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The effects of L-thyroxine on sheep and wool production

Published online by Cambridge University Press:  27 March 2009

F. M. Labban
F. M. Labban
Affiliation:
School of Agriculture, Durham University, and Animal Production Department, Ministry of Agriculture, Cairo, Egypt
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Extract

1. Three experiments were carried out in this study to investigate the effects of L-thyroxine on sheep and wool production. In the first experiment L-thyroxine was orally administered to ewe lambs from weaning time for a period of 48 weeks. In the second experiment, ten uniform yearling ewes were selected and were randomly distributed into two groups of five; one group was fed daily 7 mg. L-thyroxine per ewe for 7 weeks from 1 April 1954. In the third experiment L-thryoxine was fed as a supplement to lactating ewes over the second to the sixteenth week of lactation at the rate of 7 mg. daily per ewe.

2. Differences in both body weight and rectal temperature between the experimental and control groups were not statistically significant. The treatment had also no effect on the body weight of the ewes during lactation.

3. Wool growth, as measured by the weight of keratine production per unit of surface area, was increased significantly during the period of thyroid treatment. This increase in wool production was due to an increase in the length of the wool fibres but not to any observable increase in the diameter of the fibres. This effect is different from that produced by a high plane of nutrition where extra wool production is characterized by increase in both length and diameter.

4. It was observed that the treated ewes exhibited hypersexual activities characteristic of male behaviour, i.e. jumping and mounting other animals.

5. There was a significant increase in the rate of milk secretion over the period. 2–8 weeks. This increase was reflected in an improved live-weight increase of the lambs which were suckling these treated ewes. The difference in milk yield between treated and untreated ewes was not maintained over the nine to ten weeks period of the lactation.

6. As a result of these studies it has been established that the normal milking performance of Border Leicester × Scotch Blackface ewes is high as compared with that of other breeds or crosses reported in the literature. The shape of their lactation curve suggests, however, that it is possible that after the eighth week of lactation the ewes may become competitors with their lambs for available grazing. Expressed in another way ewes become less efficient as converters of their food into milk for lambs, for which milk is becoming proportionately a less important component of the diet. This finding raises the question of the possibilities of providing creep grazing or supplementary feeding for lambs so that their growth potential is fully realized. Alternatively, there may, under farm conditions, be grounds for weaning lambs at about 12 weeks so that they may have preferential treatment in regard to available grazing rather than to adopt customary weaning at about 16–18 weeks of age.

7. It has been established that a close relationship exists between the milk yield of dams and the growth, rate of their lambs under normal grazing conditions. Because of this strong relationship a regression formula has been tentatively advanced which may permit workers to select ewes for milk yield on the basis of the live-weight gain of their lambs.

Type
Research Article
Information
The Journal of Agricultural Science , Volume 49 , Issue 1 , May 1957 , pp. 26 - 50
Copyright
Copyright © Cambridge University Press 1957

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References

REFERENCES

Bailey, G. L., Bartlett, S. & Folley, S. J. (1949), Nature, Lond., 163, 800.CrossRefGoogle Scholar
Barber, R. S., Braude, R. & Mitchell, K. G. (1953). Chem. & Ind. p. 410.Google Scholar
Barnicoat, C. R., Logan, A. G. & Grant, A. I. (1949). J. Agric. Sci. 39, 44, 237.CrossRefGoogle Scholar
Barrick, E. R., Beeson, W. M., Andrews, F. N. & Harper, C. (1949). J. Anim. Sci. 8, 243.CrossRefGoogle Scholar
Blaxter, K. L. (1945). J. Endocrin. 4, 237.CrossRefGoogle Scholar
Blaxter, K. L. (1946). J. Agric. Sci. 36, 117.CrossRefGoogle Scholar
Blaxter, L. K. (1948). J. Agric. Sci. 38, 207.CrossRefGoogle Scholar
Bonsma, F. N. (1939). Univ. Pretoria Public Series (Agric), no. 48.Google Scholar
Boyden, S. V. (1951). J. Exp. Med. 93, 107.CrossRefGoogle Scholar
Braude, R. (1947). J. Agric. Sci. 37, 45.CrossRefGoogle Scholar
Brody, S. (1945). Bioenergetics and Growth. Rheinhold Publ. Co.Google Scholar
Burns, M. (1954). J. Agric. Sci., 44, 86.CrossRefGoogle Scholar
Burris, M. J. & Bangus, C. A. (1955). J. Anim. Sci. 14, 186.CrossRefGoogle Scholar
Butcher, E. O. (1940). Amer. J. Physiol. 129, 553.CrossRefGoogle Scholar
Chang, H. C. (1926). Amer. J. Physiol. 77, 562.CrossRefGoogle Scholar
Chang, H. C. & Feng, T. P. (1929). Chin. J. Physiol. 3, 57.Google Scholar
Coop, I. E. (1950). J. Agric. Sci. 40, 311.CrossRefGoogle Scholar
Coop, I. E. (1953). J. Agric. Sci. 43, 456.CrossRefGoogle Scholar
De Fremery, P. (1936). J. Physiol. 87, 50.Google Scholar
Dickson, G. R. (1956). Experimental work at Cookle Park Research Farm.Google Scholar
Emmens, G. W. (1942–1944). J. Endocrin. 3, 64.CrossRefGoogle Scholar
Farber, E. M. & Lobitz, W. C. (1952). Ann. Rev. Physiol. 14, 519.CrossRefGoogle Scholar
Ferguson, K. A. (1951). Ph.D Thesis, University of Cambridge.Google Scholar
Ferguson, K. A., Carter, H. B. & Hardy, M. H. (1949). Aust. J. Sci. Res. B, 2, 42.Google Scholar
Folley, S. J. (1952). Personal communication.Google Scholar
Hammond, J. (1943). Proc. Nutr. Soc. 2.Google Scholar
Hammond, J. (1945). J. Endocrin. 4, 169.CrossRefGoogle Scholar
Henderson, A. E. (1953). J. Agri. Sci. 43, 12.CrossRefGoogle Scholar
Hunter, G. L. (1954). Ph.D Thesis, University of Cambridge.Google Scholar
Koger, M. & Turner, C. W. (1943). Res. Bull. Mo. Agric. Exp. Sta. no. 377.Google Scholar
Kumaran, J. D. S. & Turner, C. W. (1949). Poult. Sci. 28, 653.CrossRefGoogle Scholar
Leberthe, P., Bertone, E. & Washburn, L. E. (1949). J. Anim. Sci. 8, 624.Google Scholar
Leblond, C. P. (1954). Endocrinology, 54, 104.CrossRefGoogle Scholar
Leech, F. B. (1950). J. Endocrin. 7, 42.CrossRefGoogle Scholar
Leech, F. B. & Bailey, G. L. (1953). J. Agric. Sci. 43, 236.CrossRefGoogle Scholar
McQuillan, M. T., Trikojus, V. M., Campbell, A. D. & Turner, A. W. (1948). Brit. J. Exp. Path. 29, 94.Google Scholar
Maqsood, M. (1951). Ph.D Thesis, University of Cambridge.Google Scholar
Maqsood, M. (1952). Biol. Rev. 27, 281.CrossRefGoogle Scholar
Marine, D. (1939). Bull. N.Y. Acad. Med. 15, 790.Google Scholar
Marston, H. R. (1948). Aust. J. Sci. Res. 1, 362.Google Scholar
Marston, H. R. & Peirce, A. W. (1932). Aust. J. Exp. Biol. Med. 10, 203.CrossRefGoogle Scholar
Moore, L. A. (1946). J. Dairy Sci. 29, 22.Google Scholar
Mukrer, M. E., Warner, D. R., Palmer, Z. & Hogan, A. G. (1947). J. Anim. Sci. 7, 489.Google Scholar
Neiding, R. E. & Iddings, E. J. (1919). J. Agric. Res. 17, 19.Google Scholar
Neumann, A. L., Potton, H. B. & Gifford, W. (1950). J. Anim. Sci. 9, 680.CrossRefGoogle Scholar
Oloufa, M. M., Bogart, R. & McKenzie, F. (1951). Ore. Agric. Exp. Sta. Tech. Bull. no. 20.Google Scholar
Owen, J. B. (1955). Ph.D Thesis, University of Wales.Google Scholar
Perry, T. W., Beeson, W. M. & Andrews, F. N. (1950). J. Anim. Sci. 9, 48.CrossRefGoogle Scholar
Perry, T. W., Beeson, W. M. & Andrews, F. N. (1951). J. Anim. Sci. 10, 129.CrossRefGoogle Scholar
Rollins, W. C. & Guibert, H. R. (1954). J. Anim. Sci. 13, 517.CrossRefGoogle Scholar
Scow, R. O. & Simpson, M. E. (1945). Anat. Rec. 91, 209.CrossRefGoogle Scholar
Seath, D. M., Branton, C. & Groth, A. H. (1945). J. Dairy Sci. 28, 509.CrossRefGoogle Scholar
Shrewsbury, C. L., Harper, C., Andrews, F. N. & Zelle, M. R. (1942). J. Anim. Sci. 1, 126.CrossRefGoogle Scholar
Shrewsbury, C. L., Andrews, F. N., Harper, C. & Zelle, M. R. (1943). J. Anim. Sci. 2, 209.CrossRefGoogle Scholar
Simpson, S. (1924). Quart. J. Exp. Physiol. 14, 161.CrossRefGoogle Scholar
Spielman, A. A., Peterson, W. E., Fitch, J. B. & Pomeroy, B. S. (1945). J. Dairy Sci. 28, 329.CrossRefGoogle Scholar
Starke, J. S. (1953). S. Afr. J. Sci. 49, 245.Google Scholar
Swanson, R. J. & Knodt, C. B. (1948). J. Dairy Sci. 31, 660.Google Scholar
Thomson, W. & Thomson, A. M. (1953). Brit. J. Nutr. 7, 263.CrossRefGoogle Scholar
Turner, C. W. (1940). J. Dairy Sci. 23, 535.Google Scholar
Turner, C. W. & Kempster, H. L. (1948). Poult. Sci. 27, 453.CrossRefGoogle Scholar
Van Horn, W. M. (1933). Endocrinology, 17, 152.CrossRefGoogle Scholar
Van Landingham, A. H., Henderson, H. O. & Weakley, C. E. Jun. (1944). J. Dairy Sci. 27, 385.CrossRefGoogle Scholar
Verzer, F., Sailer, E. & Vidovic, V.(1952). J.Endocrin. 8, 308.CrossRefGoogle Scholar
Von, Rapp (1840). Cited by Koger M. & Turner C. W. (1943).Google Scholar
Wallace, L. R. (1948). J. Agric. Sci. 38, 243, 367.CrossRefGoogle Scholar
Wallach, D. O. & Reineke, E. P.(1949). Endocrinology, 45, 75.CrossRefGoogle Scholar
Weber, A. D. (1931). Proc. Amer. Soc. Anim. Prod. p. 228.Google Scholar
Wheeler, R. S., Hoffmann, E. & Graham, C. L. (1948). Poult. Sci. 27, 103.CrossRefGoogle Scholar