Hostname: page-component-cd9895bd7-8ctnn Total loading time: 0 Render date: 2024-12-24T02:18:16.189Z Has data issue: false hasContentIssue false
  • English
  • Français

Seasonal changes in tissue weights in Scottish Blackface ewes over multiple production cycles

Published online by Cambridge University Press:  18 August 2016

N. R. Lambe ,
G. Simm ,
M. J. Young ,
J. Conington  and
S. Brotherstone
N. R. Lambe*
Affiliation:
Sustainable Livestock Systems Group, Scottish Agricultural College, West Mains Road, Edinburgh EH9 3JG, UK
G. Simm
Affiliation:
Sustainable Livestock Systems Group, Scottish Agricultural College, West Mains Road, Edinburgh EH9 3JG, UK
M. J. Young
Affiliation:
Sheep Improvement Ltd, PO Box 66, Lincoln University, Canterbury, New Zealand
J. Conington
Affiliation:
Sustainable Livestock Systems Group, Scottish Agricultural College, West Mains Road, Edinburgh EH9 3JG, UK
S. Brotherstone
Affiliation:
Sustainable Livestock Systems Group, Scottish Agricultural College, West Mains Road, Edinburgh EH9 3JG, UK
*
†E-mail: [email protected]
Get access

Abstract

Hill ewes undergo large changes in body fat and muscle weight throughout the annual production cycle as they contend with the pressures of reproduction and lactation, as well as harsh environmental conditions. This study modelled seasonal changes in fat and muscle weights in Scottish Blackface hill ewes throughout their productive lifetime using random regression statistical techniques.

Scottish Blackface ewes (no. = 308) were scanned using computed tomography (CT) four times per year, from 2 until 5 years old. Heritabilities of tissue weights were estimated at 2-weekly intervals throughout the productive life of the ewe. Genetic correlations between tissue weights at the same point in the production cycle at different ages, and between tissue weights at different events within each annual production cycle were predicted. Animal solutions from random regression analyses were used to estimate tissue weights, from pre-mating at 2 years old to weaning at 5 years old. The effects of litter size in the current and previous production years on fat and muscle weights were investigated.

Correlations between CT tissue weights and those predicted by a sin/cos random regression model were 0.87, 0.84, 0.88 for carcass fat, internal fat and muscle respectively. Heritabilities ranged from 0.31 to 0.90 for carcass fat weight, 0.21 to 0.68 for internal fat weight and 0.26 to 0.57 for muscle weight, throughout the productive lifetime of the ewe. Heritabilities were highest during mating for fat weights, and during the dry period and lambing time for muscle weights. Heritabilities of tissue weights in 3-year-old ewes were higher than in other age groups. Genetic correlations were 1.00 between tissue weights at the same scanning event at different ages, but ranged from close to zero to 0.97 between scanning events within age groups. Clearly environmental variation across time was large. The number of lambs produced in both the current and the previous year influenced tissue levels. Ewes that did not produce lambs (barren) in a given year carried more muscle during that year than ewes producing lambs. As ewes aged, barren ewes carried increasingly more carcass fat and muscle than ewes with lambs. Barren ewes also had significantly more muscle during the following year than ewes that had weaned lambs. Ewes that reared twins had significantly less carcass fat the following year than singleton-bearing or barren ewes. These effects of previous litter size increased significantly with age.

Keywords

body compositioncomputed tomographyewes
Type
Research Article
Information
Animal Science , Volume 79 , Issue 3 , December 2004 , pp. 373 - 385
Copyright
Copyright © British Society of Animal Science 2004

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

Anang, A., Mercer, J., Bishop, S. C., Conington, J. and Simm, G. 1995. Effects of divergent selection for leanness on live weight, muscle depth and fat depth of Scottish Blackface ewes. Proceedings of the 46th European Association for Animal Production, Prague.Google Scholar
Armstrong, H. M., Gordon, I. J., Grant, S. A., Hutchings, N. J., Milne, J. A. and Sibbald, A. R. 1997. A model of the grazing of hill vegetation by sheep in the UK. I. The prediction of vegetation biomass. Journal of Applied Ecology 34: 166–185.Google Scholar
Aziz, N. N., Murray, D. M. and Ball, R. O. 1992. The effect of live weight gain and live weight loss on body composition of Merino wethers: dissected muscle, fat and bone. Journal of Animal Science 70: 1819–1828.Google Scholar
Ball, A. J., Thompson, J. M. and Pleasants, A. B. 1996. Seasonal changes in body composition of growing Merino sheep. Livestock Production Science 46: 173–180.Google Scholar
Coffey, M. P., Emmans, G. C. and Brotherstone, S. 2001. Genetic evaluation of dairy bulls for energy balance traits using random regression. Animal Science 73: 29–40.CrossRefGoogle Scholar
Coffey, M. P., Simm, G. and Brotherstone, S. 2002. Energy balance profiles for the first three lactations of dairy cows estimated using random regression. Journal of Dairy Science 85: 2669–2678.Google Scholar
Coltman, D. W., Pilkington, J. G. and Pemberton, J. M. 2003. Fine-scale genetic structure in a free-living ungulate population. Molecular Ecology 12: 733–742.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
Gilmour, A. R., Cullis, B. R., Welham, S. J. and Thompson, R. 2001. ASREML reference manual. NSW Agriculture, Orange, NSW, Australia.Google Scholar
Hammond, J. 1940. Farm animals: their breeding, growth and inheritance. Butler and Tanner Ltd, London.Google Scholar
Horn, P., Kover, G., Repa, I., Berenyi, E. and Kovach, G. 1996. The use of spiral CAT for estimating in vivo body composition. Annual meeting of the European Association for Animal Production, Lillehammer, vol. 47, p. 268.Google Scholar
Jamrozik, J. and Schaeffer, L. R. 1997. Estimates of genetic parameters for a test day model with random regression for yield traits of first lactation Holsteins. Journal of Dairy Science 80: 762–770.Google Scholar
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 In press.CrossRefGoogle Scholar
Jones, H. E., White, I. M. S. and Brotherstone, S. 1999. Genetic evaluation of Holstein Friesian sires for daughter condition-score changes using a random regression model. Animal Science 68: 467–475.Google Scholar
Lambe, N. R., Brotherstone, S., Lewis, R. M., Young, M. J., Conington, J. and Simm, G. 2002. A genetic analysis of seasonal tissue changes in Scottish Blackface ewes, using X-ray computed tomography. Proceedings of the seventh world congress on genetics applied to livestock production, Montpellier, vol. 29, pp. 593–596.Google Scholar
Lambe, N. R., Young, M. J., Brotherstone, S., Kvame, T., Conington, J., Kolstad, K. and Simm, G. 2003a. Body composition changes in Scottish Blackface ewes during one annual production cycle. Animal Science 76: 211–219.Google Scholar
Lambe, N. R., Young, M. J., McLean, K. A., Conington, J. and Simm, G. 2003b. Prediction of total body tissue weights in Scottish Blackface ewes using CT scanning. Animal Science 76: 191–197.Google Scholar
Lewis, R. M. and Brotherstone, S. 2002. A genetic evaluation of growth in sheep using random regression techniques. Animal Science 74: 63–70.Google Scholar
Meyer, K. 2002. Estimates of covariance functions for growth of Australian beef cattle from a large set of field data. Proceedings of the world congress on genetics applied to livestock production, Montpellier, communication no. 11-01 (cd-rom).Google Scholar
Riney, T. 1955. Evaluating condition of free-ranging red deer (Cervus elaphus), with special reference to New Zealand. New Zealand journal of Science and Technology 36: 429–463.Google Scholar
Schaeffer, L. R. and Dekkers, J. C. M. 1994. Random regression in animal models for test-day production in dairy cattle. Proceedings of the fifth world congress on genetics applied to livestock production, Guelph, vol. 18, pp. 443–447.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
Thompson, J. M. and Ball, A. J. 1997. Genetics of meat quality. In The genetics of sheep (ed. Piper, L. and Ruvinsky, A.), pp. 523–538. CAB International, Wallingford.Google Scholar
Weber, M. L. and Thompson, J. M. 1998. Seasonal patterns in food intake, live mass, and body composition of mature female fallow deer (Dama dama). Canadian journal of Zoology 76: 1141–1152.Google Scholar