Hostname: page-component-78c5997874-j824f Total loading time: 0 Render date: 2024-11-06T13:00:02.303Z Has data issue: false hasContentIssue false
  • English
  • Français

On the breeding season in the sheep

Published online by Cambridge University Press:  27 March 2009

J. Hammond Jr.
J. Hammond Jr.
Affiliation:
School of Agriculture, Cambridge
Get access Rights & Permissions [Opens in a new window]

Extract

Ewes. There was some variation from year to year in the times of onset and end of the breeding season; on the average it was evenly spaced on either side of the shortest day. Occasionally ewes were served and became pregnant at times well outside the normal limits of the breeding season. Lambs were allowed to suckle the ewes for as long as they would; when lambing occurred more than about 100 days from the start of the season there was no delay in onset of heat in the ewe. When lambing was later there was some delay, but the duration of the lactation anoestrum shortened to a minimum near the middle of the season and then lengthened again.

In the first half of the season the period of the oestrous cycle lengthened slowly and steadily; in the second part it became more variable, there was first a slight shortening, but upon the whole it continued to increase in length. From the start of the season the frequency of twinning increased quickly to a peak in about November and then declined for the rest of the season. At the end of the season there was a high proportion of services not fertile.

Lambs. Growth in the first 2 months was greatest in those born in May; in the fourth to sixth months it was greatest in the earliest born and least in the latest, the highest weight at 6 months old being reached by those earliest born.

Type
Research Article
Information
The Journal of Agricultural Science , Volume 34 , Issue 2 , April 1944 , pp. 97 - 105
Copyright
Copyright © Cambridge University Press 1944

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

Bissonnette, T. H. (1931). J. Exp. Zool. 58, 281.CrossRefGoogle Scholar
Bissonnette, T. H. (1941). Physiol. Zoöl. 14, 379.CrossRefGoogle Scholar
Chang, M. C. (1942). J. Endocrinol. 3, 192.CrossRefGoogle Scholar
Grant, R. (1933). Nature, Lond., 131, 802.CrossRefGoogle Scholar
Grant, R. (1934). Trans. Roy. Soc. Edinb. 58, 1.CrossRefGoogle Scholar
Hamilton, W. J., Boyd, J. D. & Hammond, J. Jr. (1944). J. Anat., Lond., 78, 5.Google Scholar
Hammond, J. (1921). J. Agric. Sci. 11, 337.CrossRefGoogle Scholar
Hammond, J. Jr. & Bhattacharya, P. (1944). J. Agric. Sci. 34, 1.CrossRefGoogle Scholar
Hammond, J. Jr. & Day, F. T. (1944). J. Endocrinol. 5 (In the press).Google Scholar
Hammond, J. Jr.Hammond, J. & Parkes, A. S. (1942). J. Agric. Sci. 32, 308.CrossRefGoogle Scholar
Kelly, R. B. & Shaw, H. E. B. (1943). Bull. Coun. Sci. Industr. Res., Aust., no. 166.Google Scholar
McKenzie, F. F. & Terrill, C. E. (1937). Res. Bull. Mo. Agric. Exp. Sta. no. 264.Google Scholar
Marshall, F. H. A. (1903). Philos. Trans. B, 196, 47.Google Scholar
Marshall, F. H. A. & Bowden, F. P. (1934). J. Exp. Biol. 11, 409.CrossRefGoogle Scholar