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Genetic parameters of lamb carcass characteristics at three end-points: fat level, age and weight

Published online by Cambridge University Press:  02 September 2010

G. E. Pollott ,
D. R. Guy  and
D. Croston
G. E. Pollott
Affiliation:
Wye College — University of London, Ashford, Kent TN25 5AH
D. R. Guy
Affiliation:
Meat and Livestock Commission, PO Box 44, Winterkill House, Snowdon Drive, Milton Keynes MK6 1AX
D. Croston
Affiliation:
Meat and Livestock Commission, PO Box 44, Winterkill House, Snowdon Drive, Milton Keynes MK6 1AX
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Abstract

Although breed substitution is a very common method of rapidly altering the characteristics of a livestock population, within-breed selection for lamb carcass characters is becoming more widely used in the terminal sire breeds in Britain. Such selection schemes require accurate and applicable genetic parameters for the carcass traits of interest. This paper reports a genetic analysis of 11 traits measured on 3592 lamb carcasses using a derivative-free restricted maximum likelihood technique. Because of the trial design it was possible to estimate the genetic parameters of the traits at comparable fat cover, carcass weight and age at slaughter, using appropriate within-subclass covariates.

Heritability estimates for muscle depth (0·23, s.e. 0·04), muscle width (0·32, s.e. 0·05), fat depth (0·31, s.e. 0·05), caliper fat (0·23, s.e. 0·04) and conformation (0·29, s.e. 0·05) were similar in the weight and age-corrected results. Heritabilities for fat cover (0·35, s.e. 0·05), daily carcass weight gain (0·63, s.e. 0·07), and leg conformation (0·44, s.e. 0·05) were higher with slaughter at fixed weight than at fixed age. The heritabilities of traits at comparable fat cover were similar to those at comparable age at slaughter with the exception of daily carcass weight gain, fat depth, caliper fat and leg conformation.

The different measures of fat were highly correlated with each other. Conformation was moderately correlated with external fat score, carcass length and muscle depth. Muscle depth was moderately correlated with carcass length. Differences were found between genetic correlations calculated at equal weight, a common point of comparison in breeding schemes, and equal fat cover, a common end-point for slaughter lambs.

Keywords

carcass compositiongenetic parameterssheep
Type
Research Article
Information
Animal Production , Volume 58 , Issue 1 , February 1994 , pp. 65 - 75
Copyright
Copyright © British Society of Animal Science 1994

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References

Afifi, A. A. and Clark, V. 1990. Computer-aided multivariate analysis. Van Nostrand Reinhold, New York.Google Scholar
Bennett, G. L., Johnson, D. L., Kirton, A. H. and Carter, A. H. 1991. Genetic and environmental effects on carcass characteristics of Southdown × Romney lambs. 2. Genetic and phenotypic variation. Journal of Animal Science 69: 1864–1874.CrossRefGoogle ScholarPubMed
Botkin, M. P., Field, R. A., Riley, M. L., Nolan, J. C. and Roehrkasse, G. P. 1969. Heritability of carcass traits in lambs. journal of Animal Science 29: 251–255.CrossRefGoogle Scholar
Bouix, J., Bebe, B., Lefevre, C. and Eycheme, F. 1986. Variabilite genetique entre et intra-race de la croissance et des qualites de carcases d'agneaux. Journees de la recherche. INRA, ITOVIC, Paris.Google Scholar
Bowman, J. C. and Hendy, C. R. C. 1972. Study of retail requirements and genetic parameters of carcass quality in polled Dorset Horn sheep. Animal Production 14: 189–198.Google Scholar
Bowman, J. C., Marshall, J. E. and Broadbent, J. S. 1968. Genetic parameters of carcass quality in Down cross sheep. Animal Production 10: 183–191.Google Scholar
Brown, W. R. 1989. A comparison of carcass compositions of lambs from Suffolk sires selected for high and low lean growth index. B.Sc. thesis, University of Edinburgh.Google Scholar
Cameron, N. D. 1992. Correlated responses in slaughter and carcass traits of crossbred progeny to selection for carcass lean content in sheep. Animal Production 54: 379–388.Google Scholar
Cotterill, P. D. and Roberts, E. M. 1976. Preliminary heritability estimates of some lamb carcass traits. Proceedings of the Australian Society of Animal Production 11: 53–56.Google Scholar
Croston, D., Kempster, A. J., Guy, D. R. and Jones, D. W. 1987. Carcass composition of crossbred lambs by ten sire breeds compared at the same carcass subcutaneous fat proportion. Animal Production 44: 99–106.Google Scholar
El Karim, A. I. A. and Owen, J. B. 1987. Post-weaning growth performance, carcass characteristics and preliminary heritability estimates for some carcase traits of two types of Sudan Desert sheep on intensive feeding. journal of Agricultural Science, Cambridge 109: 531–538.CrossRefGoogle Scholar
Falconer, D. S. 1989. Introduction to quantitative genetics. Longman, London.Google Scholar
Hayes, J. F. and Hill, W. G. 1980. A reparameterization of a genetic selection index to locate its sampling properties. Biometrics 36: 237–248.CrossRefGoogle ScholarPubMed
Kempster, A. J., Cook, G. L. and Grantley-Smith, M. 1986. National estimates of the body composition of British cattle, sheep and pigs with special reference to trends in fatness: a review. Meat Science 17: 107–138.CrossRefGoogle ScholarPubMed
Kempster, A. J., Croston, D., Guy, D. R. and Jones, D. W. 1987b. Growth and carcass characteristics of crossbred lambs by ten sire breeds, compared at the same estimated carcass subcutaneous fat proportion. Animal Production 44: 83–98.Google Scholar
Kempster, A. J., Croston, D. and Jones, D. W. 1987a. Tissue growth and development in crossbred lambs sired by ten breeds. Livestock Production Science 16: 145–162.CrossRefGoogle 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
Meat and Livestock Commission. 1974a. Planned crossbreeding and lamb carcase weights. Meat and Livestock Commission, Milton Keynes.Google Scholar
Meat and Livestock Commission. 1974b. Standard conditions of deadweight purchase for cattle, sheep, pork and cutter pigs. Meat and Livestock Commission, Milton Keynes.Google Scholar
Meyer, K. 1989. Restricted maximum likelihood to estimate variance components for animal models with several random effects using a derivative-free algorithm. Genetique, Selection et Evolution 21: 317–340.CrossRefGoogle Scholar
Parratt, A. C., Burt, C. M., Bennett, G. L., Clarke, J. J., Kirton, A. H. and Rae, A. L. 1987. Heritabilities, genetic and phenotypic correlations for carcase traits and ultrasonic fat depth in sheep. Proceedings of the sixth conference, Australian Association of Animal Breeding and Genetics, University of Western Australia, Perth.Google Scholar
Schrooten, C. and Visscher, A. H. 1987. [Genetic parameters of growth and carcass quality in Texel sheep.] Animal Breeding Abstracts 56: 1149.Google Scholar
Shrestha, J. N. B., Fortin, A. and Heaney, D. P. 1986. Genetic and phenotypic parameters of carcass traits in ram lambs reared artificially in a controlled environment. Canadian journal of Animal Science 66: 905–914.CrossRefGoogle Scholar
Simm, G. and Dingwall, W. S. 1989. Selection indices for lean meat production in sheep. Livestock Production Science 21: 223–233.CrossRefGoogle Scholar
Smith, S. P. and Graser, H. U. 1986. Estimating variance components in a class of mixed models by restricted maximum likelihood. Journal of Dairy Science 69: 1156–1165.CrossRefGoogle Scholar
Thorsteinsson, S. S. and Bjornsson, H. 1982. Genetic studies on carcass traits in Icelandic twin ram lambs. I. Estimates of genetic parameters on carcass traits, liveweight at weaning and carcass weight. Livestock Production Science 8: 489–505.CrossRefGoogle Scholar
Waldron, D. F., Thomas, D. L., Stookey, J. M., Nash, T. G., McKeith, F. K. and Fernando, R. L. 1990. Central ram tests in the mid-western United States. 3. Relationship between sire's central test performance and progeny performance. journal of Animal Science 68: 45–53.Google Scholar
Wolf, B. T., Smith, C, King, J. W. B. and Nicholson, D. 1981. Genetic parameters of growth and carcass composition in cross-bred lambs. Animal Production 32: 1–7.Google Scholar
Wolf, B. T., Smith, C. and Sales, D. I. 1980. Growth and carcass composition in the cross-bred progeny of six terminal sire breeds of sheep. Animal Production 31: 307–313.Google Scholar