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Responses to selection for lean growth in sheep

Published online by Cambridge University Press:  18 August 2016

G. Simm ,
R.M. Lewis ,
B. Grundy  and
W.S. Dingwall
G. Simm*
Affiliation:
Animal Biology Division, Scottish Agricultural College, West Mains Road, Edinburgh EH9 3JG, UK
R.M. Lewis
Affiliation:
Animal Biology Division, Scottish Agricultural College, West Mains Road, Edinburgh EH9 3JG, UK
B. Grundy
Affiliation:
Animal Biology Division, Scottish Agricultural College, West Mains Road, Edinburgh EH9 3JG, UK
W.S. Dingwall
Affiliation:
Animal Biology Division, Scottish Agricultural College, West Mains Road, Edinburgh EH9 3JG, UK
*
†E-mail:g.simm@ed.sac.ac.uk
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Abstract

This paper reports the selection responses achieved, and related results, following 9 years of index selection for lean growth in Suffolk sheep. The breeding goal of the index used comprised carcass lean weight and carcass fat weight at a constant age, with relative economic values of + 3 and –1 per kg. The selection criteria were live weight (LWT), ultrasonic fat depth (UFD) and ultrasonic muscle depth (UMD) adjusted to a constant age of 150 days. By year 9, responses in LWT, UFD and UMD in both sexes, as judged by the divergence between selection and control line performance, amounted to 4·88 kg, -1·1 mm and 2·8 mm respectively; these responses are between 7 and 15% of the overall means of the traits concerned. Although selection was originally on index scores based on phenotypic records, the retrospective analyses reported here used the mixed model applications of residual maximum likelihood to estimate parameters and best linear unbiased prediction to predict breeding values. The statistical model comprised fixed effects plus random effects accounting for direct additive, maternal additive and temporary environmental variation. Estimated genetic trends obtained by regressing estimated breeding values on year of birth were similar to annual responses estimated by comparing selection and control line means. Estimates of direct heritabilities were 0·054, 0·177, 0·286, 0·561 and 0·410 for birth weight (BWT), weaning weight (WWT), LWT, UFD and UMD respectively. Corresponding estimates of maternal heritabilities were 0·287, 0·205, 0·160, 0·083 and 0·164. Phenotypic correlations between all pairs of traits were positive and usually moderately high. There were low negative direct additive correlations between BWT and WWT, and between BWT and LWT, but higher positive maternal additive correlations between all other pairs of weight traits.

Keywords

selection responsessheepultrasonography
Type
Breeding and genetics
Information
Animal Science , Volume 74 , Issue 1 , February 2002 , pp. 39 - 50
Copyright
Copyright © British Society of Animal Science 2002

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References

Banks, R. G. 1999. Genetics of lamb and meat production. In The genetics of sheep (ed. Piper, L. and Ruvinsky, A.), pp. 505–522. CAB International, Wallingford.Google Scholar
Bennett, G. L. 1990. Selection for growth and carcass composition in sheep. Proceedings of the fourth world congress on genetics applied to livestock production, Edinburgh, vol. XV, pp. 27–36.Google Scholar
Bennett, G. L., Meyer, H. H. and Kirton, A. H. 1988. Effects of selection for divergent ultrasonic fat depth in rams on progeny fatness. Animal Production 47: 379–386.Google Scholar
Bishop, S. C. 1993. Selection for predicted carcass lean content in Scottish Blackface sheep. Animal Production 56: 379–386.Google Scholar
Cameron, N. D. and Bracken, J. 1992. Selection for carcass lean content in a terminal sire breed of sheep. Animal Production 54: 367–377.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
Dingwall, W. S., McKelvey, W. A. C., Mylne, M. J. A. and Simm, G. 1994. A protocol for MOET in Suffolk sheep. Programme and abstracts of the 45th annual meeting of the European Association for Animal Production, Edinburgh, p. 256 (abstr. ).Google Scholar
Dingwall, W. S., McKelvey, W. A. C., Mylne, J. and Simm, G. 1993. An evaluation of MOET in Suffolk sheep. Animal Production 56: 444 (abstr. ).Google Scholar
Fogarty, N. M. 1995. Genetic parameters for liveweight, fat and muscle measurements, wool production and reproduction in sheep: a review. Animal Breeding Abstracts 63: 101–143. $$(Also, see Erratum preceding p. 935, vol. 63. )Google Scholar
Genstat 5 Committee. 1993. Genstat 5 release 3 reference manual. Oxford University Press, Oxford.Google Scholar
Gilmour, A. R. 1996. ASREML, a spatial REML program. NSW Agriculture, Orange, Australia.Google Scholar
Gilmour, A. R., Thompson, R. and Cullis, B. R. 1995. Average information REML, an efficient algorithm for variance estimation in linear mixed models. Biometrics 51: 1440–1450.Google Scholar
Henderson, C. R. 1988. Theoretical basis and computational methods for a number of different animal models. Journal of Dairy Science 71: (suppl. ) 1–16.CrossRefGoogle Scholar
Kadim, I. T., Purchas, R. W., Rae, A. L. and Barton, R. A. 1989. Carcass characteristics of Southdown rams from high and low backfat selection lines. New Zealand Journal of Agricultural Research 32: 181–191.Google Scholar
Kempster, A.J. 1983. Carcass quality and its measurement in sheep. In Sheep production (ed. Haresign, W.), pp. 59–74. Butterworths, London.Google Scholar
Kempster, A. J., Croston, D., Guy, D. R. and Jones, D. W. 1987. Growth and carcass characteristics of crossbred lambs by ten sire breeds, compared at the same estimated subcutaneous fat proportion. Animal Production 44: 83–98.Google Scholar
Lewis, R.-M. and Beatson, P. R. 1999. Choosing maternal-effect models to estimate (co)variances for live and fleece weight in New Zealand Coopworth sheep. Livestock Production Science 58: 137–150.Google Scholar
Lewis, R. M., Emmans, G. C., Simm, G., Dingwall, W. S., FitzSimons, J., Fraser, J. C. and Donbavand, J. E. 1999. The consequences of index selection on carcass composition in Suffolk sheep. Proceedings of the British Society of Animal Science, 1999, p. 46.Google Scholar
Lewis, R. M., Simm, G., Dingwall, W. S. and Murphy, S. V. 1996. Selection for lean growth in terminal sire sheep to produce leaner crossbred progeny. Animal Science 63: 133–142.Google Scholar
Leymaster, K. A. and Jenkins, T. G. 1993. Comparison of Texel-and Suffolk-sired crossbred lambs for survival, growth and compositional traits. Journal of Animal Science 71: 859–869.Google Scholar
Lord, E. A., Fennessy, P. F. and Littlejohn, R. P. 1988. Comparison of genotype and nutritional effects on body and carcass characteristics of lambs. New Zealand Journal of Agricultural Research 31: 13–19.Google Scholar
McClelland, T. H., Bonaiti, B. and Taylor, St C.S. 1976. Breed differences in body composition of equally mature sheep. Animal Production 23: 281–293.Google Scholar
McEwan, J. C., Fennessy, P. F., Greer, G. J., Bain, W. E. and Bruce, G. D. 1990. Effects of selection for ultrasonic backfat depth on carcass growth and composition in sheep. Proceedings of the Australian Association of Animal Breeding and Genetics 8: 323–326.Google Scholar
McEwan, J. C., Fennessy, P. F., Greer, G. J., Bruce, G. D. and Bain, W. E. 1989. Selection for carcass composition: effects on the development of subcutaneous and internal fat depots. Proceedings of the Nutrition Society of New Zealand 14: 163–164.Google Scholar
Meat and Livestock Commission. 1999. Sheep yearbook 1999. Meat and Livestock Commission, PO Box 44, Winterhill House, Snowdon Drive, Milton Keynes, MK6 1AX.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
More O’Ferrall, G. J. and Timon, Y. M. 1977. A comparison of eight sire breeds for lamb production. 1. Lamb growth and carcass measurements. Irish Journal of Agricultural Research 16: 267–275.Google Scholar
Morris, C. A., McEwan, J. C., Fennessy, P. F., Bain, W. E., Greer, G. J. and Hickey, S. M. 1997. Selection for high or low backfat depth in Coopworth sheep: juvenile traits. Animal Science 65: 93–103.Google Scholar
Nsoso, S. J. 1995. Genetic control of lean tissue growth rate in sheep: genetic parameters and responses to selection. Ph.D. thesis, Lincoln University, New Zealand.Google Scholar
Patterson, H. D. and Thompson, R. 1971. Recovery of interblock information when block sizes are unequal. Biometrica 58: 454–544.Google Scholar
Simm, G. 1987. Carcass evaluation in sheep breeding programmes. In New techniques in sheep production (ed. Marai, I.F.M. and Owen, J. B.), pp. 125–144. Butterworths, London.Google Scholar
Simm, G. 1992. Selection for lean meat production in sheep. In Progress in sheep and goat research (ed. Speedy, A. W.), pp. 193–215. CAB International, Wallingford.Google Scholar
Simm, G. 1994. Developments in improvement of meat sheep. Proceedings of the fifth world congress on genetics applied to livestock production, Guelph, vol. 18, pp. 3–10.Google Scholar
Simm, G. and Dingwall, W. S. 1989. Selection indices for lean meat production in sheep. Livestock Production Science 21: 223–233.Google Scholar
Simm, G., Lewis, R. M., Collins, J. E. and Nieuwhof, G. J. 2001. Use of sire referencing schemes to select for improved carcass composition in sheep. Journal of Animal Science In press.Google Scholar
Simm, G. and Murphy, S. V. 1996. The effects of selection for lean growth in Suffolk sires on the saleable meat yield of their crossbred progeny. Animal Science 62: 255–263.CrossRefGoogle Scholar
Simm, G., Young, M. J. and Beatson, P. R. 1987. An economic selection index for lean meat production in New Zealand sheep. Animal Production 45: 465–475.Google Scholar
Solis-Ramirez, J., Blair, H. T. and Purchas, R. W. 1993. Direct and correlated responses to selection for high or low ultrasonic backfat depth in Southdown sheep. New Zealand Journal of Agricultural Research 36: 133–141.CrossRefGoogle Scholar
Taylor, St C. S. 1980. Genetic size-scaling rules in animal growth. Animal Production 30: 161–165.Google Scholar
Wolf, B. T., Smith, C., King, J. W. B. and Nicholson, D. 1981. Genetic parameters of growth and carcass composition in crossbred lambs. Animal Production 32: 1–7.Google Scholar
Wolf, B. T., Smith, C. and Sales, D. I. 1980. Growth and carcass composition in the crossbred progeny of six terminal sire breeds of sheep. Animal Production 31: 307–313.Google Scholar
Woodward, J. and Wheelock, V. 1990. Consumer attitudes to fat in meat. In Reducing fat in meat animals (ed. Wood, J. D. and Fisher, A. V.), pp. 66–100. Elsevier, London.Google Scholar