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Variance components due to direct and maternal effects and estimation of breeding values for 12-week weight of Welsh Mountain lambs

Published online by Cambridge University Press:  18 August 2016

M. Saatci ,
I. Ap Dewi  and
Z. Ulutas
M. Saatci
Affiliation:
School of Agricultural and Forest Sciences, University of Wales, Bangor LL57 2UW
I. Ap Dewi
Affiliation:
School of Agricultural and Forest Sciences, University of Wales, Bangor LL57 2UW
Z. Ulutas
Affiliation:
School of Agricultural and Forest Sciences, University of Wales, Bangor LL57 2UW
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Abstract

The purpose of this study was to examine the importance of the genetic and maternal environmental factors influencing the 12-week weight (12WW) of Welsh Mountain lambs and to estimate genetic parameters for this trait. Records of 8880 Welsh Mountain lambs born between 1979 and 1995 were analysed. The records were from the nucleus flock of the CAMDA cooperative breeding group. In this flock selection of replacements had been based on a multi-trait index incorporating lamb growth and maternal ability as important objectives and 12WW as one of the selection criteria. Twelve models were examined, all including direct additive genetic variance and various combinations of genetic and environmental maternal effects. The most appropriate model was chosen based on log-likelihood ratio tests. It included appropriate fixed effects, and direct additive, maternal additive, maternal permanent environment and maternal common environment (litter) random effects that defined proportionally 0⋅21 (h2), 0⋅09 (m2), 0⋅06 (pe2) and 0⋅18 (ce2) of the phenotypic variance. Ignoring the additive maternal effect resulted in inflated estimates of direct heritability and ignoring the environmental effects associated with dam inflated the direct and maternal heritabilities. There was no correlation (P < 0⋅05) between the additive direct and additive maternal effects. Additive direct and maternal breeding values increased by 0⋅12 (s.e. 0⋅006) kg/year and 0Ό3 (s.e. 0⋅003) kg/year respectively. The results demonstrate the effective incorporation of selection index methodology in the context of a hill sheep flock and also the importance of several categories of maternal effects.

Keywords

body weightbreeding valuesgenetic parametersmaternal effectssheepweaning weight
Type
Research Article
Information
Animal Science , Volume 69 , Issue 2 , October 1999 , pp. 345 - 352
Copyright
Copyright © British Society of Animal Science 1999

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References

Atkins, K.D. 1984. Genetic parameters of body weights in hill sheep. Animal Production 38: 531 (abstr.).Google Scholar
Bradford, G.E. 1972. The role of maternal effects in animal breeding. VII. Maternal effects in sheep. Journal of Animal Science 35: 1324–1334.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
Croston, D. and Pollott, G. 1994. Planned sheep production, second edition. Collins, London.Google Scholar
Crump, R.E., Haley, C.S., Thompson, R. and Mercer, J. 1997. Individual animal model estimates of genetic parameters for performance test traits of male and female Landrace pigs tested in a commercial nucleus herd. Animal Science 65: 275–283.Google Scholar
Diop, M. and Van Vleck, L.D. 1998. Estimates of genetic parameters for growth traits of Gobra cattle. Animal Science 66: 349–355.Google Scholar
Fahmy, M.H. 1996. Growth, fertility, prolificacy and fleece weight of Romanov, Finnsheep and Booroola purebreds and their first cross and backcross with the DLS breed. Animal Science 62: 479–487.Google Scholar
Falconer, D.S. and Mackey, T.F.C. 1996. Introduction to quantitative genetics, fourth edition. Longman, Harlow, Essex.Google Scholar
Fogarty, N.M. 1995. Genetic parameters for live weight, fat and muscle measurements, wool production and reproduction in sheep: a review. Animal Breeding Abstracts 63: 101–143.Google Scholar
Gerstmayr, S. 1992. Impact of the data structure on the reliability of the estimated genetic parameters in an animal model with maternal effects, Journal of Animal Breeding and Genetics 109: 321–336.Google Scholar
Gilmour, A.R., Cullis, B.R., Welham, S.J. and Thompson, R. 1998. ASREML. NSW Agriculture, Orange, Australia.Google Scholar
Hagger, C. 1998. Litter, permanent environmental, ram-flock, and genetic effects on early weight gain of lambs. Journal of Animal Science 76: 452–457.Google Scholar
Khombe, C.T., Hayes, J.F., Cue, R.I. and Wade, K.M. 1995. Estimation of direct additive and maternal additive genetic effects for weaning weight in Mashona cattle of Zimbabwe using an individual animal model. Animal Science 60: 41–48.CrossRefGoogle Scholar
Koch, R.M. 1972. The role of maternal effects in animal breeding. VI. Maternal effects in beef cattle. Journal of Animal Science 35: 1316–1323.Google Scholar
Maria, K.G., Boldman, K.G. and Van Vleck, L.D. 1993. Estimates of variances due to direct and maternal effects for growth traits of Romanov sheep. Journal of Animal Science 71: 845–849.Google Scholar
Meat and Livestock Commission. 1986. Sheep yearbook 1986. Meat and Livestock Commission, UK.Google Scholar
Meat and Livestock Commission. 1988. Sheep in Britain. Meat and Livestock Commission, UK.Google Scholar
Meat and Livestock Commission. 1989. Sheep yearbook 1989. Meat and Livestock Commission, UK.Google Scholar
Meat and Livestock Commission. 1992. Sheep yearbook 1992. Meat and Livestock Commission, UK.Google Scholar
Meat and Livestock Commission. 1993. Sheep yearbook 1993. Meat and Livestock Commission, UK.Google Scholar
Meat and Livestock Commission. 1998. Sheep yearbook 1998. Meat and Livestock Commission, UK.Google Scholar
Meyer, K. 1992. Variance components due to direct and maternal effects for growth traits of Australian beef cattle. Livestock Production Science 31: 179–204.CrossRefGoogle Scholar
Mrode, R.A. 1996. Linear models for the prediction of breeding values. CAB International, Wallingford.Google Scholar
Notter, D.R. and Hough, J.D. 1997. Genetic parameter estimates for growth and fleece characteristics in Targhee sheep. Journal of Animal Science 75: 1729–1737.Google Scholar
Pollott, G.E., Croston, D. and Guy, D.R. 1994. Genetic progress in the CAMDA group breeding scheme nucleus. Animal Production 58: 431 (abstr.).Google Scholar
Purser, A.F. and Young, G.B. 1983. Mothering ability in two hill flocks. British Veterinary Journal 139: 296–306.Google Scholar
Rodriguez-Almedia, F.A., Van Vleck, L.D. and Gregory, K.E. 1997. Estimation of direct and maternal breed effects for prediction of expected progeny differences for birth and weaning weights in three multibreed populations. Journal of Animal Science 75: 1203–1212.Google Scholar
Saatci, M. 1998. Genetic parameters of production traits in Welsh Mountain sheep. Ph.D. thesis, University of Wales, Bangor, UK.Google Scholar
Simm, G. 1998. Genetic improvement of cattle and sheep. Farming Press, Ipswich.Google Scholar
Tosh, J.J. and Kemp, R.A. 1994. Estimation of variance components for lamb weight in three sheep populations. Journal of Animal Science 72: 1184–1190.Google Scholar
Vaez-Torshizi, R., Nicolas, F.W. and Raadsma, H.W. 1996. REML estimates of variance and covariance components for production traits in Australian Merino sheep, using an animal model. 1. Body weight from birth to 22 months. Australian Journal of Agricultural Research 47: 1235–1249.Google Scholar
Van Wyk, J.B., Erasmus, G.J. and Konstantinov, K.V. 1993. Variance components and heritability estimates of early growth traits in the Elsenburg Dormer stud. South African Journal of Animal Science 23: 72–76.Google Scholar
Wang, L.X., Zhang, Y. and Pan, J.Q. 1993. Estimation of variance components and genetic parameters of maternally influenced growth traits in sheep. Acta Veterinaria et Zootechnica Sinica 24: 289–293.Google Scholar
Willham, R.L. 1972. The role of maternal effects in animal breeding. III. Biometrical aspects of maternal effects in animals. Journal of Animal Science 35: 1288–1293.Google Scholar