Hostname: page-component-cd9895bd7-7cvxr Total loading time: 0 Render date: 2024-12-27T19:04:07.875Z Has data issue: false hasContentIssue false
  • English
  • Français

Cold-induced inhibition of thermal panting in shorn sheep. 2. Effect of previous acclimatization to cold

Published online by Cambridge University Press:  02 September 2010

J. Slee
J. Slee
Affiliation:
ARC Animal Breeding Research Organisation, West Mains Road, Edinburgh EH9 3JQ
Get access

Summary

1. Short cold exposures (2 hr at 18° or 8°C) were used to delay or block panting during subsequent heat stress in shorn Merino and Scottish Blackface sheep. The effect of previous acclimatization to cold upon the block to thermal panting was studied.

2. After acclimatization the block was reduced, but less in Merinos than in Blackfaces. In Blackfaces, the reduction effect was inconsistent after short periods of acclimatization, but became significant after prolonged (3 weeks) acclimatization.

3. Acclimatization produced elevations in heart rate and body temperature implying increased heat production. Variation in block reduction between breeds and between individuals was related to these presumed changes in heat production. Sheep with highly elevated metabolic rates showed complete block prevention. 4. After cold exposure ceased, elevated heat production disappeared within 8 days and the block returned.

5. It was concluded that elevated heat production resulting from acclimatization caused block prevention partly because increased heat storage cancelled the heat debt otherwise incurred during blocking treatment and partly because the increased requirement for heat dissipation overruled the respiratory centre block.

Type
Research Article
Information
Animal Production , Volume 17 , Issue 1 , August 1973 , pp. 9 - 19
Copyright
Copyright © British Society of Animal Science 1973

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Bugh, J. 1963. Inhibition of thermal polypnoea in the closely shorn sheep. J. Physiol. 168: 764–781.Google Scholar
Joyce, J. P. and Blaxter, K. L. 1964. The effect of air movement, air temperature and infrared radiation on the energy requirements of sheep. Br. J. Nutr. 18: 5–27.CrossRefGoogle ScholarPubMed
Slee, J. 1968. Body temperature and vasomotor responses in Scottish Blackface and Tasmanian Merino sheep subjected to slow cooling. Anim. Prod. 10: 265–282.Google Scholar
Slee, J. 1970. Resistance to body cooling in male and female sheep and the effects of previous exposure to chronic cold, acute cold and repeated short cold shocks. Anim. Prod. 12: 13–21.Google Scholar
Slee, J. 1971. Physiological factors affecting the energy cost of cold exposures. Proc. Nutr. Soc. 30: 215–221.Google Scholar
Slee, J. 1972. Habituation and acclimatization of sheep to cold following exposures of varying length and severity. J. Physiol. 227: 51–70.CrossRefGoogle ScholarPubMed
Slee, J. 1973. Cold-induced inhibition of thermal panting in shorn sheep. I. Effect of intensity of cold exposure. Anim. Prod. 16: 271–283.Google Scholar
Slee, J. and Sykes, A. R. 1967. Acclimatization of Scottish Blackface sheep to cold. 1. Rectal temperature responses. Anim. Prod. 9: 333–347.Google Scholar
Sykes, A. R. and Slee, J. 1968. Acclimatization of Scottish Blackface sheep to cold. 2. Skin temperature, heart rate, respiration rate, shivering intensity and skinfold thickness. Anim. Prod. 10: 17–35.Google Scholar
Sykes, A. R. and Slee, J. 1969a. Cold exposure of Southdown and Welsh Mountain sheep. 1. Effects of breed, plane of nutrition and previous acclimatization to cold upon resistance to body cooling. Anim. Prod. 11: 65–75.Google Scholar
Sykes, A. R. and Slee, J. 1969b. Cold exposure of Southdown and Welsh Mountain sheep. 2. Effects of breed, plane of nutrition and previous acclimatization to cold upon skin temperature, heart rate, shivering and respiration rate. Anim. Prod. 11: 77–89.Google Scholar
Webster, A. J. F. 1967. Continuous measurement of heart rate as an indicator of the energy expenditure of sheep. Br. J. Nutr. 21: 769–785.CrossRefGoogle ScholarPubMed