Fat-tailed Awassi and German Mutton Merino sheep under semi-arid conditions: 3. Body temperatures and panting rate
- 1 October 1977
- journal article
- research article
- Published by Cambridge University Press (CUP) in The Journal of Agricultural Science
- Vol. 89 (2) , 399-405
- https://doi.org/10.1017/s002185960002832x
Abstract
Summary: Rectal, external auditory meatus and skin temperatures and panting rates were measured in native fat-tailed Awassi and imported German Mutton Merino (GMM) sheep. The Awassi evolved under desert conditions, have a localized fat deposit, coarse carpet wool, long pendulous ears and long, spiral horns (males). In contrast, the GMM evolved under temperate conditions, have well-distributed fat, medium fine wool, short, straight ears and are polled. The study was carried out during the summer in the northern part of the Negev desert.The mean daily rectal temperature fluctuation was higher (P < 0·01) in the GMM than in the Awassi (1·78 °C v. 1·08 °C). The external auditory meatus temperature was lower than the rectal temperature by 1·5 °C in the GMM and by 1·7 °C in the Awassi, indicating a cooler brain temperature. The maximum skin temperature was similar to the maximum rectal temperature in both breeds, thus sweating was of little importance. The panting rate of the GMM increased fivefold (40·6–199·4 pants/min) whilst the rate of the Awassi increased fourfold (35·3–135·0 pants/min). There was no between-breed difference in either the rectal temperature or panting rate until 25–30 °C ambient temperature and it is thought that the higher rectal temperature of the GMM at this ambient temperature might have triggered off the higher panting rate. It seems that the GMM use panting to a greater extent than the Awassi whereas the Awassi dissipate heat through the skin more efficiently than the GMM. It is concluded that both breeds are thermostable, much of the between-breed difference in rectal temperature can be attributed to their anatomical differences.This publication has 18 references indexed in Scilit:
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