Hostname: page-component-848d4c4894-jbqgn Total loading time: 0 Render date: 2024-07-05T14:37:48.973Z Has data issue: false hasContentIssue false
  • English
  • Français

Induction of lambing every eight months in two breeds of sheep by light control with or without hormonal treatment

Published online by Cambridge University Press:  02 September 2010

J. A. Vesely
J. A. Vesely
Affiliation:
Research Station, Agriculture Canada, Lethbridge, Alberta, Canada TU 4B1
Get access

Summary

Suffolk and Rambouillet female sheep (ewes) were kept in pens where daylight was gradually reduced and were treated, or not treated, with hormones to obtain four lambing cycles in 2·5 years. Oestrus in May, June and July was induced more easily (P<0·01) in Rambouillet than the Suffolk ewes. The advantage of higher conception rates in the Rambouillet ewes during anoestrus was offset by the higher prolificacy rates in the Suffolk in the other three lambing cycles. On average, each breed produced 128 lambs per 100 ewes exposed per lambing cycle. This corresponds to 5·1 lambs per ewe in four lambings, which is equivalent to 2·04 lambs per ewe per year. Under the conditions of the experiment, the addition of Syncro-Mate pessaries (20 mg fluorogestone acetate) and pregnant mare serum gonadotrophin (PMSG, 5 ml/ewe, 50 IU/ml) to the treatment of reduced daylight did not affect the ovulation or conception rates.

Type
Research Article
Information
Animal Production , Volume 21 , Issue 2 , October 1975 , pp. 165 - 174
Copyright
Copyright © British Society of Animal Science 1975

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

Brunner, M. A., Hansel, W. and Hogue, D. E. 1964. Use of 6-methyl-acetoxyprogesterone and pregnant mare serum to induce and synchronize estrus in ewes. J. Anim. Sci. 23: 32–36.Google Scholar
Curl, S. E., Nix, L. and Hudson, F. A. 1968. Lambing rate as influenced by hormoneinduced superovulation in ewes prior to mating. J. Anim. Sci. 27: 431–433.Google Scholar
Dermody, W. C, Foote, W. C. and Hulet, C. V. 1970. Effects of season and progesterone synchronization on ovulation rate in mature western range ewes. J. Anim. Sci. 30: 214–218.CrossRefGoogle ScholarPubMed
Ducker, M. J. and Bowman, J. C. 1970a. Photoperiodism in the ewe. 3. The effects of various patterns of increasing daylength on the onset of anoestrus in Clun Forest ewes. Anim. Prod. 12: 465–471.Google Scholar
Ducker, M. J. and Bowman, J. C. 1970b. Photoperiodism in the ewe. 4. A note on the effect on onset of oestrus in Clun Forest ewes of applying the same decrease in daylight at two different times of the year. Anim. Prod. 12: 513–516.Google Scholar
Ducker, M. J. and Bowman, J. C. 1972. Photoperiodism in the ewe. 5. An attempt to induce sheep of three breeds to lamb every eight months by artificial daylength changes in a non-light-proofed building. Anim. Prod. 14: 323–334.Google Scholar
Ducker, M. J., Thwaites, C. J. and Bowman, J. C. 1970. Photoperiodism in the ewe. 2. The effects of various patterns of decreasing daylength on the onset of oestrus in Clun Forest ewes. Anim. Prod. 12: 115–123.Google Scholar
Hafez, E. S. E. 1952. Studies on the breeding season and reproduction of the ewe. J. agric. Sci., Camb. 42: 189–265.Google Scholar
Hulet, C. V. and Foote, W. C. 1967. Physiological factors affecting frequency and rate of lambing. J. Anim. Sci. 26: 553–562.CrossRefGoogle ScholarPubMed
Mauleon, P. and Rougeot, J. 1962. Regulation des saisons sexuelles chez des brebis de races differentes au moyen de divers rythmes lumineux. Annls Biol. anim. Biochim. Biophys. 2: 209–222.CrossRefGoogle Scholar
Whiteman, J. V., Zollinger, W. A., Thrift, F. A. and Gould, M. B. 1972. Postpartum ating performance of ewes involved in a twice-yearly lambing program. J. Anim. Sci. 35: 836–842.Google Scholar
Wiltbank, J. M., Zimmerman, D. R., Ingalls, J. E. and Rowden, N. W. 1965. Use of progestational compounds alone or in combination with estrogen for synchronization of estrus. J. Anim. Sci. 24: 990–994.CrossRefGoogle Scholar
Yeates, N. T. M. 1949. The breeding season of sheep with particular reference to its modification by artificial means using light. J. agric. Sci., Camb. 39: 1–42.Google Scholar