagar, India 304501

Summary

Indian Chokla and Malpura and their crosses with exotic Rambouillet and pure bred Rambouillet sheep were exposed to increasing temperature (20, 25, 30, 35 and 42 °C), or to 40 °C for 6 ha day for about a week, or suddenly to 40·4 or 44·2 °C to study their relative heat tolerance. Pronounced increase in the frequency of respiration under hot conditions together with increase in rectal temperature (under 44·2 °C) of Rambouillet contrasted with the physiological responses of the native breeds of sheep. Under thermal stress the Chokla and Malpura consumed more feed than the Rambouillet or the half breds. The Rambouillet × Chokla or the Rambouillet × Malpurahalf breds were apparently more heat tolerant than the Rambouillet sheep.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1980

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