Hostname: page-component-cd9895bd7-gvvz8 Total loading time: 0 Render date: 2024-12-27T09:05:05.968Z Has data issue: false hasContentIssue false
  • English
  • Français

Studies on the adaptability of three breeds of sheep to a tropical environment modified by altitude II. Responses in body, skin and coat temperatures, cardio-respiratory frequencies and rate of moisture secretion of ewes to the diurnal fluctuation in ambient temperature during the hottest part of the year

Published online by Cambridge University Press:  27 March 2009

R. B. Symington
R. B. Symington
Affiliation:
Department of Agriculture, University College of Rhodesia and Nyasaland, Salisbury
Get access Rights & Permissions [Opens in a new window]

Extract

Responses in body, skin and coat temperatures, cardio-respiratory frequencies and rate of moisture secretion of ewes of three breeds to the diurnal fluctuation in ambient temperature were recorded in the presence and absence of drinking water during the hottest part of the Rhodesian year.

1. At 7.0 a.m. body temperatures were: Merino 102·8° F.; Persian 102·2° F. and Native 101·5° F. Between 7·0 a.m. and 1·0 p.m. body temperature rose almost equally in Persians and Natives and fell slightly in Merinos. Change in body temperature between 7.0 a.m. and 1.0 p.m. was not affected significantly by availability of water nor age of ewe, but varied with type of thermal burden (i.e. solar insolation only v. solar insolation plus artificial heat) when water was not available. Although air temperature fell towards late afternoon body temperature of Merinos and Natives rose appreciably, that of Persians only slightly.

2. At 7·0 a.m. respiratory rates were (cyc./min.): Merino 59·6; Persian 43·0; Native 29·9. Increase in rate of respiration was the main thermolytic mechanism in all breeds. Merinos had a lower threshold of respiratory response to rising ambient temperature than either hair breed but increase in rate of respiration between 7.0 a.m. and 1.0 p.m. did not differ significantly with breed or age.

3. No breed appeared to use the peripheral blood system in thermoregulation. Cardio-frequency, as a measure of this blood flow, remained almost constant with a slight tendency to fall with rise in ambient temperature.

4. In all breeds skin temperature was related to ambient and body temperatures; consequently the diurnal fluctuation in skin temperature differed in wool and hair breeds. When thermal burden was greatest Merino skin temperature fell, that of hair breeds did not.

Except at 11.0 a.m. there was a gradient between rectal, skin and air temperatures. Direct elimination of heat was thus possible for 23 hr. each day.

5. In hair breeds moisture secretion depended on insensible perspiration; consequently, rate of moisture secretion changed with body and air temperatures. In Merinos moisture for skin surface evaporation was provided by sensible and insensible perspiration. Natives may be able to sweat at temperatures higher than those recorded but it is unlikely Persians have a sweating mechanism.

6. In all breeds coat temperature was related closely to ambient temperature and changes in solar conditions evoked immediate response in coat temperature. Merino fleece apparently stabilized skin temperature whereas Persian and Native hair did not.

Type
Research Article
Information
The Journal of Agricultural Science , Volume 55 , Issue 3 , December 1960 , pp. 295 - 302
Copyright
Copyright © Cambridge University Press 1960

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

Beakley, W. R. & Findlay, J. D. (1955). J. Agric. Sci. 45, 339.CrossRefGoogle Scholar
Blaxter, K. L. (1948). J. Agric. Sci. 38, 207.CrossRefGoogle Scholar
Bonsma, J. C. (1948). Fmg in S. Afr. 23, 439.Google Scholar
Bosman, S. W. (1948). Fmg in S. Afr. 23, 169.Google Scholar
Brody, S., (1945) Bioenergeiics and growth. New York: Reinholdt Publ. Co.Google Scholar
Carter, H. B. & Dowling, D. F. (1954). Aust. J. Agric. Res. 5, 745.CrossRefGoogle Scholar
Casady, R. B., Legates, J. & Myers, R. (1956). J. Anim. Sci. 15, 141.CrossRefGoogle Scholar
Daly, R. A. & Carter, H. B. (1955). Aust. J. Agric. Res. 6, 476.Google Scholar
Eyal, E. (1954). Bull. Res. Counc. Israel, no. 3.Google Scholar
Findlay, J. D. (1950). Bull. Hannah Dairy Res. Inst. no. 9.Google Scholar
Hafez, E. S. E., Badreldin, A. L. & Sharafeldin, M. A. (1956). J. Agric. Sci. 47, 280.CrossRefGoogle Scholar
Hutchinson, H. G. & Mabon, R. M. (1954). J. Agric. Sci. 44, 121.CrossRefGoogle Scholar
Knapp, R. J. & Robinson, K. W. (1954). Aust. J. Agric. Res. 5, 570.CrossRefGoogle Scholar
Lee, D. H. K. (1950). Aust. J. Agric. Res. 1, 200.CrossRefGoogle Scholar
Lee, D. H. K. & Robinson, K. W. (1941). Proc. Roy. Soc. Queensland, 53, 121.Google Scholar
MacFarlane, W. V., Morris, R. J. & Howard, B. (1956). Nature, Lond., 178, 304.CrossRefGoogle Scholar
MacFarlane, W. V., Morris, R. J. & Howard, B. (1958). Aust. J. Agric. Res. 9, 217.CrossRefGoogle Scholar
Miller, J. C. & Monge, L. (1946). J. Anim. Sci. 5, 147.CrossRefGoogle Scholar
Miller, J. C., Monge, L. & Accame, F. (1944). J. Anim. Sci. 3, 433.Google Scholar
Paduoeva, A. L. (1955). N.A.R. (1956), p. 408, no. 1949.Google Scholar
Quinlan, J. & Mare, G. S. (1931). D.V.S. Report, S. Africa, no. 8.Google Scholar
Rieck, R. F., Hardy, M. H., Lee, D. H. K. & Carter, H. B. (1950). Aust. J. Agric. Res. 1, 217.CrossRefGoogle Scholar
Robinson, K. W. & Lee, D. H. K. (1947). J. Anim. Sci. 6, 182.CrossRefGoogle Scholar
Schmidt-Nielsen, K.(1956). The Future of Arid Lands. Washington D.C.: Amer. Assoc. for Advancement of Sci.Google Scholar
Symington, R. B. (1960). J. Agric. Sci. (in the Press).Google Scholar
Young, S. S. Y. (1955). Aust. J. Agric. Res. 6, 624.CrossRefGoogle Scholar