Hostname: page-component-586b7cd67f-dsjbd Total loading time: 0 Render date: 2024-11-23T01:55:06.282Z Has data issue: false hasContentIssue false
  • English
  • Français

Carcass composition, conformation and muscularity in Texel lambs of different breeding history, sex and leg shape score

Published online by Cambridge University Press:  18 August 2016

B. T. Wolf ,
D. A. Jones  and
M. G. Owen
B. T. Wolf
Affiliation:
Welsh Institute of Rural Studies, University of Wales Aberystwyth, Llanbadarn Campus, Aberystwyth SY23 3AL, UK
D. A. Jones
Affiliation:
Meat and Livestock Commission, PO Box 44, Winterhill House, Snowdon Drive, Milton Keynes MK6 1AX, UK
M. G. Owen
Affiliation:
Meat and Livestock Commission, PO Box 44, Winterhill House, Snowdon Drive, Milton Keynes MK6 1AX, UK
Get access

Abstract

This study investigated the effects of flock, sex and leg shape scores (assessed in the live animal) on the carcass yield, conformation and composition of purebred Texel lambs. Two flocks were managed in a common environment. The first (Lean Index flock) had a 6-year history of selection for lean tissue growth rate using an index of live weight and ultrasonic muscle and fat depths measured at 20 weeks of age. The second (Conformation flock) had recently been established by mating rams of extreme conformation selected from the UK Texel population with ewes in the Lean Index flock. Lambs were evaluated at a mean age of 139 days at the end of an 11-week performance test in which they were reared indoors on a concentrate diet. Prior to slaughter, the lambs were assessed for conformation of the hind leg (leg shape score). Mean live weights and ultrasonic fat depths did not differ significantly between flocks or leg shape scores but ultrasonic muscle depths were highest in the high leg shape score (27·9, 27·7 and 30·1 mm in low, medium and high scores, s.e.d. 0·55). At constant slaughter weight, the lean weight in the side was 0·4 kg higher in the Conformation flock and 0·3 kg higher in lambs of high v. low leg shape score (P < 0·001) with no significant differences in other tissue weights. Consequently, lean: bone ratio and lean proportions in both the live weight and carcass were higher in the Conformation flock and in lambs of high leg shape score. Lambs of high leg shape score had better carcass conformation scores (14·1, 12·9 and 11·9, for high, medium and low scores respectively, s.e.d. 0·30), shorter side length and higher values for all muscularity traits. Lean tissue distribution in major joints and individual muscles did not differ between flocks but the mean proportion of total lean in the higher priced cuts was higher (553·1 v. 543·9 g/kg, s.e.d. 3·26) for lambs of high v. low leg shape score. Males were 6·5 kg heavier than females at scanning (P < 0·001), had lower ultrasonic fat depths (2·8 v. 3·2 mm; P < 0·01) but did not differ in ultrasonic muscle depths. At equal slaughter age, males produced 1 kg more lean tissue and had a higher proportion of lean in the side than females (665·2 v. 638·9 g/kg) but did not differ in lean proportion in the live weight, carcass conformation and muscularity scores. Females carried a higher proportion of total lean in the higher priced cuts (555·6 v. 541·8 g/kg; P < 0·01) and in some individual muscles. It was concluded that there is important variation within the Texel breed in lean yield at constant live weight and that this is likely associated with differences between strain and conformation type.

Keywords

carcass compositionconformationmusclesheep
Type
Growth, development and meat science
Information
Animal Science , Volume 72 , Issue 3 , June 2001 , pp. 465 - 475
Copyright
Copyright © British Society of Animal Science 2001

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

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
Butler-Hogg, B. W. and Brown, A. J. 1986. Muscle weight distribution in lambs: a comparison of entire male and female. Animal Production 42: 343–348.Google Scholar
Butterfield, R. M., Zamora, J., James, A. M., Thompson, J. M. and Williams, J. 1983. Changes in body composition relative to weight and maturity in large and small strains of Australian Merino rams. 2. Individual muscles and muscle groups. Animal Production 36: 165–174.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
Cameron, N. D. and Drury, D. J. 1985. Comparison of terminal sire breeds for growth and carcass traits in crossbred lambs. Animal Production 40: 315–322.Google Scholar
Carson, A. F., Moss, B. W., Steen, R. W. J. and Kilpatrick, D. J. 1999. Effects of the percentage of Texel or Rouge de l’ Ouest genes in lambs on carcass characteristics and meat quality. Animal Science 69: 81–92.Google Scholar
Croston, D., Kempster, A. J., Guy, D. R. and Jones, D. W. 1987. Carcass composition of crossbred lambs of ten sire breeds compared at the same carcass subcutaneous fat proportion. Animal Production 44: 99–106.Google Scholar
Cuthbertson, A., Harrington, G. and Smith, R. J. 1972. Tissue separation to assess beef and lamb variation. Proceedings of the British Society of Animal Production (New Series) 1: 113–122.Google Scholar
Ellis, M., Webster, G. M., Merrell, B. G. and Brown, I. 1997. The influence of terminal sire breed on carcass composition and eating quality of crossbred lambs. Animal Science 64: 77–86.Google Scholar
Hopkins, D. L. 1996. The relationship between muscularity, muscle: bone ratio and cut dimensions in male and female lamb carcasses and the measurement of muscularity using image analysis. Meat Science 44: 307–317.CrossRefGoogle ScholarPubMed
Jackson, S. P., Miller, M. F. and Green, R. D. 1997. Phenotypic characterization of Rambouillet sheep expressing the Callipyge gene. II. Carcass characteristics and retail yield. Journal of Animal Science 75: 125–132.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 carcass subcutaneous fat proportion. Animal Production 44: 83–98.Google Scholar
Kempster, A. J., Croston, D. and Jones, D. W. 1981. Value of conformation as an indicator of sheep carcass composition within and between breeds. Animal Production 33: 39–49.Google Scholar
Lawes Agricultural Trust. 1993. Genstat 5 release three reference manual. Clarendon Press, Oxford.Google Scholar
Leroy, P. L. 1989. Growth and carcass performance of purebred Belgian Texel rams tested in station. Proceedings of the 40th annual meeting of the European Association for Animal Production, Dublin, p. 221.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.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: 281–294.Google Scholar
Maniatis, N. and Pollott, G. E. 1998. The dynamics of genetic resources at national level-the British sheep industry as a case study. Proceedings of the sixth world congress on genetics applied to livestock production, Armidale, Australia, vol. 27, pp. 219–222.Google Scholar
Pollott, G. E., Guy, D. R. and Croston, D. 1994. Genetic parameters of lamb carcass characteristics at three end-points: fat level, age and weight. Animal Production 58: 65–75.Google Scholar
Purchas, R. W., Davies, A. S. and Abdullah, A. Y. 1991. An objective measure of muscularity-changes with animal growth and difference between genetic lines of Southdown sheep. Meat Science 30: 81–94.CrossRefGoogle ScholarPubMed
Purchas, R. W. and Wilkin, G. H. 1995. Characteristics of lamb carcasses of contrasting subjective muscularity. Meat Science 41: 357–368.Google Scholar
Simm, G. and Dingwall, W. 1989. Selection indices for lean meat production in sheep. Livestock Production Science 21: 223–233.CrossRefGoogle 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
Thompson, J. M., Butterfield, R. M. and Perry, D. 1985. Food intake, growth and body composition in Australian Merino sheep selected for high and low weaning weight. 2. Chemical and dissectible body composition. Animal Production 40: 71–84.Google Scholar
Thonney, M. L., Taylor, St C. S., Murray, J. I. and McClelland, T. H. 1987. Breed and sex differences in equally mature sheep and goats. 3. Muscle weight distribution. Animal Production 45: 277–290.Google Scholar
Wolf, B. T. 1982. An analysis of the variation in the lean tissue distribution of sheep. Animal Production 34: 257–264.Google Scholar
Wolf, B. T. and Smith, C. 1983. Selection for carcass quality. In Sheep production (ed. Haresign, W.), pp. 493–514, Butterworths, London.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