Hostname: page-component-cd9895bd7-mkpzs Total loading time: 0 Render date: 2024-12-27T03:22:24.314Z Has data issue: false hasContentIssue false
  • English
  • Français

Genetic analysis of live weight and ultrasonic fat and muscle traits in a hill sheep flock undergoing breed improvement utilizing an embryo transfer programme

Published online by Cambridge University Press:  18 August 2016

J. A. Roden ,
B. G. Merrell ,
W. A. Murray  and
W. Haresign
J. A. Roden*
Affiliation:
Institute of Rural Studies, University of Wales Aberystwyth, Llanbadarn Campus, Aberystwyth SY23 3AL, UK
B. G. Merrell
Affiliation:
ADAS Redesdale, Rochester, Otterburn, Newcastle on Tyne NE19 1SB, UK
W. A. Murray
Affiliation:
ADAS Redesdale, Rochester, Otterburn, Newcastle on Tyne NE19 1SB, UK
W. Haresign
Affiliation:
Institute of Rural Studies, University of Wales Aberystwyth, Llanbadarn Campus, Aberystwyth SY23 3AL, UK
*
†E-mail:[email protected]
Get access

Abstract

Genetic parameters for pre-weaning live weights and ultrasonic scanning measurements were estimated from a flock of Scottish Blackface sheep undergoing an embryo transfer programme. Maternal environmental effects could be evaluated without confounding with maternal genetic effects because embryos were transferred to unrelated recipient ewes. The data for the study were collected over a 7-year period (1993-1999) and related to a conventional hill farming system. The data were from 1465 lambs, the progeny of 60 sires, 263 donors and 784 recipient ewes. The only exception to the conventional farming system was at mating time when embryos were collected from selected donor ewes, following superovulation, and transferred to unrelated recipient ewes. Maternal environmental effects were important for birth weight (BW), 4-week weight (W4) and weaning weight (WW) but of less importance for ultrasonic fat depth (UFD), muscle depth (UMD) and muscle width (UMW). The heritabilities of the pre-weaning weights were moderate (0·17 to 0·23). The heritabilities of UFD and UMD were 0·44 and 0·27 respectively and were higher than found in previous similar studies. The heritability of UMW was low, 0·06. The genetic and phenotypic correlations among the pre-weaning weight traits were positive and moderate. There was a positive genetic ( + 0·25) and phenotypic ( + 0·24) correlation between UFD and UMD. The phenotypic and genetic correlations between BW and W4 and the scanning traits (UFD, UMD and UMW) were close to zero, and the correlations of WW with UFD, UMD and UMW were positive. The results of this study clearly demonstrate the importance of maternal environmental effects for lamb weights up to weaning and also suggest that genetic improvement for carcass composition in some populations of extensively reared hill sheep could be achieved more rapidly than previously thought possible.

Keywords

embryo transfergenetic parameterslive weightsheepultrasonic measurements
Type
Breeding and genetics
Information
Animal Science , Volume 76 , Issue 3 , June 2003 , pp. 367 - 373
Copyright
Copyright © British Society of Animal Science 2003

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

Atkins, K. D. 1986. A genetic analysis of the components of lifetime productivity in Scottish Blackface sheep. Animal Production 43: 405–419.Google Scholar
Bari, F. Y., Khalid, M., Haresign, W., Merrell, B., Murray, A. and Richards, R. I. W. 1999. An evaluation of the success of MOET in breeds of hill sheep maintained under normal systems of hill flock management. Animal Science 69: 367–376.Google Scholar
Bari, F. Y., Khalid, M., Haresign, W., Murray, A. and Murray, B. 2000. Effect of mating system, flushing procedure, progesterone dose and donor ewe age on the yield and quality of embryos within a MOET programme in sheep. Theriogenology 53: 727–742.CrossRefGoogle ScholarPubMed
Bishop, S. C., Conington, J., Waterhouse, A. and Simm, G. 1996. Genotype ✕ environment interactions for early growth and ultrasonic measurements in hill sheep. Animal Science 62: 271–277.Google Scholar
Conington, J., Bishop, S. C., Waterhouse, A. and Simm, G. 1995. A genetic analysis of early growth and ultrasonic measurements in hill sheep. Animal Science 61: 85–93.Google Scholar
Conington, J., Bishop, S. C., Waterhouse, A. and Simm, G. 1998. A comparison of growth and carcass traits in Scottish Blackface lambs sired by genetically lean or fat rams. Animal Science 67: 299–309.Google Scholar
Fogarty, N. M. 1995. Genetic parameters for live weight, fat and muscle measurements, wool production and reproduction in sheep: a review. Animal Breeding Abstracts 63: 101–143.Google Scholar
Genstat 5 Committee. 1993. Reference manual. Oxford University Press, Oxford.Google Scholar
Gilmour, A. R., Cullis, B. W., Wellham, S. J. and Thompson, R. 1999. ASREML: program user manual. NSW Agriculture, Orange, Australia.Google Scholar
Meat and Livestock Commission. 1998. Sheep yearbook 1998. Meat and Livestock Commission, Milton Keynes, UK.Google Scholar
Mercer, J. T., Brotherstone, S., Bradfield, M. J. and Guy, D. R. 1994. Estimation of genetic parameters for use in sheep sire referencing schemes. Proceedings of the fifth world congress on genetics applied to livestock production, Guelph, vol. 18, pp. 39–42.Google Scholar
Saatci, M., Ap Dewi, I. and Ulutas, Z. 1998. Correlations between weaning weight, carcass traits and ultrasonic body measurements in Welsh Mountain sheep. Proceedings of the British Society of Animal Science, 1998, p. 84.CrossRefGoogle Scholar
Saatci, M., Ap Dewi, I. and Ulutas, Z. 1999. Variance components due to direct and maternal effects and estimation of breeding values for 12-week weight of Welsh Mountain lambs. Animal Science 69: 345–352.Google Scholar
Thorsteinsson, S. and Eythorsdottir, E. 1998. Genetic parameters of ultrasonic and carcass cross-sectional measurements and muscle and fat weight of Icelandic lambs. Proceedings of the sixth world congress on genetics applied to livestock production, Armidale, vol. 24, pp. 149–152.Google Scholar