Hostname: page-component-cd9895bd7-jn8rn Total loading time: 0 Render date: 2024-12-23T02:30:30.960Z Has data issue: false hasContentIssue false

Early reproductive failure of ewes in a hot environment IV. The ovary

Published online by Cambridge University Press:  27 March 2009

Margaret Ryle
Affiliation:
Department of Physiology, University of Melbourne

Extract

1. A balanced factorial experiment was carried out with 48 Merino ewes. There were two levels of each of the four factors: environmental temperature, thyroxine status, vitamin A intake and progesterone status. Each ewe was killed at 25 days' pregnancy. The ovaries were removed, weighed and examined histologically.

2. There were no significant treatment effects on ovarian weight, corpus luteum diameter, lutein cell frequency, lutein cell nuclear diameter, the number of Graafian follicles exceeding 0·9 or 1·9 mm. diameter, or mean follicle diameter. The results suggest that with more animals heat might prove to depress ovarian weight and vitamin A to increase ovarian weight, corpus luteum diameter and the number of large follicles.

3. There were no significant differences between the mean values for those ewes with live embryos and those with dead ones with respect to any of the above indices.

4. The results support the conclusion that variations in embryonic viability due to the experimental treatments were not mediated primarily through variations in ovarian hormone secretion.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1963

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

Allen, D. M. & Lamming, G. E. (1961). J. Agric. Sci. 56, 69.CrossRefGoogle Scholar
Bell, T. D., Casida, L. E. & Darlow, A. E. (1941). Endocrinology, 28, 441.CrossRefGoogle Scholar
Chu, J. P. (1944). Endocrinology, 34, 90.CrossRefGoogle Scholar
Cole, H. H. & Miller, R. F. (1935). Amer. J. Anat. 57, 39.CrossRefGoogle Scholar
Moore, N. W. & Rowson, L. E. A. (1959). Nature, Lond., 184, 1410.Google Scholar
Nalbandov, A. V., Moore, W. W. & Norton, H. W. (1955). Endocrinology, 56, 225.Google Scholar
Ryle, M. (1961). J. Agric. Sci. 57, 1.Google Scholar
Ryle, M. (1962 a). J. Agric. Sci. 58, 137.CrossRefGoogle Scholar
Ryle, M. (1962 b). Aust. J. Sci. 25, 112.Google Scholar
Ryle, M. (1963). J. Agric. Sci. 60, 95.CrossRefGoogle Scholar
Warbritton, V. (1934). J. Morph. 57, 181.CrossRefGoogle Scholar
Wimsatt, W. A. (1950). Amer. J. Anat. 87, 391.CrossRefGoogle Scholar