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Genetic analyses of carcass composition, as assessed by X-ray computer tomography, and meat quality traits in Scottish Blackface sheep

  • E. Karamichou (a1), R. I. Richardson (a2), G. R. Nute (a2), K. A. McLean (a3) and S. C. Bishop (a1)...


Genetic parameters for carcass composition and meat quality traits were estimated in Scottish Blackface sheep, previously divergently selected for carcass lean content (LEAN and FAT lines). Computerized X-ray tomography (CT) was used to obtain non-destructive in vivo estimates of the carcass composition of 700 lambs, at ca. 24 weeks of age, with tissue areas and image densities obtained for fat, muscle and bone components of the carcass. Comprehensive measures of meat quality and carcass fatness were made on 350 male lambs, at ca. 8 months of age, which had previously been CT scanned. Meat quality traits included intramuscular fat content, initial and final pH of the meat, colour attributes, shear force, dry matter, moisture and nitrogen proportions, and taste panel assessments of the cooked meat. FAT line animals were significantly (P<0·05) fatter than the LEAN line animals in all measures of fatness (from CT and slaughter data), although the differences were modest and generally proportionately less than 0·1. Correspondingly, the LEAN line animals were superior to the FAT line animals in muscling measurements. Compared with the LEAN line, the FAT line had lower muscle density (as indicated by the relative darkness of the scan image), greater estimated subcutaneous fat (predicted from fat classification score) at slaughter, more intramuscular fat content, a more ‘yellow’ as opposed to ‘red’ muscle colour, and juicer meat (all P<0·05). All CT tissue areas were moderately to highly heritable, with h2 values ranging from 0·23 to 0·76. Likewise, meat quality traits were also moderately heritable. Muscle density was the CT trait most consistently related to meat quality traits, and genetic correlations of muscle density with live weight, fat class, subcutaneous fat score, dry matter proportion, juiciness, flavour and overall liking were all moderately to strongly negative, and significantly different from zero. In addition, intramuscular fat content was positively genetically correlated with juiciness and flavour, and negatively genetically correlated with shear force value. The results of this study demonstrate that altering carcass fatness will simultaneously change muscle density (indicative of changes in intramuscular fatness), and aspects of intramuscular fat content, muscle colour and juiciness. The heritabilities for the meat quality traits indicate ample opportunities for altering most meat quality traits. Moreover, it appears that colour, intramuscular fat content, juiciness, overall liking and flavour may be adequately predicted, both genetically and phenotypically, from measures of muscle density. Thus, genetic improvement of carcass composition and meat quality is feasible using in vivo measurements.


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Association of Official Analytical Chemists. 1997. Official methods of analysis, 16th edition. AOAC, Arlington, VA.
Bishop, S. C. 1993. Selection for predicted carcass lean content in Scottish Blackface sheep. Animal Production 56: 379386.
Cameron, N. D. 1990. Genetic and phenotypic parameters for carcass traits, meat and eating quality traits in pigs. Livestock Production Science 26: 119135.
Campbell, A. W., Bain, W. E., McRae, A. F., Broad, T. E., Johnstone, P. D., Dodds, K. G., Veenvliet, B. A., Greer, G. J., Glass, B. C. and Beattie, A. E. 2003. Bone density in sheep: genetic variation and quantitative trait loci localisation. Bone 33: 540548.
Clutter, A. C. 1995. Molecular genetics and meat quality. National Swine Improvement Federation, Iowa.
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: 8593.
Conington, J., Bishop, S. C., Grundy, B., Waterhouse, A. and Simm, G. 2001. Sustainable, multitrait selection indexes for UK hill sheep. Animal Science 73: 413423.
Cummings, S. R., Black, D. M., Nevitt, M. C., Browner, W. S., Cauley, J. A., Genant, H. K., Mascioli, S. R., Scott, J. C., Seeley, D. G., Steiger, P. and Vogt, T. M. 1990. Appendicular bone-density and age predict hip fracture in women. Jama-Journal of the American Medical Association 263: 665668.
De Boer, H. D., Dumont, B. L., Pomeroy, R. W. and Weniger, J. H. 1974. Manual on EAAP reference methods for the assessment of carcass characteristics in cattle. Livestock Production Science 1: 151164.
Demirel, G., Wachira, A. M., Sinclair, L. A., Wilkinson, R. G., Wood, J. D. and Enser, M. 2004. Effects of dietary n-3 polyunsaturated fatty acids, breed and dietary vitamin E on the fatty acids of lamb muscle, liver and adipose tissue. British Journal of Nutrition 91: 551565.
DeVol, D. L., McKeith, F. K., Bechtel, P. J., Novakofski, J., Shanks, R. D. and Carr, T. R. 1988. Variation in composition and palatability traits and relationships between muscle characteristics and palatability in a random sample of pork carcasses. Journal of Animal Science 66: 385.
Fernandes, T. L., Wilton, J. W., Mandell, I. B. and Devitt, C. J. B. 2002. Genetic parameter estimates for meat quality traits in beef cattle managed under a constant finishing program. Proceedings of the seventh world congress on genetics applied to livestock production, communication no. 293.
Fisher, A. V., Enser, M., Richardson, R. I., Wood, J. D., Nute, G. R., Kurt, E., Sinclair, L. A. and Wilkinson, R. G. 2000. Fatty acid composition and eating quality of lamb types derived from four diverse breed×production systems. Meat Science 55: 141147.
Folch, J., Lees, M. and Stanley, G. H. S. 1957. A simple method for the isolation and purification of lipids from animal tissues. Journal of Biological Chemistry 226: 497509.
GenStat 7 Committee, 2003. Reference manual. Oxford University Press, Oxford.
Gilmour, A. R., Cullis, B. R., Welham, S. J. and Thompon, R. 2004. ASREML: program user manual. NSW, Agriculture, Orange, Australia.
Hermesch, S., Luxford, B. G. and Graser, H. U. 2000. Genetic parameters for lean meat yield, meat quality, reproduction and feed efficiency traits for Australian pigs. 3. Genetic parameters for reproduction traits and genetic correlations with production, carcase and meat quality traits. Livestock Production Science 65: 261270.
Jones, H. E., Lewis, R. M., Young, M. J. and Simm, G. 2004. Genetic parameters for carcass composition and muscularity in sheep measured by X-ray computer tomography, ultrasound and dissection. Livestock Production Science 90: 167179.
Jopson, N. B., McEwan, J. C., Dodds, K. G. and Young, M. J. 1995. Economic benefits of including computer tomography measurements in sheep breeding programmes. Proceedings of Australian Association for Animal Breeding and Genetics 12: 7276.
Just, A., Pedersen, O. K., Jorgensen, H. and Kruse, V. 1986. Heritability estimates of some blood characters and intramuscular fat and their relationship with some production characters in pigs. Pig News and Information 7: 198.
Kempster, A. J., Cook, G. L. and Grantleysmith, 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: 107138.
Kuchtik, J., Subrt, J. and Horak, F. 1996. Quality analysis of meat of slaughter lambs. Zivocisna Vyroba 41: 183188.
Larzul, C., Lefaucheur, L., Ecolan, P., Gogue, J., Talmant, A., Sellier, P., Le Roy, P. and Monin, G. 1997. Phenotypic and genetic parameters for longissimus muscle fiber characteristics in relation to growth, carcass, and meat quality traits in large white pigs. Journal of Animal Science 75: 31263137.
Lewis, R. M., Simm, G. and Warkup, C. C. 1993. Enjoying the taste of lamb. Meat Focus International 2: 393395.
Lo, L. L. 1990. A genetic analysis of growth, real-time ultrasound, carcass and pork quality data in Duroc and Landrace swine. M.Sc. thesis, University of Illinois.
Lo, L. L., McLaren, D. G., McKeith, F. K., Fernando, R. L. and Novakofski, J. 1992. Genetic analyses of growth, real-time ultrasound, carcass, and pork quality traits in Duroc and Landrace pigs. II. Heritabilities and correlations. Journal of Animal Science 70: 23872396.
MacDougall, D. B. and Rhodes, D. N. 1972. Characteristics of appearance of meat. 3. Studies on color of meat from young bulls. Journal of the Science of Food and Agriculture 23: 637647.
McGeehin, B., Sheridan, J. J. and Butler, F. 2001. Factors affecting the pH decline in lamb after slaughter. Meat Science 58: 7984.
Mallows, C. L. 1973. Some comments on Cp. Technometrics 15: 661675.
Malmfors, B. and Nilsson, R. 1979. Meat quality traits in Swedish Landrace and Yorkshire pigs with special emphasis on genetics. Acta Agriculturæ Scandinavica 29: 8190.
Rubino, R., Morand-Fehr, P., Renieri, C., Peraza, C. and Sarti, F. M. 1999. Typical products of the small ruminant sector and the factors affecting their quality. Small Ruminant Research 34: 289302.
Scheper, J. 1979. Influence of environmental and genetic-factors on meat quality. Acta Agriculturæ Scandinavica 29: 2031.
Schworer, D., Morel, P., Prabucki, A. and Rebsamen, A. 1987. Selection for intramuscular fat in pigs. Results of investigations in Switzerland. Deutsche Tierzuechter 39: 392.
Sehested, E. 1984. Computerised tomography in sheep. In In vivo measurement of body composition in meat animals (ed. Lister, D.), pp. 6774, Elsevier, London.
Sellier, P. 1988. Genetics of meat and carcass traits. In The genetics of the pig (ed. Rothschild, M. F. and Ruvinsky, A.), pp. 463510. CAB International, Wallingford.
Simm, G. and Dingwall, W. S. 1989. Selection indices for lean meat production in sheep. Livestock Production Science 21: 223233.
Ward, C. E., Trent, A. and Hildebrand, J. L. 1995. Consumer perception of lamb compared with other meats. Journal of Sheep and Goat Research 11: 6470.
Watanabe, A., Daly, C. C. and Devine, C. E. 1996. The effects of the ultimate pH of meat on tenderness changes during ageing. Meat Science 42: 6778.
Wood, J. D. 1990. Consequences for meat quality of reducing carcass fatness. In Reducing fat in meat animals (ed. Wood, J. D. and Fisher, A. V.), pp. 344397, Elsevier Applied Science, London.
Young, M.J., Garden, K. L., Knopp, T. C. 1987. Computer aided tomography-comprehensive body compositional data from live animals. Proceedings of the New Zealand Society of Animal Production, vol. 47, pp. 6971.
Young, M. J., Lewis, R. M., McLean, K. A., Robson, N. A. A., Fraser, J., Fitzsimons, J., Donbavand, J. and Simm, G. 1999. Prediction of carcass composition in meat breeds of sheep using computer tomography. Proceedings of the British Society of Animal Science 1999 pp. 43.
Young, M. J., Logan, C. M., Beatson, P. R., Nsoso, S. J. 1996. Prediction of carcass tissue weight in vivo using live weight, ultrasound or X-ray CT measurements. Proceedings of the New Zealand Society of Animal Production, vol. 56, pp. 205211.
Young, M. J., Reid, D. H. and Scales, G. H. 1993. Effects of breed and ultimate pH on the odour and flavour of sheep meat. New Zealand Journal of Agricultural Research 36: 363370.


Genetic analyses of carcass composition, as assessed by X-ray computer tomography, and meat quality traits in Scottish Blackface sheep

  • E. Karamichou (a1), R. I. Richardson (a2), G. R. Nute (a2), K. A. McLean (a3) and S. C. Bishop (a1)...


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