Hostname: page-component-7479d7b7d-rvbq7 Total loading time: 0 Render date: 2024-07-13T08:49:08.788Z Has data issue: false hasContentIssue false
  • English
  • Français

Use of embryo transfer in genetic improvement of sheep

Published online by Cambridge University Press:  02 September 2010

C. Smith
C. Smith
Affiliation:
AFRC Animal Breeding Research Organisation, West Mains Road, Edinburgh EH9 3JQ
Get access

Abstract

Embryo transfer following multiple ovulation could allow faster rates of genetic change in sheep, by increasing the effective female reproductive rate. The gains would come from lower generation intervals or increased selection among females, or both. They require good embryo transfer rates at 6 to 8 months of age. These are not adequate at present and need to be improved by research and development, justified by the extra genetic gains shown here to be possible. If high rates of embryo transfer (10 progeny per donor) could be achieved, then, with appropriate selection schemes, the rates of genetic change could be doubled compared with efficient schemes using normal reproduction. This applies to most traits, to those measured before reproductive age (growth traits and carcass traits estimated in the live animal), to female reproductive traits and to wool traits measured at 14 to 16 months of age. With moderate rates of embryo transfer (5 progeny per donor), gains of 50 to 70% in genetic response could be obtained. To limit the rate of inbreeding to moderate levels in a closed selection flock, some 100 to 200 females (1000 progeny) would be required. Application of the methods may be difficult with current breeding structures, and the development of special nucleus selection stocks i s proposed.

Type
Research Article
Information
Animal Production , Volume 42 , Issue 1 , February 1986 , pp. 81 - 88
Copyright
Copyright © British Society of Animal Science 1986

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

Armstrong, D. T. and Evans, G. 1983. Factors affecting success of embryo transfer in sheep and goats. Theriogenology 19: 31–42.Google Scholar
Bulmer, M. G. 1971. The effect of selection on genetic variability. Am. Nat. 105: 201–211.Google Scholar
Falconer, D. S. 1981. Introduction to Quantitative Genetics. 2nd ed. Longman, London.Google Scholar
Hanrahan, J. P. and Quirke, J. F. 1982. Selection on ovulation rate in sheep aided by the use of superovulation and egg transfer. In Proc. Wld Congr. Sheep and Beef Cattle Breeding. Vol. II. (ed. Barton, R. A. and Smith, W. C.), pp. 329–335. Dunsmore Press, Palmerston North, NZ.Google Scholar
Land, R. B. and Hill, W. G. 1975. The possible use of superovulation and embryo transfer in cattle to increase response to selection. Anim. Prod. 21: 1–12.Google Scholar
Martin, T. G. and Smith, C. 1980. Studies on a selection index for improvement of litter weight in sheep. Anim. Prod. 31: 81–85.Google Scholar
Moore, N. W. 1982. Egg transfer in the sheep and goat. In Mammalian Egg Transfer (ed. Adams, C. E.), pp. 119–133. CRC Press, Boca Raton, Florida.Google Scholar
Nicholas, F. W. and Smith, C. 1983. Increased rates of genetic change in dairy cattle by embryo transfer and splitting. Anim. Prod. 36: 341–353.Google Scholar
Quirke, J. F. and Hanrahan, J. P. 1977. Comparison of the survival in the uteri of adult ewes of cleaved ova from adult ewes and ewe lambs. J. Reprod. Fert. 51: 487–489.CrossRefGoogle ScholarPubMed
Sehested, E. 1984. Evaluation of carcass composition of live lambs based on computed tomography. 35th Meet. Eur. Ass. Anim. Prod., The Hague, Netherlands.Google Scholar
Smith, C. 1978. The effect of inflation and form of investment on the estimated value of genetic improvement in farm livestock. Anim. Prod. 26: 101–110.Google Scholar
Smith, C. 1981. Levels of investment in testing the genetic improvement of livestock. Livest. Prod. Sci. 8: 193–201.CrossRefGoogle Scholar
Smith, C. 1984. Rates of genetic change in farm livestock. Res. Dev. Agric. 1: 79–85.Google Scholar
Walkley, J. R. W. and Smith, C. 1980. The use of physiological traits in genetic selection for litter size in sheep. J. Reprod. Fert. 59: 83–88.CrossRefGoogle ScholarPubMed